DIY – How to Safety Wire a Drain Plug
06-14-2012, 08:06 PM
#1
Burning Brakes
Thread Starter
DIY – How to Safety Wire a Drain Plug
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
There are two basic reasons to safety wire a drain plug.
Ř Absolutely prevent the drain plug from falling out. An engine, transmission, differential, etc. just cannot run without oil. And if you accidentally forget to completely tighten the drain plug, the safety wire will still prevent the plug from falling out, even if it may be leaking.
Ř Significantly reduce the wear on aluminum drain-plug threads in any oil pan or oil-sump, by reducing the torque on the drain plug. Safety wire prevents the drain-plug from falling out, even with the reduced torque. Every time a drain plug is removed and replaced, there is a little wear on the aluminum threads in the hole. And it only takes once to over-torque a plug, and strip the threads in the drain hole.
WARNING: do not reduce the torque on any fastener other than the drain plug, ever, never. The manufacturer specified torque on fasteners is what holds things together. Reducing the torque can lead to parts breakage, or a serious accident. But a drain plug is not holding anything together, it is just plugging a drain hole.
Safety wiring a fastener/ drain plug is pretty straight forward. Amateur racers do it all of the time, as it is required, to prevent oiling the track if the drain plug should fall out. Even on a street only driven vehicle, safety wiring can be a good idea.
However, the main problem for first-timers, is finding an appropriate anchor place/ hole to attach the wire from the bolt/ plug. That is the reason for this post, since a proper anchor point will differ for each vehicle and specific fastener.
The FOLLOWING TOPICS are COVERED IN THIS POST
CONSEQUENCES of OIL PAN THREAD DAMAGE:
THE PICTURES SHOWING HOW TO SAFETY WIRE A BOLT:
RULES FOR SAFETY WIRING:
WHAT CAUSES DAMAGE TO DRAIN PLUG-HOLE THREADS?
HOW DIFFICULT IS IT TO SAFETY WIRE A DRAIN PLUG?
WHAT CAN GO WRONG WHEN SAFETY WIRING?
DRILLING THE ANCHOR HOLE:
DRILL BITS AND SAFETY WIRE SIZES:
DRILLING THE DRAIN PLUG:
WIRING THE DRAIN PLUG:
IS IT SAFE TO REDUCE THE OEM TORQUE ON A DRAIN BOLT?
SO WHAT TORQUE SHOULD BE USED ON A DRAIN PLUG
HOW TO GET A CONSISTENT TORQUE READING ON A DRAIN BOLT:
CAN A SEALING WASHER BE REUSED ON A DRAIN BOLT?
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
RDX OEM DRAIN BOLT SIZES:
RDX ALTERNATE DRAIN BOLT CONSIDERATIONS:
Ř THREAD LENGTH CONSIDERATIONS
Ř AN ACCURATE THREAD COUNT
Ř TORQUE CONSIDERATIONS for NON-OEM DRAIN BOLTS
================================================== ==
CONSEQUENCES of OIL PAN THREAD DAMAGE:
Replacing an RDX engine oil pan, because of damaged drain hole threads, can easily cost $1,000 because of the labor involved. The oil pan cannot be dropped without removing/ lowering the RDX front frame cradle (to which the front suspension is attached).
And replacing an RDX case for a transmission, transfer-drive, or differential can cost more than is practical on a 5 year old car. Case replacement requires unit disassembly.
Thread hole repair with a Heli-Coil® is possible, but may not be practical, depending upon the amount of material around the hole. A Heli-Coil® repair is something to consider, if you have a problem with a stripped drain plug hole. A Heli-Coil® repair is a procedure to drill out the damaged hole-threads, and then to insert a coil of steel (new threads) into the original hole. After the original hole has been drilled and re-tapped for the Heli-Coil®, pour 4 quarts of cheap engine oil through the engine, with the drain plug removed. That will (probably) flush-out any aluminum chips in the engine oil-sump, from repairing the drain hole. By the way, Heli-Coil® is only one brand of thread-repair, but has basically become a generic term.
If you doubt that Honda/ Acura engine oil-pans ever have the drain hole threads stripped, there are Honda TSBs out detailing how to do a Heli-Coil® repair on aluminum hole-threads. And there are aftermarket sellers of various repair-procedures for steel Honda engine oil pans.
================================================== ==
THE PICTURES SHOWING HOW TO SAFETY WIRE A BOLT:
************************************************** ******
RULES FOR SAFETY WIRING:
Here is a link to a nice PDF publication on fasteners in general, with a special section (7) on safety wiring. Sorry if this violates any forum rules about posting links.
http://www.airweb.faa.gov/Regulatory...apter%2007.pdf
Here, I have expanded the basic safety wiring rules from the PDF file from the link just above. There are not really that many rules to remember. I have sort of restated the basic rules in different ways, to emphasize that a few basic ideas are really, really, important.
Ř The edges of all safety wire holes should be chamfered or beveled, both the holes in the fastener and the anchor hole. That prevents the edge of the hole from cutting the wire. If the wire is wrapped around a part as an anchor point, the wire should not bear on any sharp edge.
Ř When twisting the wire, hold the two ends at 90 degrees to each other, and at 45 degrees to the run of twisted wire. Use 6 to 8 twists per inch.
Ř Never wire a fastener that is on one part, to an anchor hole on a separate part, unless the two parts are solidly bolted together. There should be no motion between the two parts. Otherwise, the relative motion between the two separate parts will break the safety wire.
Ř Safety wire must be installed so that it tends to pull the fastener tighter, so that the fastener cannot loosen
Ř Install safety wire where practical with the wire wrapped around the head of the bolt, screw, or nut, and positioned so that the loop of the wire fits closely to the contour of the fastener being safety wired. The wire must be twisted so that the loop is held in place, and does not flip up. If there is a clearance problem, the wire may be wrapped over the fastener rather than around it.
Ř Safety wire must not be overstressed. It will break under vibrations if twisted too tight, just tighten it by hand. Do not use pliers to tighten the twists you have made by hand. If your hand twists are too loose, do it over.
Ř Safety wire must be pulled taut when being twisted, and maintain a light tension when secured. If left loose it will break from vibration. You can use pliers to pull it taut after routing through the anchor hole. But only pull on the wire beyond where it will be twisted at the anchor hole. And if it is not taut when complete, you must cut out your work and do it over.
Ř Bend the ends under and inward, when complete, so that you do not poke you eye out, or rip your hand next time you are under the car.
Ř Do not mutilate the twisted section of wire. Use pliers to pull only on the ends, beyond where the wire will be terminated at the anchor hole. Safety wire must not be nicked, kinked, or mutilated. This will cause a weak spot. Mr. Murphy will then cause the wire to break, allowing the drain plug to fall out.
Ř Leave at least 4 to 6 complete twisted turns, after the loop through the anchor hole. That is the pig-tail. You can use pliers in one hand, to help pull the wire taut, and to make the twists at the anchor hole. Cut, do not twist off the excess wire at the end. Use LineMan pliers to make the cut. Regular diagonal pliers will be ruined cutting a double twist of wire. They are OK to cut a single strand of wire.
Ř When removing the safety wire, cut rather than twist the wire to remove it. Cut at both the bolt, and at the anchor hole. Then use pliers to pull it free (you are wearing your safety goggles, right?)
Ř When twisting the wire between the plug head and the anchor hole, if you miscalculate the length, DO NOT untwist the wire to make it fit the space to the anchor hole. You MUST cut out the wire you are working with, and begin again with a new length of wire. Failure to follow this rule will again cause the wire to break, and the plug to fall out. Wire is cheap, your engine is not.
================================================== ====
WHAT CAUSES DAMAGE TO DRAIN PLUG-HOLE THREADS?
If the threads on both the plug and hole are not clean, wear can occur when the drain plug is inserted and torqued. Clean the drain-plug threads every time the plug is removed. Either actually wash and dry the drain bolt, or use brake/ electrical spray cleaner. The drain-hole threads should be clean from the oil draining out, but check anyway.
Each time that a drain plug is torqued into the drain hole, the drain hole threads are stressed. Just as a point of reference, the MID (multifunction indicator display) on my RDX hits 15% every 3800-4000 miles, just like clockwork. In 250K miles that would be over 60 oil changes. But I actually change oil every 2K miles, so that would be a total of over 120 oil changes. Threads eventually wear and fail. How soon they fail depends upon the stress level, or the amount of toque used on the drain plug.
Actually, the real problem is that it only takes once to strip aluminum drain-hole threads. One time at a quickie lube place, the 300 pound ‘mechanic’ tightened the engine oil drain plug in my Chevy 4x4 to over 100 ft-lbs, instead of the specified 18 ft-lbs. Torque that high would have stripped the aluminum drain-hole threads in an RDX.
But the Chevy aluminum oil pan threads were not damaged, because the drain-hole is Heli-Coiled®. That means that stainless-steel threads were OEM inserted into the aluminum pan drain-hole, by GM. So steel drain-plug threads bear against steel drain-hole threads in the oil pan. However, I will note that in this case, the Chevy steel drain-plug head-flange, actually damaged the flat part of the oil pan around the hole. So, exert enough force and anything can be ‘broken’.
Typically, a Heli-Coil® is strong enough that the inserted and torqued bolt will break, before the Heli-Coil® threads in the insertion hole will be damaged, even in an aluminum hole. Too bad Acura did not use Heli-Coils® in the RDX drain-pans.
HOW DIFFICULT IS IT TO SAFETY WIRE A DRAIN PLUG?
The short answer is: “NOT VERY DIFFICULT”. After all, every amateur racing organization, from go-carts to motorcycles to every kind of car racing, requires that the drain plugs be safety wired (as well as a number of other safety related fasteners). If the average 20 year-old can do it, so can you. I suggest that you read a few articles on the internet. You can also simply pay your local machinist to drill the drain plug(s) for you.
Most amateur race groups have posted online articles describing safety-wiring, usually for specific vehicles. That is the reason for this post. Safety-wiring in general is pretty simple. Where people seem to have problems, is finding a proper anchor point, for a particular fastener on a particular vehicle.
WHAT CAN GO WRONG WHEN SAFETY WIRING?
Buy a spare drain plug, and no matter what happens, you still have the original plug. But if you simply drain the oil, then start drilling the drain-plug, well, if you really mess-up the plug, then you are sort of ‘stuck’ aren’t you? Still, likely the only thing wrong with the drain plug is it has a damaged safety-wire hole in it. It still works just fine as a drain plug.
Where you can do serious damage, is when you drill the anchor holes for the plug-wire. There has to be a place to anchor the wire from the drain-plug. Typically, there will not be an already existing place on the engine to anchor the safety-wire from a drain plug.
IF YOU DRILL A HOLE INTO THE PAN OR CASE THAT CAUSES A LEAK, DO NOT BLAME ME. DRILL ONLY THROUGH A CASE STRENGTHENING RIB, NOT INTO THE CASE ITSELF.
DRILLING THE ANCHOR HOLE:
The anchor hole basically has to be drilled into a case structural rib, next to where the drain-plug is installed. For the engine, that means the oil-pan. For the transmission, that means the transmission case (there is no pan). Etc. If possible, it is best to place the anchor hole nearer the edge than the case body.
Look at this picture of the BLAZER ENGINE oil drain plug. Look at both anchor holes. If the rib is too narrow, find another place for the anchor hole.
For example, it might seem like a good anchor hole could be drilled into the lower engine skid plate. But that plate is bolted to the body frame, not the engine. And the engine is mounted on rubber mounts, allowing the engine to move relative to the frame. So the skid plate cannot be used for an anchor hole for the engine drain plug. Besides, you would not want to unwire the drain plug every time you removed the skid plate. So give some thought to just where you will anchor any drain plug.
Do not under any circumstances drill the anchor hole in a part that can move relative to the part with the drain plug hole. Drill the anchor hole at least 1/8 inch, and preferably about 1/4 inch from the edge of the web. Too close to the edge of a structural web, and the hole can crack out to the edge.
Also chamfer (bevel the edge of) the anchor hole slightly. That just means use a 3/16 inch or 1/4 inch drill bit, and counter-sink the 1/16 inch anchor hole. Just a little is necessary, to knock off the sharp edge of the 1/16 inch hole. That will prevent a crack (around the hole) from starting in that aluminum casting that is your oil pan. It will also keep the edge of the anchor hole from cutting and breaking the safety wire. For the same reason, the hole(s) in the bolt head must also be chamfered.
I use a 3/16 inch drill bit to chamfer safety-wire holes, both those in the bolts, and any anchor hole. I turn the drill bit by hand. Yes, by hand, not in a power drill. With a power drill, it is just too easy to mess up an anchor hole in an aluminum rib. Even turning the drill by hand, you can drill too far into aluminum with the larger bit. Remember, you are not drilling a hole, just slightly chamfering the edges of the existing anchor hole. Turning the chamfer bit by hand, will also give you greater access in cramped areas, than will a power drill.
DRILL BITS AND SAFETY WIRE SIZES:
Drill the plug and anchor holes with a 1/16 inch bit. When space is limited, the anchor hole may be drilled with a 3/64 inch bit, but no smaller. Use 0.032 inch diameter 304-type soft (annealed) stainless steel wire. Twist the safety-wire by hand, as I have been doing for 40 years or so. I find that the special twist tool pliers just get in my way.
Use only titanium 1/16 drill bits. An ordinary HS (high-speed) black oxide drill bit will work, but will drill only one bolt-hole, before becoming hopelessly dull. A titanium bit will drill 3-4 holes, so it is actually cheaper if drilling more than one plug. And buy two bits at least, you will probably break the first one. Do not use carbide bits. They are supposedly sharper, but they are also brittle, and you will need to push the drill bit with considerable force against the drain-plug head.
Also, buy a one pound spool of wire. Yes, you can purchase 25-feet of racers-wire from any motorcycle shop. But it takes 2-feet of wire to wire a plug. That is always the case, no matter how short the actual run of wire from the plug to the anchor hole. You need enough extra wire to hold it by hand, and pull it tight. Then clip off the extra wire. It was not wasted, you simply cannot properly wire a plug with less than 2 feet of wire. And beginners will likely need 3 feet, the first time-or-two.
Safety wire can be purchased online or mail-order from Pegasus Racing, or another similar race-shop. I purchased a one pound roll of 0.033 inch 304 wire, from a local tool supplier. One pound of wire is about 300+ feet.
DRILLING THE DRAIN PLUG:
Use masking tape on all of the plug except for the head, especially if the plug has a magnet. This will keep particles off the magnet, and also protect the threads if the drill-bit should slip.
Heat is what dulls the drill bits. A light 10-weight machine oil in the hole (while drilling), will help to cool the bit. And you can only drill about 1/16 inch deep or so, before the drill bit (and bolt) will become hot. Pull back the drill bit, oil the hole, and wait to cool. Or even take the bolt and run cold water over it. Yes, the bolt can get so hot you cannot hold it, while drilling. That will permanently dull the drill bit. Unless you take care, the small 1/16 inch drill bit can be dulled while drilling only 1/8 inch into the bolt. But if you keep the bit cool, a titanium bit can drill 4 holes completely though a bolt head.
If you tighten the plug to exactly the same torque each time, and use the same type of washer (same thickness) each time, the plug head will position within 15 degrees (or less) of rotation, every time. That means that the plug safety wire hole will align in exactly the same spot every time.
If you mark the drain plug with finger-nail polish, while it is properly torqued, you will know exactly which head-flat to drill. If you use different thickness washers, then you may need to drill three rather than one hole in a hex head bolt.
For the RDX transmission and differential drain plugs, you can just drill two through-holes, as there are only four flats (internal). Actually, the easy way is to drill four holes, to make the two through holes. The two holes on opposite sides of the bolt head do not have to align perfectly – they do not on my own drain bolts.
You do not need to drill a 90 degree perfectly aligned hole through the plug head. I do not own a drill press, which would make drilling the bolt much easier. I have a Sears drill-press stand, which holds a hand drill, sort of like a drill press. And I never figured a way to hold the bolt with a vise, as the drain plug head has that shoulder (molded washer ring) on it. So I had to hold the bolt by hand (use gloves), pressed into a piece of heavy Styrofoam on the drill stand base. Just center punch the place you are going to drill, 5 or 6 times to make a really good starting place for the drill bit. Use your goggles while drilling please.
Safety wire drilling jigs are available for hex bolt heads. But they will not work with RDX drain plugs, because of the round washer-sealing flange/ shoulder on the hex head. And the jigs will not work on a round head bolt.
Safety wire holes in a drain plug head must be chamfered/ beveled, so that the sharp edge (of the hole) does not break the safety wire. Just use a larger drill bit to do this.
When drilling, use a 10 weight oil, or machine/ sewing machine oil for lubrication. Remove the drill bit frequently from the hole to remove drilled chips from the hole. If you press too hard, the drill bit will flex, then break. The bit will get really hot, unless you stop every so often. That is the reason for using a titanium bit, it can handle the heat better than any other type of bit.
WIRING THE DRAIN PLUG:
Wear completely side-covering safety goggles, the Lexan kind that are shatter proof. If you do not, sure as hell you will stick the sharp end of the wire into your eye, while twisting the wire, thereby blinding yourself. I do get the occasional scratch on my face, or a hand or wrist. So keep your Tetanus shot up-to-date. I sometimes use the form fitting nitrile gloves, Any other glove will not protect your hands because it rips, or will fit so loosely that you cannot twist the wire. Generally, I do not wear gloves because they do not allow enough control for me. But I do wear a long sleeve shirt, because otherwise, I get many wire scratches on my wrists.
When twisting and routing the safety wire, you MUST NOT touch the wire anywhere between the bolt head and the anchor hole, with anything metal (meaning a set of pliers). Doing so will nick the wire, creating a weak point, which taking into account SOD’s Law, will cause the wire to break, the plug to fall out, your engine to run out of oil, and ensure destruction of the engine before you notice the problem.
Yes, that means you must cut a virgin 2-foot length of wire, and completely safety wire the plug using only your hands, and only pull the wire tight with pliers by pulling only on the very end of the wire, BEYOND THE PIGTAIL, WHERE THE WIRE IS TERMINATED AT THE ANCHOR HOLE.
That is why I find the safety wire pliers useless. Most people do not understand the proper use of these pliers, and inevitably damage the safety wire-run between the plug and anchor hole.
IS IT SAFE TO REDUCE THE OEM TORQUE ON A DRAIN BOLT?
Yes. A drain bolt is just a sealing-plug. It is not holding two parts together. The only concern with a reduced torque, is will there be a leak, and will the bolt fall out? Neither is a concern if safety wire is used.
Never reduce the specified OEM torque on a structural bolt (holding two parts together).
Normally, a bolt is used to clamp two parts together. The clamping force of the bolt, when torqued to specification, is what holds everything together, and also prevents the bolt from loosening. A properly torqued bolt has stretched slightly, and bolt-elastically holds the two parts together, and prevents the bolt from loosening.
SO WHAT TORQUE SHOULD BE USED ON A DRAIN PLUG?
Any reasonable torque on a drain bolt is OK, so long as (1) the washer does not leak, and (2) the bolt does not fall out. 18 or 19 ft-lbs is plenty of torque to seal the washer, especially a copper washer. Actually, I have never had an aluminum washer leak either, when using that torque. And safety wiring the bolt will ensure that the plug does not fall out.
The OEM drain plugs torque on my Chevy 4x4 are specified as either 18 ft-lbs (engine plug with rubber O-ring washer), or 19 ft-lbs (front differential plug with nylon washer).
The actual torque that I use on all RDX drain bolts, is 225 in-lbs, which is 18.75 ft-lbs. I use 225 in-lbs because that is a specific clear marking on my torque wrench.
The only exception is the transmission fill plug. I have reduced the OEM torque from 33 ft-lbs to 25 ft-lbs. The bolt sealing washer is lubricated with transmission fluid before torque. I use 25 ft-lbs instead of 19 ft-lbs, because the transmission fill bolt cannot be safety wired. I use an aluminum washer, and because it galls slightly, that bolt has never loosened. It gives a nice ‘pop’ each time I remove it. I have reused that particular washer about 10 times.
HOW TO GET A CONSISTENT TORQUE READING ON A DRAIN BOLT:
Despite what any mechanic may tell you, a torque wrench is required to get a valid bolt torque. There is simply no way to get an accurate torque setting ‘by-feel’, I do not care how long you have been a mechanic, not at low torque settings (and probably not at high torque settings either).
To prevent galling and to get a very consistent torque, I oil both sides of the sealing-washer. It does not matter what kind of washer I use, I oil it. The oil prevents the washer from galling (sticking), while I am trying to torque the drain plug. Be aware that a bolt with an oiled washer will have the same torque as a bolt with a dry washer, at a reading that is 20% lower. That is, the oiled bolt will read 80 ft-lbs when the dry bolt will read 100 ft-lbs, with exactly the same amount of force on the torque wrench. Except that you will be lucky to get a consistent and valid torque with the dry bolt and washer.
Also, check that both the bolt shoulder and washer are clean, especially if you are reusing the washer. Simply press the oiled washer against the bolt sealing surface. Then twist (rotate) the washer back and forth with your fingers, feeling for any grittiness. It should feel perfectly smooth. Check both sides of the washer against the bolt shoulder, before installation. And wipe clean the case sealing surface, around the hole.
Under even low torque (pressure), a dry aluminum washer will gall. The word gall means “to cold-weld”, and that is exactly what the washer does – it spot welds itself to the aluminum pan (and the drain bolt head). That is why a drain plug installed with a dry washer typically requires much more effort to remove, than it did to tighten. Galling is much less of a problem with a copper or nylon washer.
Do not use a 100 ft-lb torque wrench to torque drain bolts on your RDX, and definitely not a 150 ft-lb wrench. You should be aware that a torque wrench is not accurate at the lower 20% and the upper 20% of the torque range. That means that a torque wrench with a maximum range of 50 ft-lbs, is not accurate below 10 ft-lbs or above 40 ft-lbs. That means that a 100 ft-lbs torque wrench is not accurate below 20 ft-lbs or above 80 ft-lbs. This is why I also have a torque wrench for very low torque that reads only to 12 ft-lbs (150 in-lbs).
An inexpensive beam-type torque-wrench is only around $20-30 and some are 2% accurate which is about as close as you will be able to read the wrench markings anyway. By the way, that is 2% of the total reading of the wrench. For a 150 ft-lb wrench that means even the lowest reading is accurate only to +/- 3 ft-lbs = 2% of 150.
CAN A SEALING WASHER BE REUSED ON A DRAIN BOLT?
I reuse copper and nylon washers once-or-twice. With the low torque I am using, an aluminum washer can sometimes also be reused once.
Hand tighten the bolt, until the washer is snug against the case. Then tighten the bolt with a torque wrench. Judge whether a washer can be reused, by how many degrees of bolt rotation are required to get a valid torque. If the washer has been crushed after multiple uses, only a few degrees of rotation of the bolt will be required to get the torque you are using. It is very difficult to get a consistent/ valid torque, if the bolt only moves 10 or 15 degrees of rotation, from zero to full torque. In that case, use a new washer.
A new washer, whether aluminum or copper, generally requires less than 45 degrees or 1/8 turn of bolt rotation, for a proper 19 ft-lb torque. That is an approximation. Many factors are involved, so use a torque wrench.
RDX drain bolts are large bolts (with a large washer). Honda specifies a high drain-bolt torque because of the large solid aluminum washer. Aluminum requires a lot of force to crush, if not to seal. An aluminum washer is much harder than a copper or nylon washer. The crush is to prevent the plug from loosening, not to seal.
Trying to reuse an aluminum washer, once it has been crushed, it will be difficult to get a consistent torque. That is why a new aluminum washer is supposed to be used for each oil change. However, if a lower than OEM torque is used, an aluminum washer may possibly be re-used once or twice.
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
Then there is no need to drill it yourself for safety wire. Any Honda (after the late ‘80s) or Acura uses the same engine oil drain plug: 14mm diameter x 1.5mm thread pitch. There are many online sites selling an engine oil drain plug, that is already drilled for safety wiring.
Plugs are available in aluminum, steel, and titanium. If the plug has a magnet, buy only a steel plug. Otherwise, only the glue is holding that magnet in place, and glue has been know to fail. That would allow the magnet to stick to some undesirable internal moving part and cause damage. Steel plugs with a magnet are OK, because the magnet is going to continue sticking to the drain plug if the glue fails.
But you can also purchase an aluminum drain plug without a magnet, although I have not seen any that are already drilled. The only drilled aluminum drain plugs that I have seen have magnets. Aluminum is MUCH easier to drill for safety wiring, than steel.
The problem with a pre-drilled plug is that the safety wire hole may not be in the position that is needed, when the plug is properly torqued. Look at the pictures in this post, and note that some of the drain plugs have two holes. Note that for the engine drain plugs, only one hole position is appropriate. Also, if you switch between washers of different thicknesses (aluminum/ copper), the drilled safety wire hole will position differently for the same bolt torque.
RDX OEM DRAIN BOLT SIZES:
The length given in the table below, is the length under the bolt head to the end of the bolt. It is NOT the thread length. What is the significance of the number of threads on each plug? See the next section. The thread count below considers only fully formed threads. And disregards whether or not the bolt thread can actually engage the internal threads inside the drain hole. Again, see the following sections for further explanation.
ENGINE OIL PAN:.............. 14mm x 1.5 x 15mm length – 7.5 threads
TRANSFER CASE DRAIN AND FILL: 20mm x 1.5 x 14mm length - 6.5 threads
REAR DIFFERENTIAL FILL:...... 20mm x 1.5 x 16mm length – 7.5 threads
REAR DIFFERENTIAL DRAIN:..... 18mm x 1.5 – 5.5 threads
TRANSMISSION DRAIN:.......... 18mm x 1.5 – 5.5 threads
The transmission drain plug, and the rear differential drain plug, are the same part number (same plug). The end (tip) of these plugs has no threads, with the magnet (inserted into) the end of these plugs. The magnet is crimped or swaged in place, no sign of glue. The magnet is 15.5mm Length x 6mm Diameter.
RDX ALTERNATE DRAIN BOLT CONSIDERATIONS:
If using a non-OEM drain plug, consider the length of the new plug. This will be important if replacing an OEM plug with a magnetic one, or with a different head style. If the alternate bolt length is longer, is there room inside the case, without hitting some interior part? Is there room for a magnet on the end of the new plug, to project into the case, without hitting something?
Is the alternate drain plug shorter than the OEM plug? Are there enough threads on the shorter plug to achieve an acceptable torque value, without stripping the threads in the drain hole?
THREAD LENGTH CONSIDERATIONS:
How can a bolt have 1/2-thread? Look at the bolt from the side, then count the threads along-side each edge. Count only threads which are fully formed, and of full height. If the count differs by one, from one side of the bolt to the other, then one full-height thread only circles one-half of the bolt. That makes half-a-thread. The half thread will be either just under the bolt head, or at the end/ tip, or both.
AN ACCURATE THREAD COUNT:
Place the proper washer onto the drain bolt. Any thread which is closer to the washer, than the distance between two threads, should not be counted. That is because the bolt drain hole is counter-sunk/ chamfered. That is, the threads inside the bolt hole do not extend completely to the edge of the hole opening. Therefore, there is no inner hole-thread to engage with the bolt-thread nearest the bolt head. Sometimes, the bolt thread just under the head, can be forced to engage a thread inside the hole, by using a thinner washer. Copper washers are generally half the thickness of aluminum washers.
Consider both the Transmission and Rear Differential drain plugs (same plug/ same Acura part number). The drain plug has 5.5 threads, but with an OEM aluminum sealing washer installed, only 5 full-threads can engage with the threads inside the drain hole.
Any bolt thread which is not the same “full-height” as all other threads, will not fully engage the threads inside the drain hole. Examine the threads on a drain bolt carefully. Is the thread just under the bolt head, or at the end of the bolt, fully formed? Is it the same height as the other threads, with a sharp edge, or lower with a rounded edge? Is this thread fully separate, or partly machined into the area near the bolt end/ tip? Any condition which prevents a bolt thread from fully engaging with the drain hole threads, means that this bolt thread is not supporting the full force of the bolt torque, or even no force at all.
Finally, look at the threads inside the bolt drain hole. If the bolt has 7 threads, but there are only 6 threads inside the bolt hole, then only a maximum of 6 bolt threads can engage. This should be taken into account when replacing an OEM bolt, in determining a proper bolt length.
TORQUE CONSIDERATIONS for ALTERNATE DRAIN BOLTS:
If an OEM bolt has 7 threads, and has a torque specification of 35 ft-lbs, then each bolt thread is exerting a force of 5 ft-lbs against each of the inner threads of the bolt drain hole. Now consider a replacement bolt that only has 5 threads. If that new bolt is also torqued to 35 ft-lbs, then each one of the 5 threads is exerting a force of 7 ft-lbs.
Or put another way, the new bolt has been torqued to an equivalence of almost 50 ft-lbs instead of the specified 35 ft-lbs. This is computed by the equation (7 / 5) x 35 ft-lbs = 49 ft-lbs.
Remember, the problem is not the steel bolt, but the aluminum oil pan. In order to place the same force on the hole-threads using the shorter new bolt as exerted using the OEM bolt, the new bolt must be torqued only to 25 ft-lbs. This is computed by the equation (5 / 7) x 35 ft-lbs = 25 ft-lbs.
So we lower the torque on the shorter replacement bolt, not to protect the bolt threads (which are steel), but to protect the aluminum threads in the oil pan.
Even Honda follows the above bolt-torque versus thread-count consideration. Consider these Honda OEM drain bolts and torque specifications:
33 ft/lbs - TRANSFER CASE FILL: 20mm x 1.5 x 14mm length – 6.5 threads
33 ft/lbs - TRANSFER CASE DRAIN: 20mm x 1.5 x 14mm length – 6.5 threads
35 ft/lbs - REAR DIFFERENTIAL FILL: 20mm x 1.5 x 16mm length – 7.5 threads
----eof
There are two basic reasons to safety wire a drain plug.
Ř Absolutely prevent the drain plug from falling out. An engine, transmission, differential, etc. just cannot run without oil. And if you accidentally forget to completely tighten the drain plug, the safety wire will still prevent the plug from falling out, even if it may be leaking.
Ř Significantly reduce the wear on aluminum drain-plug threads in any oil pan or oil-sump, by reducing the torque on the drain plug. Safety wire prevents the drain-plug from falling out, even with the reduced torque. Every time a drain plug is removed and replaced, there is a little wear on the aluminum threads in the hole. And it only takes once to over-torque a plug, and strip the threads in the drain hole.
WARNING: do not reduce the torque on any fastener other than the drain plug, ever, never. The manufacturer specified torque on fasteners is what holds things together. Reducing the torque can lead to parts breakage, or a serious accident. But a drain plug is not holding anything together, it is just plugging a drain hole.
Safety wiring a fastener/ drain plug is pretty straight forward. Amateur racers do it all of the time, as it is required, to prevent oiling the track if the drain plug should fall out. Even on a street only driven vehicle, safety wiring can be a good idea.
However, the main problem for first-timers, is finding an appropriate anchor place/ hole to attach the wire from the bolt/ plug. That is the reason for this post, since a proper anchor point will differ for each vehicle and specific fastener.
The FOLLOWING TOPICS are COVERED IN THIS POST
CONSEQUENCES of OIL PAN THREAD DAMAGE:
THE PICTURES SHOWING HOW TO SAFETY WIRE A BOLT:
RULES FOR SAFETY WIRING:
WHAT CAUSES DAMAGE TO DRAIN PLUG-HOLE THREADS?
HOW DIFFICULT IS IT TO SAFETY WIRE A DRAIN PLUG?
WHAT CAN GO WRONG WHEN SAFETY WIRING?
DRILLING THE ANCHOR HOLE:
DRILL BITS AND SAFETY WIRE SIZES:
DRILLING THE DRAIN PLUG:
WIRING THE DRAIN PLUG:
IS IT SAFE TO REDUCE THE OEM TORQUE ON A DRAIN BOLT?
SO WHAT TORQUE SHOULD BE USED ON A DRAIN PLUG
HOW TO GET A CONSISTENT TORQUE READING ON A DRAIN BOLT:
CAN A SEALING WASHER BE REUSED ON A DRAIN BOLT?
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
RDX OEM DRAIN BOLT SIZES:
RDX ALTERNATE DRAIN BOLT CONSIDERATIONS:
Ř THREAD LENGTH CONSIDERATIONS
Ř AN ACCURATE THREAD COUNT
Ř TORQUE CONSIDERATIONS for NON-OEM DRAIN BOLTS
================================================== ==
CONSEQUENCES of OIL PAN THREAD DAMAGE:
Replacing an RDX engine oil pan, because of damaged drain hole threads, can easily cost $1,000 because of the labor involved. The oil pan cannot be dropped without removing/ lowering the RDX front frame cradle (to which the front suspension is attached).
And replacing an RDX case for a transmission, transfer-drive, or differential can cost more than is practical on a 5 year old car. Case replacement requires unit disassembly.
Thread hole repair with a Heli-Coil® is possible, but may not be practical, depending upon the amount of material around the hole. A Heli-Coil® repair is something to consider, if you have a problem with a stripped drain plug hole. A Heli-Coil® repair is a procedure to drill out the damaged hole-threads, and then to insert a coil of steel (new threads) into the original hole. After the original hole has been drilled and re-tapped for the Heli-Coil®, pour 4 quarts of cheap engine oil through the engine, with the drain plug removed. That will (probably) flush-out any aluminum chips in the engine oil-sump, from repairing the drain hole. By the way, Heli-Coil® is only one brand of thread-repair, but has basically become a generic term.
If you doubt that Honda/ Acura engine oil-pans ever have the drain hole threads stripped, there are Honda TSBs out detailing how to do a Heli-Coil® repair on aluminum hole-threads. And there are aftermarket sellers of various repair-procedures for steel Honda engine oil pans.
================================================== ==
THE PICTURES SHOWING HOW TO SAFETY WIRE A BOLT:
************************************************** ******
RULES FOR SAFETY WIRING:
Here is a link to a nice PDF publication on fasteners in general, with a special section (7) on safety wiring. Sorry if this violates any forum rules about posting links.
http://www.airweb.faa.gov/Regulatory...apter%2007.pdf
Here, I have expanded the basic safety wiring rules from the PDF file from the link just above. There are not really that many rules to remember. I have sort of restated the basic rules in different ways, to emphasize that a few basic ideas are really, really, important.
Ř The edges of all safety wire holes should be chamfered or beveled, both the holes in the fastener and the anchor hole. That prevents the edge of the hole from cutting the wire. If the wire is wrapped around a part as an anchor point, the wire should not bear on any sharp edge.
Ř When twisting the wire, hold the two ends at 90 degrees to each other, and at 45 degrees to the run of twisted wire. Use 6 to 8 twists per inch.
Ř Never wire a fastener that is on one part, to an anchor hole on a separate part, unless the two parts are solidly bolted together. There should be no motion between the two parts. Otherwise, the relative motion between the two separate parts will break the safety wire.
Ř Safety wire must be installed so that it tends to pull the fastener tighter, so that the fastener cannot loosen
Ř Install safety wire where practical with the wire wrapped around the head of the bolt, screw, or nut, and positioned so that the loop of the wire fits closely to the contour of the fastener being safety wired. The wire must be twisted so that the loop is held in place, and does not flip up. If there is a clearance problem, the wire may be wrapped over the fastener rather than around it.
Ř Safety wire must not be overstressed. It will break under vibrations if twisted too tight, just tighten it by hand. Do not use pliers to tighten the twists you have made by hand. If your hand twists are too loose, do it over.
Ř Safety wire must be pulled taut when being twisted, and maintain a light tension when secured. If left loose it will break from vibration. You can use pliers to pull it taut after routing through the anchor hole. But only pull on the wire beyond where it will be twisted at the anchor hole. And if it is not taut when complete, you must cut out your work and do it over.
Ř Bend the ends under and inward, when complete, so that you do not poke you eye out, or rip your hand next time you are under the car.
Ř Do not mutilate the twisted section of wire. Use pliers to pull only on the ends, beyond where the wire will be terminated at the anchor hole. Safety wire must not be nicked, kinked, or mutilated. This will cause a weak spot. Mr. Murphy will then cause the wire to break, allowing the drain plug to fall out.
Ř Leave at least 4 to 6 complete twisted turns, after the loop through the anchor hole. That is the pig-tail. You can use pliers in one hand, to help pull the wire taut, and to make the twists at the anchor hole. Cut, do not twist off the excess wire at the end. Use LineMan pliers to make the cut. Regular diagonal pliers will be ruined cutting a double twist of wire. They are OK to cut a single strand of wire.
Ř When removing the safety wire, cut rather than twist the wire to remove it. Cut at both the bolt, and at the anchor hole. Then use pliers to pull it free (you are wearing your safety goggles, right?)
Ř When twisting the wire between the plug head and the anchor hole, if you miscalculate the length, DO NOT untwist the wire to make it fit the space to the anchor hole. You MUST cut out the wire you are working with, and begin again with a new length of wire. Failure to follow this rule will again cause the wire to break, and the plug to fall out. Wire is cheap, your engine is not.
================================================== ====
WHAT CAUSES DAMAGE TO DRAIN PLUG-HOLE THREADS?
If the threads on both the plug and hole are not clean, wear can occur when the drain plug is inserted and torqued. Clean the drain-plug threads every time the plug is removed. Either actually wash and dry the drain bolt, or use brake/ electrical spray cleaner. The drain-hole threads should be clean from the oil draining out, but check anyway.
Each time that a drain plug is torqued into the drain hole, the drain hole threads are stressed. Just as a point of reference, the MID (multifunction indicator display) on my RDX hits 15% every 3800-4000 miles, just like clockwork. In 250K miles that would be over 60 oil changes. But I actually change oil every 2K miles, so that would be a total of over 120 oil changes. Threads eventually wear and fail. How soon they fail depends upon the stress level, or the amount of toque used on the drain plug.
Actually, the real problem is that it only takes once to strip aluminum drain-hole threads. One time at a quickie lube place, the 300 pound ‘mechanic’ tightened the engine oil drain plug in my Chevy 4x4 to over 100 ft-lbs, instead of the specified 18 ft-lbs. Torque that high would have stripped the aluminum drain-hole threads in an RDX.
But the Chevy aluminum oil pan threads were not damaged, because the drain-hole is Heli-Coiled®. That means that stainless-steel threads were OEM inserted into the aluminum pan drain-hole, by GM. So steel drain-plug threads bear against steel drain-hole threads in the oil pan. However, I will note that in this case, the Chevy steel drain-plug head-flange, actually damaged the flat part of the oil pan around the hole. So, exert enough force and anything can be ‘broken’.
Typically, a Heli-Coil® is strong enough that the inserted and torqued bolt will break, before the Heli-Coil® threads in the insertion hole will be damaged, even in an aluminum hole. Too bad Acura did not use Heli-Coils® in the RDX drain-pans.
HOW DIFFICULT IS IT TO SAFETY WIRE A DRAIN PLUG?
The short answer is: “NOT VERY DIFFICULT”. After all, every amateur racing organization, from go-carts to motorcycles to every kind of car racing, requires that the drain plugs be safety wired (as well as a number of other safety related fasteners). If the average 20 year-old can do it, so can you. I suggest that you read a few articles on the internet. You can also simply pay your local machinist to drill the drain plug(s) for you.
Most amateur race groups have posted online articles describing safety-wiring, usually for specific vehicles. That is the reason for this post. Safety-wiring in general is pretty simple. Where people seem to have problems, is finding a proper anchor point, for a particular fastener on a particular vehicle.
WHAT CAN GO WRONG WHEN SAFETY WIRING?
Buy a spare drain plug, and no matter what happens, you still have the original plug. But if you simply drain the oil, then start drilling the drain-plug, well, if you really mess-up the plug, then you are sort of ‘stuck’ aren’t you? Still, likely the only thing wrong with the drain plug is it has a damaged safety-wire hole in it. It still works just fine as a drain plug.
Where you can do serious damage, is when you drill the anchor holes for the plug-wire. There has to be a place to anchor the wire from the drain-plug. Typically, there will not be an already existing place on the engine to anchor the safety-wire from a drain plug.
IF YOU DRILL A HOLE INTO THE PAN OR CASE THAT CAUSES A LEAK, DO NOT BLAME ME. DRILL ONLY THROUGH A CASE STRENGTHENING RIB, NOT INTO THE CASE ITSELF.
DRILLING THE ANCHOR HOLE:
The anchor hole basically has to be drilled into a case structural rib, next to where the drain-plug is installed. For the engine, that means the oil-pan. For the transmission, that means the transmission case (there is no pan). Etc. If possible, it is best to place the anchor hole nearer the edge than the case body.
Look at this picture of the BLAZER ENGINE oil drain plug. Look at both anchor holes. If the rib is too narrow, find another place for the anchor hole.
For example, it might seem like a good anchor hole could be drilled into the lower engine skid plate. But that plate is bolted to the body frame, not the engine. And the engine is mounted on rubber mounts, allowing the engine to move relative to the frame. So the skid plate cannot be used for an anchor hole for the engine drain plug. Besides, you would not want to unwire the drain plug every time you removed the skid plate. So give some thought to just where you will anchor any drain plug.
Do not under any circumstances drill the anchor hole in a part that can move relative to the part with the drain plug hole. Drill the anchor hole at least 1/8 inch, and preferably about 1/4 inch from the edge of the web. Too close to the edge of a structural web, and the hole can crack out to the edge.
Also chamfer (bevel the edge of) the anchor hole slightly. That just means use a 3/16 inch or 1/4 inch drill bit, and counter-sink the 1/16 inch anchor hole. Just a little is necessary, to knock off the sharp edge of the 1/16 inch hole. That will prevent a crack (around the hole) from starting in that aluminum casting that is your oil pan. It will also keep the edge of the anchor hole from cutting and breaking the safety wire. For the same reason, the hole(s) in the bolt head must also be chamfered.
I use a 3/16 inch drill bit to chamfer safety-wire holes, both those in the bolts, and any anchor hole. I turn the drill bit by hand. Yes, by hand, not in a power drill. With a power drill, it is just too easy to mess up an anchor hole in an aluminum rib. Even turning the drill by hand, you can drill too far into aluminum with the larger bit. Remember, you are not drilling a hole, just slightly chamfering the edges of the existing anchor hole. Turning the chamfer bit by hand, will also give you greater access in cramped areas, than will a power drill.
DRILL BITS AND SAFETY WIRE SIZES:
Drill the plug and anchor holes with a 1/16 inch bit. When space is limited, the anchor hole may be drilled with a 3/64 inch bit, but no smaller. Use 0.032 inch diameter 304-type soft (annealed) stainless steel wire. Twist the safety-wire by hand, as I have been doing for 40 years or so. I find that the special twist tool pliers just get in my way.
Use only titanium 1/16 drill bits. An ordinary HS (high-speed) black oxide drill bit will work, but will drill only one bolt-hole, before becoming hopelessly dull. A titanium bit will drill 3-4 holes, so it is actually cheaper if drilling more than one plug. And buy two bits at least, you will probably break the first one. Do not use carbide bits. They are supposedly sharper, but they are also brittle, and you will need to push the drill bit with considerable force against the drain-plug head.
Also, buy a one pound spool of wire. Yes, you can purchase 25-feet of racers-wire from any motorcycle shop. But it takes 2-feet of wire to wire a plug. That is always the case, no matter how short the actual run of wire from the plug to the anchor hole. You need enough extra wire to hold it by hand, and pull it tight. Then clip off the extra wire. It was not wasted, you simply cannot properly wire a plug with less than 2 feet of wire. And beginners will likely need 3 feet, the first time-or-two.
Safety wire can be purchased online or mail-order from Pegasus Racing, or another similar race-shop. I purchased a one pound roll of 0.033 inch 304 wire, from a local tool supplier. One pound of wire is about 300+ feet.
DRILLING THE DRAIN PLUG:
Use masking tape on all of the plug except for the head, especially if the plug has a magnet. This will keep particles off the magnet, and also protect the threads if the drill-bit should slip.
Heat is what dulls the drill bits. A light 10-weight machine oil in the hole (while drilling), will help to cool the bit. And you can only drill about 1/16 inch deep or so, before the drill bit (and bolt) will become hot. Pull back the drill bit, oil the hole, and wait to cool. Or even take the bolt and run cold water over it. Yes, the bolt can get so hot you cannot hold it, while drilling. That will permanently dull the drill bit. Unless you take care, the small 1/16 inch drill bit can be dulled while drilling only 1/8 inch into the bolt. But if you keep the bit cool, a titanium bit can drill 4 holes completely though a bolt head.
If you tighten the plug to exactly the same torque each time, and use the same type of washer (same thickness) each time, the plug head will position within 15 degrees (or less) of rotation, every time. That means that the plug safety wire hole will align in exactly the same spot every time.
If you mark the drain plug with finger-nail polish, while it is properly torqued, you will know exactly which head-flat to drill. If you use different thickness washers, then you may need to drill three rather than one hole in a hex head bolt.
For the RDX transmission and differential drain plugs, you can just drill two through-holes, as there are only four flats (internal). Actually, the easy way is to drill four holes, to make the two through holes. The two holes on opposite sides of the bolt head do not have to align perfectly – they do not on my own drain bolts.
You do not need to drill a 90 degree perfectly aligned hole through the plug head. I do not own a drill press, which would make drilling the bolt much easier. I have a Sears drill-press stand, which holds a hand drill, sort of like a drill press. And I never figured a way to hold the bolt with a vise, as the drain plug head has that shoulder (molded washer ring) on it. So I had to hold the bolt by hand (use gloves), pressed into a piece of heavy Styrofoam on the drill stand base. Just center punch the place you are going to drill, 5 or 6 times to make a really good starting place for the drill bit. Use your goggles while drilling please.
Safety wire drilling jigs are available for hex bolt heads. But they will not work with RDX drain plugs, because of the round washer-sealing flange/ shoulder on the hex head. And the jigs will not work on a round head bolt.
Safety wire holes in a drain plug head must be chamfered/ beveled, so that the sharp edge (of the hole) does not break the safety wire. Just use a larger drill bit to do this.
When drilling, use a 10 weight oil, or machine/ sewing machine oil for lubrication. Remove the drill bit frequently from the hole to remove drilled chips from the hole. If you press too hard, the drill bit will flex, then break. The bit will get really hot, unless you stop every so often. That is the reason for using a titanium bit, it can handle the heat better than any other type of bit.
WIRING THE DRAIN PLUG:
Wear completely side-covering safety goggles, the Lexan kind that are shatter proof. If you do not, sure as hell you will stick the sharp end of the wire into your eye, while twisting the wire, thereby blinding yourself. I do get the occasional scratch on my face, or a hand or wrist. So keep your Tetanus shot up-to-date. I sometimes use the form fitting nitrile gloves, Any other glove will not protect your hands because it rips, or will fit so loosely that you cannot twist the wire. Generally, I do not wear gloves because they do not allow enough control for me. But I do wear a long sleeve shirt, because otherwise, I get many wire scratches on my wrists.
When twisting and routing the safety wire, you MUST NOT touch the wire anywhere between the bolt head and the anchor hole, with anything metal (meaning a set of pliers). Doing so will nick the wire, creating a weak point, which taking into account SOD’s Law, will cause the wire to break, the plug to fall out, your engine to run out of oil, and ensure destruction of the engine before you notice the problem.
Yes, that means you must cut a virgin 2-foot length of wire, and completely safety wire the plug using only your hands, and only pull the wire tight with pliers by pulling only on the very end of the wire, BEYOND THE PIGTAIL, WHERE THE WIRE IS TERMINATED AT THE ANCHOR HOLE.
That is why I find the safety wire pliers useless. Most people do not understand the proper use of these pliers, and inevitably damage the safety wire-run between the plug and anchor hole.
IS IT SAFE TO REDUCE THE OEM TORQUE ON A DRAIN BOLT?
Yes. A drain bolt is just a sealing-plug. It is not holding two parts together. The only concern with a reduced torque, is will there be a leak, and will the bolt fall out? Neither is a concern if safety wire is used.
Never reduce the specified OEM torque on a structural bolt (holding two parts together).
Normally, a bolt is used to clamp two parts together. The clamping force of the bolt, when torqued to specification, is what holds everything together, and also prevents the bolt from loosening. A properly torqued bolt has stretched slightly, and bolt-elastically holds the two parts together, and prevents the bolt from loosening.
SO WHAT TORQUE SHOULD BE USED ON A DRAIN PLUG?
Any reasonable torque on a drain bolt is OK, so long as (1) the washer does not leak, and (2) the bolt does not fall out. 18 or 19 ft-lbs is plenty of torque to seal the washer, especially a copper washer. Actually, I have never had an aluminum washer leak either, when using that torque. And safety wiring the bolt will ensure that the plug does not fall out.
The OEM drain plugs torque on my Chevy 4x4 are specified as either 18 ft-lbs (engine plug with rubber O-ring washer), or 19 ft-lbs (front differential plug with nylon washer).
The actual torque that I use on all RDX drain bolts, is 225 in-lbs, which is 18.75 ft-lbs. I use 225 in-lbs because that is a specific clear marking on my torque wrench.
The only exception is the transmission fill plug. I have reduced the OEM torque from 33 ft-lbs to 25 ft-lbs. The bolt sealing washer is lubricated with transmission fluid before torque. I use 25 ft-lbs instead of 19 ft-lbs, because the transmission fill bolt cannot be safety wired. I use an aluminum washer, and because it galls slightly, that bolt has never loosened. It gives a nice ‘pop’ each time I remove it. I have reused that particular washer about 10 times.
HOW TO GET A CONSISTENT TORQUE READING ON A DRAIN BOLT:
Despite what any mechanic may tell you, a torque wrench is required to get a valid bolt torque. There is simply no way to get an accurate torque setting ‘by-feel’, I do not care how long you have been a mechanic, not at low torque settings (and probably not at high torque settings either).
To prevent galling and to get a very consistent torque, I oil both sides of the sealing-washer. It does not matter what kind of washer I use, I oil it. The oil prevents the washer from galling (sticking), while I am trying to torque the drain plug. Be aware that a bolt with an oiled washer will have the same torque as a bolt with a dry washer, at a reading that is 20% lower. That is, the oiled bolt will read 80 ft-lbs when the dry bolt will read 100 ft-lbs, with exactly the same amount of force on the torque wrench. Except that you will be lucky to get a consistent and valid torque with the dry bolt and washer.
Also, check that both the bolt shoulder and washer are clean, especially if you are reusing the washer. Simply press the oiled washer against the bolt sealing surface. Then twist (rotate) the washer back and forth with your fingers, feeling for any grittiness. It should feel perfectly smooth. Check both sides of the washer against the bolt shoulder, before installation. And wipe clean the case sealing surface, around the hole.
Under even low torque (pressure), a dry aluminum washer will gall. The word gall means “to cold-weld”, and that is exactly what the washer does – it spot welds itself to the aluminum pan (and the drain bolt head). That is why a drain plug installed with a dry washer typically requires much more effort to remove, than it did to tighten. Galling is much less of a problem with a copper or nylon washer.
Do not use a 100 ft-lb torque wrench to torque drain bolts on your RDX, and definitely not a 150 ft-lb wrench. You should be aware that a torque wrench is not accurate at the lower 20% and the upper 20% of the torque range. That means that a torque wrench with a maximum range of 50 ft-lbs, is not accurate below 10 ft-lbs or above 40 ft-lbs. That means that a 100 ft-lbs torque wrench is not accurate below 20 ft-lbs or above 80 ft-lbs. This is why I also have a torque wrench for very low torque that reads only to 12 ft-lbs (150 in-lbs).
An inexpensive beam-type torque-wrench is only around $20-30 and some are 2% accurate which is about as close as you will be able to read the wrench markings anyway. By the way, that is 2% of the total reading of the wrench. For a 150 ft-lb wrench that means even the lowest reading is accurate only to +/- 3 ft-lbs = 2% of 150.
CAN A SEALING WASHER BE REUSED ON A DRAIN BOLT?
I reuse copper and nylon washers once-or-twice. With the low torque I am using, an aluminum washer can sometimes also be reused once.
Hand tighten the bolt, until the washer is snug against the case. Then tighten the bolt with a torque wrench. Judge whether a washer can be reused, by how many degrees of bolt rotation are required to get a valid torque. If the washer has been crushed after multiple uses, only a few degrees of rotation of the bolt will be required to get the torque you are using. It is very difficult to get a consistent/ valid torque, if the bolt only moves 10 or 15 degrees of rotation, from zero to full torque. In that case, use a new washer.
A new washer, whether aluminum or copper, generally requires less than 45 degrees or 1/8 turn of bolt rotation, for a proper 19 ft-lb torque. That is an approximation. Many factors are involved, so use a torque wrench.
RDX drain bolts are large bolts (with a large washer). Honda specifies a high drain-bolt torque because of the large solid aluminum washer. Aluminum requires a lot of force to crush, if not to seal. An aluminum washer is much harder than a copper or nylon washer. The crush is to prevent the plug from loosening, not to seal.
Trying to reuse an aluminum washer, once it has been crushed, it will be difficult to get a consistent torque. That is why a new aluminum washer is supposed to be used for each oil change. However, if a lower than OEM torque is used, an aluminum washer may possibly be re-used once or twice.
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
Then there is no need to drill it yourself for safety wire. Any Honda (after the late ‘80s) or Acura uses the same engine oil drain plug: 14mm diameter x 1.5mm thread pitch. There are many online sites selling an engine oil drain plug, that is already drilled for safety wiring.
Plugs are available in aluminum, steel, and titanium. If the plug has a magnet, buy only a steel plug. Otherwise, only the glue is holding that magnet in place, and glue has been know to fail. That would allow the magnet to stick to some undesirable internal moving part and cause damage. Steel plugs with a magnet are OK, because the magnet is going to continue sticking to the drain plug if the glue fails.
But you can also purchase an aluminum drain plug without a magnet, although I have not seen any that are already drilled. The only drilled aluminum drain plugs that I have seen have magnets. Aluminum is MUCH easier to drill for safety wiring, than steel.
The problem with a pre-drilled plug is that the safety wire hole may not be in the position that is needed, when the plug is properly torqued. Look at the pictures in this post, and note that some of the drain plugs have two holes. Note that for the engine drain plugs, only one hole position is appropriate. Also, if you switch between washers of different thicknesses (aluminum/ copper), the drilled safety wire hole will position differently for the same bolt torque.
RDX OEM DRAIN BOLT SIZES:
The length given in the table below, is the length under the bolt head to the end of the bolt. It is NOT the thread length. What is the significance of the number of threads on each plug? See the next section. The thread count below considers only fully formed threads. And disregards whether or not the bolt thread can actually engage the internal threads inside the drain hole. Again, see the following sections for further explanation.
ENGINE OIL PAN:.............. 14mm x 1.5 x 15mm length – 7.5 threads
TRANSFER CASE DRAIN AND FILL: 20mm x 1.5 x 14mm length - 6.5 threads
REAR DIFFERENTIAL FILL:...... 20mm x 1.5 x 16mm length – 7.5 threads
REAR DIFFERENTIAL DRAIN:..... 18mm x 1.5 – 5.5 threads
TRANSMISSION DRAIN:.......... 18mm x 1.5 – 5.5 threads
The transmission drain plug, and the rear differential drain plug, are the same part number (same plug). The end (tip) of these plugs has no threads, with the magnet (inserted into) the end of these plugs. The magnet is crimped or swaged in place, no sign of glue. The magnet is 15.5mm Length x 6mm Diameter.
RDX ALTERNATE DRAIN BOLT CONSIDERATIONS:
If using a non-OEM drain plug, consider the length of the new plug. This will be important if replacing an OEM plug with a magnetic one, or with a different head style. If the alternate bolt length is longer, is there room inside the case, without hitting some interior part? Is there room for a magnet on the end of the new plug, to project into the case, without hitting something?
Is the alternate drain plug shorter than the OEM plug? Are there enough threads on the shorter plug to achieve an acceptable torque value, without stripping the threads in the drain hole?
THREAD LENGTH CONSIDERATIONS:
How can a bolt have 1/2-thread? Look at the bolt from the side, then count the threads along-side each edge. Count only threads which are fully formed, and of full height. If the count differs by one, from one side of the bolt to the other, then one full-height thread only circles one-half of the bolt. That makes half-a-thread. The half thread will be either just under the bolt head, or at the end/ tip, or both.
AN ACCURATE THREAD COUNT:
Place the proper washer onto the drain bolt. Any thread which is closer to the washer, than the distance between two threads, should not be counted. That is because the bolt drain hole is counter-sunk/ chamfered. That is, the threads inside the bolt hole do not extend completely to the edge of the hole opening. Therefore, there is no inner hole-thread to engage with the bolt-thread nearest the bolt head. Sometimes, the bolt thread just under the head, can be forced to engage a thread inside the hole, by using a thinner washer. Copper washers are generally half the thickness of aluminum washers.
Consider both the Transmission and Rear Differential drain plugs (same plug/ same Acura part number). The drain plug has 5.5 threads, but with an OEM aluminum sealing washer installed, only 5 full-threads can engage with the threads inside the drain hole.
Any bolt thread which is not the same “full-height” as all other threads, will not fully engage the threads inside the drain hole. Examine the threads on a drain bolt carefully. Is the thread just under the bolt head, or at the end of the bolt, fully formed? Is it the same height as the other threads, with a sharp edge, or lower with a rounded edge? Is this thread fully separate, or partly machined into the area near the bolt end/ tip? Any condition which prevents a bolt thread from fully engaging with the drain hole threads, means that this bolt thread is not supporting the full force of the bolt torque, or even no force at all.
Finally, look at the threads inside the bolt drain hole. If the bolt has 7 threads, but there are only 6 threads inside the bolt hole, then only a maximum of 6 bolt threads can engage. This should be taken into account when replacing an OEM bolt, in determining a proper bolt length.
TORQUE CONSIDERATIONS for ALTERNATE DRAIN BOLTS:
If an OEM bolt has 7 threads, and has a torque specification of 35 ft-lbs, then each bolt thread is exerting a force of 5 ft-lbs against each of the inner threads of the bolt drain hole. Now consider a replacement bolt that only has 5 threads. If that new bolt is also torqued to 35 ft-lbs, then each one of the 5 threads is exerting a force of 7 ft-lbs.
Or put another way, the new bolt has been torqued to an equivalence of almost 50 ft-lbs instead of the specified 35 ft-lbs. This is computed by the equation (7 / 5) x 35 ft-lbs = 49 ft-lbs.
Remember, the problem is not the steel bolt, but the aluminum oil pan. In order to place the same force on the hole-threads using the shorter new bolt as exerted using the OEM bolt, the new bolt must be torqued only to 25 ft-lbs. This is computed by the equation (5 / 7) x 35 ft-lbs = 25 ft-lbs.
So we lower the torque on the shorter replacement bolt, not to protect the bolt threads (which are steel), but to protect the aluminum threads in the oil pan.
Even Honda follows the above bolt-torque versus thread-count consideration. Consider these Honda OEM drain bolts and torque specifications:
33 ft/lbs - TRANSFER CASE FILL: 20mm x 1.5 x 14mm length – 6.5 threads
33 ft/lbs - TRANSFER CASE DRAIN: 20mm x 1.5 x 14mm length – 6.5 threads
35 ft/lbs - REAR DIFFERENTIAL FILL: 20mm x 1.5 x 16mm length – 7.5 threads
----eof
06-14-2012, 08:17 PM
#2
Burning Brakes
Thread Starter
ENGINE Drain Plug
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
Yes, that is a copper washer in the picture above.
RDX OEM ENGINE DRAIN BOLT SIZE:
The length given below, is the length under the bolt head to the end of the bolt. It is NOT the thread length. The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole.
ENGINE OIL PAN:.............. 14mm x 1.5 x 15mm length – 7.5 threads
ANCHOR HOLE for RDX ENGINE DRAIN BOLT:
There is often no direct path from the drain plug to the anchor hole, in the plane of the bolt head. If this were a racing vehicle, the anchor hole would be drilled into the oil pan web in the same plane (in-line) with the drain bolt head. The safety wire would be wrapped under and then over the oil pan projection to the upper right of the bolt head in the picture above. It would not matter that the wire would be pressing against the projection on the oil pan.
But this is a street driven vehicle. There is simply no point to which to anchor the safety wire, without the wire rubbing against the oil pan, other than the one shown in the picture. And I did not want the safety wire rubbing a hole in the oil pan, over 20 years.
There is an alternate anchor hole shown in the picture above. Unfortunately, the alternate hole would force the safety wire against the oil pan. So a second anchor hole was drilled, the one actually used in the picture above.
DRILLING THE RDX ENGINE DRAIN BOLT:
The RDX drain plug picture shows a non-optimal but perfectly adequate position for the safety wire, on the bolt head. But there is no hole in the flat of the drain plug, that would be in the best position. Someday I will have to take the time to drill a third hole into my own RDX engine drain plug head.
Because of the wire angle, the safety wire cannot be partially wrapped around the bolt head, as is common. So it is wrapped over the top of the bolt head. And that means that there is only one hole in the drain-plug head that is optimally positioned. So either you must check position before drilling the plug, or else drill 3 bolt-holes, so that there is always one bolt-hole in the optimal position.
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
Then there is no need to drill it yourself for safety wire. Any Honda (after the late ‘80s) or Acura uses the same size engine drain bolt. Pre-drilled bolts are readily available. Look for one with multiple drilled holes.
But most drain bolts I have seen have only one drilled hole. And that single hole is unlikely to be positioned properly when the drain bolt is torqued into the RDX oil pan. See comments above.
KEEP DRAIN PLUGS SHINNY and PREVENT RUST:
With a Q-tip, smear some Tune-up (silicone) grease on the drain plug, after torque and wiring it up. Just be sure to wipe off the grease next time you drain the oil, before removing the plug. Silicone grease under the bolt head or on the washer will really mess-up the torque reading, and possibly cause you to over-torque and strip the pan threads.
Buy the 3-ounce size. It is 9-times larger than the small 1/3 ounce tubes for only twice the price, around $6-7 for the 3-ounce size. There are lots of other uses for silicone grease.
----eof
Yes, that is a copper washer in the picture above.
RDX OEM ENGINE DRAIN BOLT SIZE:
The length given below, is the length under the bolt head to the end of the bolt. It is NOT the thread length. The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole.
ENGINE OIL PAN:.............. 14mm x 1.5 x 15mm length – 7.5 threads
ANCHOR HOLE for RDX ENGINE DRAIN BOLT:
There is often no direct path from the drain plug to the anchor hole, in the plane of the bolt head. If this were a racing vehicle, the anchor hole would be drilled into the oil pan web in the same plane (in-line) with the drain bolt head. The safety wire would be wrapped under and then over the oil pan projection to the upper right of the bolt head in the picture above. It would not matter that the wire would be pressing against the projection on the oil pan.
But this is a street driven vehicle. There is simply no point to which to anchor the safety wire, without the wire rubbing against the oil pan, other than the one shown in the picture. And I did not want the safety wire rubbing a hole in the oil pan, over 20 years.
There is an alternate anchor hole shown in the picture above. Unfortunately, the alternate hole would force the safety wire against the oil pan. So a second anchor hole was drilled, the one actually used in the picture above.
DRILLING THE RDX ENGINE DRAIN BOLT:
The RDX drain plug picture shows a non-optimal but perfectly adequate position for the safety wire, on the bolt head. But there is no hole in the flat of the drain plug, that would be in the best position. Someday I will have to take the time to drill a third hole into my own RDX engine drain plug head.
Because of the wire angle, the safety wire cannot be partially wrapped around the bolt head, as is common. So it is wrapped over the top of the bolt head. And that means that there is only one hole in the drain-plug head that is optimally positioned. So either you must check position before drilling the plug, or else drill 3 bolt-holes, so that there is always one bolt-hole in the optimal position.
WHAT ABOUT AN AFTERMARKET PRE-DRILLED DRAIN PLUG?
Then there is no need to drill it yourself for safety wire. Any Honda (after the late ‘80s) or Acura uses the same size engine drain bolt. Pre-drilled bolts are readily available. Look for one with multiple drilled holes.
But most drain bolts I have seen have only one drilled hole. And that single hole is unlikely to be positioned properly when the drain bolt is torqued into the RDX oil pan. See comments above.
KEEP DRAIN PLUGS SHINNY and PREVENT RUST:
With a Q-tip, smear some Tune-up (silicone) grease on the drain plug, after torque and wiring it up. Just be sure to wipe off the grease next time you drain the oil, before removing the plug. Silicone grease under the bolt head or on the washer will really mess-up the torque reading, and possibly cause you to over-torque and strip the pan threads.
Buy the 3-ounce size. It is 9-times larger than the small 1/3 ounce tubes for only twice the price, around $6-7 for the 3-ounce size. There are lots of other uses for silicone grease.
----eof
07-06-2012, 12:41 AM
#3
Burning Brakes
Thread Starter
Safety Wire an ENGINE OIL FILTER
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
If you are going to safety wire the drain plug, you will also want to safety wire the Oil Filter.
1) Purchase an oil filter with an integral drilled place to put the safety wire. K&N brand makes such filters, and there are other specialty brands out there.
2) But safety wiring an ordinary oil filter is not that difficult, by using a large hose clamp. Racers of various sorts do it all the time: car, motorcycle, go-cart, etc.
================================================== ==
THE K&N BRAND RDX OIL FILTER:
I use this filter because I think it is a good filter, but I do not endorse any brand. Choose your own brand of filter. This is basically the same filter as a Mobil-1 filter, but costs a buck more for the welded on drilled nut for safety wire. It is worth a buck to me, as you will see the extra effort required to safety wire a normal oil filter with a hose clamp.
PICTURE: K&N oil filter
The K&N filter should be installed 3/4-turn or maybe 1-turn, check on the filter label. So I use a sharp punch or carbide-tipped marker to scrape an arrow-head on the bottom of the filter, so that when it has been installed 3/4-turn, the arrow-head points to the front of the car, as shown in the picture.
THE MOBIL-1 BRAND RDX OIL FILTER:
The Mobil-1 110 oil filter is about 65mm (2.5in) in diameter. A hose clamp with a maximum OD of about 70mm is required.
The scraped arrow-point mark on the bottom of the oil filter, is there to ensure turning the filter exactly the correct amount during installation, and to easily tell if the filter begins to loosen.
The RED paint-mark on the CLAMP-STRAP/ filter is there to easily tell if the clamp begins to slip around the oil filter.
PICTURE: Mobil-1 oil filter
Decide how tight to tighten the hose clamp, before installing the oil filter on the vehicle. Tighten the clamp until you cannot turn the hose clamp by hand around the filter. Then mark the CLAMP-BOLT with red finger-nail polish. Then, when the filter is installed on the car, tighten until your mark is reached. You do not want to collapse the end of the oil filter with the clamp.
PICTURE: Mobil-1 oil filter Clamp
A local specialty hose-supplier is a good place to find a toggle-bolt hose clamp, or possibly a motorcycle dealer/ parts shop. A 70mm maximum size toggle-bolt hose clamp is used in the picture above. The next size smaller clamp that I could find was too small. But the 70mm size required shortening the threaded end of the bolt. A cut-off wheel is best, but I just used a hack-saw, and then cleaned-up the end with a small file. Wrap the threaded end with several wraps of masking tape, to prevent damaging the other threads.
A toggle bolt hose clamp uses a self-locking nut with a nylon (or fiber) insert, to tighten the clamp. If you are willing to spend about $5 for this type clamp, instead of $1 for the regular screw-kind, the toggle bolt hose clamp itself does not require safety wiring (or silicone sealer to lock the clamp screw). However, after using the clamp 5 to 10 times, the nylock nut should be replaced, as the nylon nut-lock insert will wear.
A nylock nut should not be used when the temperature is more than 250 degrees F, but use an all metal locking nut instead. Since the oil inside the engine should not get this hot, neither should a hose clamp on the outside of the oil filter. Anyway, an all metal locking nut is available, and can be used, if you are really concerned about the high temperature allowing the nylock locking nut to loosen.
I personally prefer the toggle bolt hose clamp style, because it applies a more even (equal) force around the circumference of the oil filter. Note that the regular style of hose clamp has a ‘bulge’ under the screw housing. That is not a problem with a rubber hose. But you do not want that metal hose clamp bulge digging into the side of the thin metal shell of the oil filter.
You must use some care, not to collapse the end of the oil filter, with any hose clamp. But too loose and the clamp will not hold the filter in place. This is especially of some concern, since the hose clamp cannot be used on the smooth base of the filter, where the force would be more evenly distributed. But because of the RDX filter housing, the clamp must be used on the fluted/ faceted end of the filter.
If the hose clamp should collapse (round-off) the facets on the end of the filter, so that a corresponding filter wrench cannot be used to remove the filter, all is not lost. The mechanic at my local Acura dealer does not use a filter wrench anyway. He uses either slip ring pliers, or those special filter pliers which are similar, with special teeth to bite into the filter case. He just grabs the end of the filter, and twists it loose.
If using a screw-type hose clamp, position the screw housing between two flutes on the filter. That will not only help prevent crushing a flute, but will also help to prevent the clamp from slipping on the filter.
THE RIGHT WAY AND THE WRONG WAY TO USE A HOSE CLAMP to SECURE AN OIL FILTER:
You simply need an ordinary hose clamp to safety wire any screw-on oil filter. But there is a right way and a wrong way to wire the hose clamp.
PICTURE: wrong-way
The above is WRONG, unless that filter screws on (tightens) counter-clockwise. The safety wire is pulling the filter loose, not tight (clock-wise), as required. The picture is “borrowed” from the web, and is an indication that not everything you read on the web is correct.
However, do note that the wire is looped through only one side of the clamp screw housing. Do not try to loop the wire around the entire screw-housing – it will slip off.
PICTURE: correct-way
The above is the CORRECT way to wire an oil filter, with one small caveat. The hose clamp itself is not safety wired. There is no point in going to this trouble if the hose clamp is allowed to loosen.
It is possible to safety-wire a hose clamp. But there is an easier way. Simply force a glob of silicone sealer (clear) under the head of the screw, into the clamp screw-slots and the screw threads. To remove the clamp, just apply a bit more force to loosen the screw, with your screwdriver.
AN ADDITIONAL INVENTIVE WAY TO SAFETY WIRE AN OIL FILTER:
The next set of pictures shows an inventive way to wire an oil filter, when there is no nearby place to drill an anchor hole. You may find this useful for another vehicle, or another item that needs safety-wiring.
But again, the filter is being pulled loose (counter-clockwise) by the safety wire – WRONG. The filter should be pulled tight (clockwise) by the safety wire. By the way, that orange stuff is silicone seal, used to prevent the flat-head screws from loosening. It would be better if the screws were safety wired, like the flat head screw wired to the oil filter.
PICTURE: no handy anchor hole
If you are wondering how to drill the flat head inset-hex screw, a Dremel tool (and steady hand) works well.
PICTURE: drilling an internal-hex bolt
************************************************** ******
----eof
If you are going to safety wire the drain plug, you will also want to safety wire the Oil Filter.
1) Purchase an oil filter with an integral drilled place to put the safety wire. K&N brand makes such filters, and there are other specialty brands out there.
2) But safety wiring an ordinary oil filter is not that difficult, by using a large hose clamp. Racers of various sorts do it all the time: car, motorcycle, go-cart, etc.
================================================== ==
THE K&N BRAND RDX OIL FILTER:
I use this filter because I think it is a good filter, but I do not endorse any brand. Choose your own brand of filter. This is basically the same filter as a Mobil-1 filter, but costs a buck more for the welded on drilled nut for safety wire. It is worth a buck to me, as you will see the extra effort required to safety wire a normal oil filter with a hose clamp.
PICTURE: K&N oil filter
The K&N filter should be installed 3/4-turn or maybe 1-turn, check on the filter label. So I use a sharp punch or carbide-tipped marker to scrape an arrow-head on the bottom of the filter, so that when it has been installed 3/4-turn, the arrow-head points to the front of the car, as shown in the picture.
THE MOBIL-1 BRAND RDX OIL FILTER:
The Mobil-1 110 oil filter is about 65mm (2.5in) in diameter. A hose clamp with a maximum OD of about 70mm is required.
The scraped arrow-point mark on the bottom of the oil filter, is there to ensure turning the filter exactly the correct amount during installation, and to easily tell if the filter begins to loosen.
The RED paint-mark on the CLAMP-STRAP/ filter is there to easily tell if the clamp begins to slip around the oil filter.
PICTURE: Mobil-1 oil filter
Decide how tight to tighten the hose clamp, before installing the oil filter on the vehicle. Tighten the clamp until you cannot turn the hose clamp by hand around the filter. Then mark the CLAMP-BOLT with red finger-nail polish. Then, when the filter is installed on the car, tighten until your mark is reached. You do not want to collapse the end of the oil filter with the clamp.
PICTURE: Mobil-1 oil filter Clamp
A local specialty hose-supplier is a good place to find a toggle-bolt hose clamp, or possibly a motorcycle dealer/ parts shop. A 70mm maximum size toggle-bolt hose clamp is used in the picture above. The next size smaller clamp that I could find was too small. But the 70mm size required shortening the threaded end of the bolt. A cut-off wheel is best, but I just used a hack-saw, and then cleaned-up the end with a small file. Wrap the threaded end with several wraps of masking tape, to prevent damaging the other threads.
A toggle bolt hose clamp uses a self-locking nut with a nylon (or fiber) insert, to tighten the clamp. If you are willing to spend about $5 for this type clamp, instead of $1 for the regular screw-kind, the toggle bolt hose clamp itself does not require safety wiring (or silicone sealer to lock the clamp screw). However, after using the clamp 5 to 10 times, the nylock nut should be replaced, as the nylon nut-lock insert will wear.
A nylock nut should not be used when the temperature is more than 250 degrees F, but use an all metal locking nut instead. Since the oil inside the engine should not get this hot, neither should a hose clamp on the outside of the oil filter. Anyway, an all metal locking nut is available, and can be used, if you are really concerned about the high temperature allowing the nylock locking nut to loosen.
I personally prefer the toggle bolt hose clamp style, because it applies a more even (equal) force around the circumference of the oil filter. Note that the regular style of hose clamp has a ‘bulge’ under the screw housing. That is not a problem with a rubber hose. But you do not want that metal hose clamp bulge digging into the side of the thin metal shell of the oil filter.
You must use some care, not to collapse the end of the oil filter, with any hose clamp. But too loose and the clamp will not hold the filter in place. This is especially of some concern, since the hose clamp cannot be used on the smooth base of the filter, where the force would be more evenly distributed. But because of the RDX filter housing, the clamp must be used on the fluted/ faceted end of the filter.
If the hose clamp should collapse (round-off) the facets on the end of the filter, so that a corresponding filter wrench cannot be used to remove the filter, all is not lost. The mechanic at my local Acura dealer does not use a filter wrench anyway. He uses either slip ring pliers, or those special filter pliers which are similar, with special teeth to bite into the filter case. He just grabs the end of the filter, and twists it loose.
If using a screw-type hose clamp, position the screw housing between two flutes on the filter. That will not only help prevent crushing a flute, but will also help to prevent the clamp from slipping on the filter.
THE RIGHT WAY AND THE WRONG WAY TO USE A HOSE CLAMP to SECURE AN OIL FILTER:
You simply need an ordinary hose clamp to safety wire any screw-on oil filter. But there is a right way and a wrong way to wire the hose clamp.
PICTURE: wrong-way
The above is WRONG, unless that filter screws on (tightens) counter-clockwise. The safety wire is pulling the filter loose, not tight (clock-wise), as required. The picture is “borrowed” from the web, and is an indication that not everything you read on the web is correct.
However, do note that the wire is looped through only one side of the clamp screw housing. Do not try to loop the wire around the entire screw-housing – it will slip off.
PICTURE: correct-way
The above is the CORRECT way to wire an oil filter, with one small caveat. The hose clamp itself is not safety wired. There is no point in going to this trouble if the hose clamp is allowed to loosen.
It is possible to safety-wire a hose clamp. But there is an easier way. Simply force a glob of silicone sealer (clear) under the head of the screw, into the clamp screw-slots and the screw threads. To remove the clamp, just apply a bit more force to loosen the screw, with your screwdriver.
AN ADDITIONAL INVENTIVE WAY TO SAFETY WIRE AN OIL FILTER:
The next set of pictures shows an inventive way to wire an oil filter, when there is no nearby place to drill an anchor hole. You may find this useful for another vehicle, or another item that needs safety-wiring.
But again, the filter is being pulled loose (counter-clockwise) by the safety wire – WRONG. The filter should be pulled tight (clockwise) by the safety wire. By the way, that orange stuff is silicone seal, used to prevent the flat-head screws from loosening. It would be better if the screws were safety wired, like the flat head screw wired to the oil filter.
PICTURE: no handy anchor hole
If you are wondering how to drill the flat head inset-hex screw, a Dremel tool (and steady hand) works well.
PICTURE: drilling an internal-hex bolt
************************************************** ******
----eof
07-06-2012, 09:18 PM
#4
Burning Brakes
Thread Starter
How to Safety Wire a TRANSMISSION Drain Plug:
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
1) Because I use a lower than OEM torque, I am not worried about stressing the drain hole threads (no matter how many times the oil is drained). And I change my own oil so that I do not worry about the dealer mechanic over-torquing the drain plug.
2) And because I safety-wire the drain plug, I am not worried about the drain plug falling out.
If the transmission oil drain hole is damaged, there is no ‘pan’ to replace. The transmission case must be replaced. And replacing a case for an RDX transmission is not practical, the entire transmission must be replaced with a rebuilt unit. Or perhaps thread hole repair with a Heli-Coil® is possible, but may not be practical, depending upon the amount of metal around the drain plug hole. A Heli-Coil® repair is something to consider, if you have a problem with any stripped drain plug hole.
NOTE: the safety-wire hole in the drain plug that is closest to the anchor hole was not used, because that would not allow enough room to bend the twisted wire into place, to attach at the anchor hole.
NOTE: the next picture shows the safety-wire beginning at the anchor hole, rather than at the drain plug hole, as in the previous pictures. I find this plug so difficult to wire that I have tried both ways. Neither is easy. It usually takes me 3 or 4 times to get it right. And yes, I always safety wire the plug, even if I am doing a 4x3 drain, and plan to drain the oil again 50 miles later, or the next day.
And if you are wondering why the red mark on the drain-bolt is positioned differently in the last picture, versus the first three pictures, the first pics show a copper washer and the last pic shows an aluminum washer (different washer thicknesses). The torque was the same in both cases.
Neither type of washer has ever leaked or dripped, nor the plug loosened.
NOTE: the dirt on the plug is mostly because the plug is coated with silicone (dielectric) grease. And that is why there is no corrosion on the plug.
RDX OEM TRANSMISSION DRAIN BOLT SIZE:
The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole. I torque these bolts to 225 in-lbs or 19 ft-lbs.
TRANSMISSION DRAIN:.......... 18mm x 1.5 – 5.5 threads
REAR DIFFERENTIAL DRAIN:..... 18mm x 1.5 – 5.5 threads
The transmission drain plug, and the rear differential drain plug, are the same part number (same plug). The end (tip) of these plugs has no threads, with the magnet (inserted into) the end of these plugs. The magnet is crimped or swaged in place, no sign of glue. The magnet is 15.5mm Length x 6mm Diameter, and is a ceramic type, black in color.
WHAT ABOUT THE TRANSMISSION FILL PLUG?
Well, there is no practical way to safety wire the fill plug. OK, if you were willing to remove the air filter box every time, then maybe. But I am not willing to do that. Or if I were filling the trans through the dip-stick tube, then I would wire the fill-plug and never remove it. But I can remove the fill plug in 5 minutes now (lots of practice) and dump in 4 quarts of oil in 10 more minutes. I personally have never found a practical way to fill 4-quarts through the dip-stick tube. The most I have done is 2-4 ounces, for top-up after a drain and fill.
So I have just reused the same OEM aluminum washer on the fill plug, for 14 times now. I torque to 25 ft-lbs with an ATF lubed washer. It has never loosened, and I suppose that I am thinking that if it ever does loosen, it is unlikely to fall out before I notice. I check it every time I check the oil – once per week. I just look at the position of the ATF lettering on the top of the bolt, to determine if it has moved.
OPTIONAL FILL PLUG WASHER:
If you do feel that you want to use a new fill plug washer every time, a cheaper alternative to the $5 Acura OEM aluminum washer, is Toyota p/n 90430-24003 copper washer which fits a 2005 4runner front differential, and costs $1.74 last time I checked. The OEM Toyota torque for the bolt that uses this washer is 48 ft-lbs.
I have a Toyota washer myself, but have never used it. It is there in case I drop the OEM RDX washer, and if you should do so, you probably will not be able to find and recover it.
----eof
1) Because I use a lower than OEM torque, I am not worried about stressing the drain hole threads (no matter how many times the oil is drained). And I change my own oil so that I do not worry about the dealer mechanic over-torquing the drain plug.
2) And because I safety-wire the drain plug, I am not worried about the drain plug falling out.
If the transmission oil drain hole is damaged, there is no ‘pan’ to replace. The transmission case must be replaced. And replacing a case for an RDX transmission is not practical, the entire transmission must be replaced with a rebuilt unit. Or perhaps thread hole repair with a Heli-Coil® is possible, but may not be practical, depending upon the amount of metal around the drain plug hole. A Heli-Coil® repair is something to consider, if you have a problem with any stripped drain plug hole.
NOTE: the safety-wire hole in the drain plug that is closest to the anchor hole was not used, because that would not allow enough room to bend the twisted wire into place, to attach at the anchor hole.
NOTE: the next picture shows the safety-wire beginning at the anchor hole, rather than at the drain plug hole, as in the previous pictures. I find this plug so difficult to wire that I have tried both ways. Neither is easy. It usually takes me 3 or 4 times to get it right. And yes, I always safety wire the plug, even if I am doing a 4x3 drain, and plan to drain the oil again 50 miles later, or the next day.
And if you are wondering why the red mark on the drain-bolt is positioned differently in the last picture, versus the first three pictures, the first pics show a copper washer and the last pic shows an aluminum washer (different washer thicknesses). The torque was the same in both cases.
Neither type of washer has ever leaked or dripped, nor the plug loosened.
NOTE: the dirt on the plug is mostly because the plug is coated with silicone (dielectric) grease. And that is why there is no corrosion on the plug.
RDX OEM TRANSMISSION DRAIN BOLT SIZE:
The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole. I torque these bolts to 225 in-lbs or 19 ft-lbs.
TRANSMISSION DRAIN:.......... 18mm x 1.5 – 5.5 threads
REAR DIFFERENTIAL DRAIN:..... 18mm x 1.5 – 5.5 threads
The transmission drain plug, and the rear differential drain plug, are the same part number (same plug). The end (tip) of these plugs has no threads, with the magnet (inserted into) the end of these plugs. The magnet is crimped or swaged in place, no sign of glue. The magnet is 15.5mm Length x 6mm Diameter, and is a ceramic type, black in color.
WHAT ABOUT THE TRANSMISSION FILL PLUG?
Well, there is no practical way to safety wire the fill plug. OK, if you were willing to remove the air filter box every time, then maybe. But I am not willing to do that. Or if I were filling the trans through the dip-stick tube, then I would wire the fill-plug and never remove it. But I can remove the fill plug in 5 minutes now (lots of practice) and dump in 4 quarts of oil in 10 more minutes. I personally have never found a practical way to fill 4-quarts through the dip-stick tube. The most I have done is 2-4 ounces, for top-up after a drain and fill.
So I have just reused the same OEM aluminum washer on the fill plug, for 14 times now. I torque to 25 ft-lbs with an ATF lubed washer. It has never loosened, and I suppose that I am thinking that if it ever does loosen, it is unlikely to fall out before I notice. I check it every time I check the oil – once per week. I just look at the position of the ATF lettering on the top of the bolt, to determine if it has moved.
OPTIONAL FILL PLUG WASHER:
If you do feel that you want to use a new fill plug washer every time, a cheaper alternative to the $5 Acura OEM aluminum washer, is Toyota p/n 90430-24003 copper washer which fits a 2005 4runner front differential, and costs $1.74 last time I checked. The OEM Toyota torque for the bolt that uses this washer is 48 ft-lbs.
I have a Toyota washer myself, but have never used it. It is there in case I drop the OEM RDX washer, and if you should do so, you probably will not be able to find and recover it.
----eof
07-07-2012, 05:33 PM
#5
Burning Brakes
Thread Starter
How to Safety Wire a RADIATOR Drain Plug
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
If the radiator drain plug falls out, the engine will overheat and probably be permanently damaged. That is unlikely. But I prefer to think in terms of the results of what can happen, rather than the likely-hood that nothing bad will happen. Something bad always happens to somebody – I prefer that it is not me.
NOTE: the drain plug has no washer, like on an oil drain-plug, but instead a tiny sealing O-ring on the plug tip. I would suggest that this O-ring be replaced each time the radiator fluid is flushed, especially if you wait the 5-years between flushes. Rubber does deteriorate from heat and water and chemicals (radiator coolant). When re-installing the drain plug, the O-ring should be lubricated – see below.
NOTE: there is (or was) a factory paint mark on your radiator drain plug. You can use this mark to check that the drain plug is not coming loose, by looking at the mark at every oil change. And if the factory mark is missing, you can add your own mark as in the next picture. You can add you own paint mark through the existing slot in the Front Bumper Cover.
Such a mark will also tell you how tight to install the drain plug after you perform a drain-and-fill of coolant. Since all parts are plastic, it is helpful to know just how tight to replace the drain plug without breaking something, and so that the drain plug does not leak.
NOTE: a transmission aftermarket inline filter has been added in these pictures of the radiator drain plug safety-wiring. That is why the pictures look slightly different from your stock RDX.
Safety wiring the radiator drain plug requires removal of the front Splash Guard, which is located between the front bumper cover, and the front frame cradle, in front of the engine oil pan. For tips on removing the Splash Guard, look at my post for adding a Power Steering inline filter, about half way down the post..
LINK to: DIY – Add a Power Steering Replaceable Inline Magnetic Filter
https://acurazine.com/forums/showthread.php?t=828859
WIRING THE RADIATOR DRAIN PLUG:
Since the radiator is plastic, and the drain plug is plastic, special procedures are required to safety-wire the drain plug.
The radiator drain hole extension is plastic, formed-as-one with a plastic tank (bottom of the radiator). The drain plug is wired to a plastic radiator fan support. But the fan support is separate from the radiator, so it moves slightly apart from the radiator. Therefore, if the safety wire is too tight, and does not allow for this slight movement, the movement can break the drain hole extension. The wire will not break from vibration, since it will be vibrating against plastic parts, not metal.
Normally, it is not good practice to wire a plug to an anchor hole on a separate (moving) part. But since all of the parts are plastic anyway, the safety wire cannot be taut, even if the plug and anchor hole are on the same part. So leave the wire slightly loose (curved), so that about 1/8 inch of movement is allowed, before the wire is pulled tight. And do not twist the safety wire too tight, during installation. That would cause too much force on the plastic parts, when wiring the plug.
The anchor hole in the fan support is 1/8 inch versus the normal safety-wire 1/16 inch anchor hole. Use an 18-inch length drill bit to reach and drill this hole. Clean burrs from the edges of the anchor hole, but do not attempt to bevel the edges of the hole. The fan support is plastic, and will not cut the wire.
Instead of the traditional 6-8 twists per inch, I simply used my fingers to loosely twist/ wrap the wire between the plug and anchor hole. All that is required is that the wire cannot loosen/ stretch. It is not required in this case, to hold the drain plug tight, but only to prevent the plug from coming out, should it begin to loosen. Because of the sealing O-ring on the plug tip, the plug would need to twist more than one full turn before it would begin to leak. The drain is actually that small hole in the bottom of the drain-plug extension-tube. Fluid does not drain from around the drain plug itself.
The setup shown in the pictures above has been in my own RDX for the past year.
REMOVING THE RADIATOR DRAIN PLUG:
This can be done from the top-side, by reaching down behind the radiator. If you are safety-wiring the plug, then remove the Splash Guard and do everything from below. You will need to do that anyway for access to safety-wire the plug, and the easier access to the plug will make it easier to remove.
However, I was not strong enough (in my fingers) to remove the plug without using a pair of pliers. Just make certain not to twist to the side or you will break the drain extension-tube.
INSTALLING THE RADIATOR DRAIN PLUG:
When I tightened the plug, I did so from below, with the Splash Guard removed. I just used my hand, without pliers, because I lubed the plug-threads. I wanted to make certain that I did not over-tighten, so I used the paint mark on the plug as a reference.
Put a smear of Synco Super Lube® Synthetic Grease (no silicone) on the rubber O-ring, so that it is not damaged when the plug is installed, or removed the next time. If you are not concerned about contaminating the radiator coolant with silicone, you can also use Silicone Grease – just a tiny smear. The O-ring is tiny, and only the front face of the O-ring touches the water inside the drain extension-tube.
I prefer to use Silicone (dielectric) Grease on the plug threads, which are behind the O-ring seal and are not touched by the water inside the radiator. Super Lube for rubber parts that slide/ move, Silicone Grease for static (unmoving) parts, like the tightened plug threads.
Plastic-against-plastic will oxidize and seize over time from heat, moisture, etc. – plastic plug threads against plastic internal drain-hole threads. The grease will prevent seizing and allow the plug to be removed easily next time. Otherwise you risk breaking the plastic radiator drain extension from excessive force.
----eof
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
If the radiator drain plug falls out, the engine will overheat and probably be permanently damaged. That is unlikely. But I prefer to think in terms of the results of what can happen, rather than the likely-hood that nothing bad will happen. Something bad always happens to somebody – I prefer that it is not me.
NOTE: the drain plug has no washer, like on an oil drain-plug, but instead a tiny sealing O-ring on the plug tip. I would suggest that this O-ring be replaced each time the radiator fluid is flushed, especially if you wait the 5-years between flushes. Rubber does deteriorate from heat and water and chemicals (radiator coolant). When re-installing the drain plug, the O-ring should be lubricated – see below.
NOTE: there is (or was) a factory paint mark on your radiator drain plug. You can use this mark to check that the drain plug is not coming loose, by looking at the mark at every oil change. And if the factory mark is missing, you can add your own mark as in the next picture. You can add you own paint mark through the existing slot in the Front Bumper Cover.
Such a mark will also tell you how tight to install the drain plug after you perform a drain-and-fill of coolant. Since all parts are plastic, it is helpful to know just how tight to replace the drain plug without breaking something, and so that the drain plug does not leak.
NOTE: a transmission aftermarket inline filter has been added in these pictures of the radiator drain plug safety-wiring. That is why the pictures look slightly different from your stock RDX.
Safety wiring the radiator drain plug requires removal of the front Splash Guard, which is located between the front bumper cover, and the front frame cradle, in front of the engine oil pan. For tips on removing the Splash Guard, look at my post for adding a Power Steering inline filter, about half way down the post..
LINK to: DIY – Add a Power Steering Replaceable Inline Magnetic Filter
https://acurazine.com/forums/showthread.php?t=828859
WIRING THE RADIATOR DRAIN PLUG:
Since the radiator is plastic, and the drain plug is plastic, special procedures are required to safety-wire the drain plug.
The radiator drain hole extension is plastic, formed-as-one with a plastic tank (bottom of the radiator). The drain plug is wired to a plastic radiator fan support. But the fan support is separate from the radiator, so it moves slightly apart from the radiator. Therefore, if the safety wire is too tight, and does not allow for this slight movement, the movement can break the drain hole extension. The wire will not break from vibration, since it will be vibrating against plastic parts, not metal.
Normally, it is not good practice to wire a plug to an anchor hole on a separate (moving) part. But since all of the parts are plastic anyway, the safety wire cannot be taut, even if the plug and anchor hole are on the same part. So leave the wire slightly loose (curved), so that about 1/8 inch of movement is allowed, before the wire is pulled tight. And do not twist the safety wire too tight, during installation. That would cause too much force on the plastic parts, when wiring the plug.
The anchor hole in the fan support is 1/8 inch versus the normal safety-wire 1/16 inch anchor hole. Use an 18-inch length drill bit to reach and drill this hole. Clean burrs from the edges of the anchor hole, but do not attempt to bevel the edges of the hole. The fan support is plastic, and will not cut the wire.
Instead of the traditional 6-8 twists per inch, I simply used my fingers to loosely twist/ wrap the wire between the plug and anchor hole. All that is required is that the wire cannot loosen/ stretch. It is not required in this case, to hold the drain plug tight, but only to prevent the plug from coming out, should it begin to loosen. Because of the sealing O-ring on the plug tip, the plug would need to twist more than one full turn before it would begin to leak. The drain is actually that small hole in the bottom of the drain-plug extension-tube. Fluid does not drain from around the drain plug itself.
The setup shown in the pictures above has been in my own RDX for the past year.
REMOVING THE RADIATOR DRAIN PLUG:
This can be done from the top-side, by reaching down behind the radiator. If you are safety-wiring the plug, then remove the Splash Guard and do everything from below. You will need to do that anyway for access to safety-wire the plug, and the easier access to the plug will make it easier to remove.
However, I was not strong enough (in my fingers) to remove the plug without using a pair of pliers. Just make certain not to twist to the side or you will break the drain extension-tube.
INSTALLING THE RADIATOR DRAIN PLUG:
When I tightened the plug, I did so from below, with the Splash Guard removed. I just used my hand, without pliers, because I lubed the plug-threads. I wanted to make certain that I did not over-tighten, so I used the paint mark on the plug as a reference.
Put a smear of Synco Super Lube® Synthetic Grease (no silicone) on the rubber O-ring, so that it is not damaged when the plug is installed, or removed the next time. If you are not concerned about contaminating the radiator coolant with silicone, you can also use Silicone Grease – just a tiny smear. The O-ring is tiny, and only the front face of the O-ring touches the water inside the drain extension-tube.
I prefer to use Silicone (dielectric) Grease on the plug threads, which are behind the O-ring seal and are not touched by the water inside the radiator. Super Lube for rubber parts that slide/ move, Silicone Grease for static (unmoving) parts, like the tightened plug threads.
Plastic-against-plastic will oxidize and seize over time from heat, moisture, etc. – plastic plug threads against plastic internal drain-hole threads. The grease will prevent seizing and allow the plug to be removed easily next time. Otherwise you risk breaking the plastic radiator drain extension from excessive force.
----eof
09-05-2012, 08:48 PM
#6
Burning Brakes
Thread Starter
How to Safety Wire a TRANSFER CASE Drain Plug:
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
Because of the design of the RDX transfer case drain hole, and the high OEM torque value, there is a very real possibility that the aluminum drain hole threads will be stripped during one of the oil changes – very bad.
By replacing both the OEM RDX transfer case drain and fill plugs with an OEM Subaru engine drain plug, the Subaru plugs can easily be drilled and safety wired. I made this change about 1-year ago, at 22K miles.
1) Because I use a lower than OEM torque, I am not worried about stressing the drain hole threads (no matter how many times the oil is drained).
2) And because I safety-wire the drain plug, I am not worried about the drain plug falling out.
PICTURES: transfer case
The dirt on the plugs is because the plugs are coated with silicone (dielectric) grease, and dirt sticks. And the grease is why there is no corrosion on the plugs.
PICTURES: transfer case
The OEM RDX drain plug has a flat head with an indent for a 3/8 (10mm) square drive. Although the hex-head bolt shown in the picture above projects down 3/4-inch below the transfer-case, note that the frame member is about 2-inches below the case. The part of the frame in the picture above is the rear cross member of the front frame cradle. If something hits the drain-plug, it is definitely going to hit the frame-member next, and the car will come to an abrupt stop with significant damage.
PICTURES: transfer case
Yes, as you can see in the picture above, the Oil Filter hangs lower than the transfer case, and the engine Oil Pan is lower than the oil filter. Just take a look under your own RDX from the front bumper.
PICTURES: transfer case
The leftmost anchor hole in the picture above, was where I intended to wire the drain plug, not the fill plug. But the rightmost anchor hole cannot be used for the fill plug, unless the wire is looped OVER the top of the fill plug, instead of AROUND the fill plug head (as shown). Because of the angle, if the wire is looped around the plug head, it will want to flip-up.
And yes, I have wired the plugs both ways. Unless the car is jacked up well off the floor, neither is easy. I guess it just depends upon what seems to work best when I am under the car and wiring the plugs.
When you see how the rear differential plugs are wired (next post), you might think those are the most difficult. But for me, these two transfer-case plugs are the most difficult, of all of the drain plugs that I have wired. Still, while they may take a bit more time than say, the engine drain plug, if the front of the car is on jack-stands, and it is not too cold or hot (and uncomfortable), I manage to get it done.
Exactly where you drill your anchor holes, and how you wire the two plugs, is something for you to decide. The pictures above show what I have done.
WHY ARE THE THREADS in the RDX TRANSFER CASE DRAIN HOLE EASILY STRIPPED?
The drain-hole in the RDX transfer-case is kind of strange. A boss is cast above the drain-hole, inside the case. It looks kind of like a volcano sitting on the inside floor of the transfer-case. The boss is drilled and tapped for the drain-plug. The boss drain-hole is the same 14mm length as the drain-plug, so it has the same number of threads.
To allow oil to drain all the way to the bottom of the case, a slot has been machined into the side of this boss, on the driver-side of the case drain-hole. And there are only about 6-threads because the hole is short. So the drain-hole is short (few-threads), the plug is large (20mm in diameter), and part of the threads into the case drain-hole have been machined away.
I think that the engineer who set the OEM torque at 33 ft-lbs was smoking crack. I am amazed that the aluminum case threads are not stripped – probably only because on the average RDX the transfer case oil is only changed once or twice in 100K miles.
The transfer-case oil is to be changed with the transmission oil. I have no idea how often the MID will ‘normally’ request this, but the Owner’s Manual says under severe driving conditions, to change the oil (transfer and transmission) at 60K miles, and then every 30K miles after that.
Since the transfer-case holds less than 1/2-quart of oil, I think that the only reason for the long oil-change-interval, is because most of the time, most of the engine power is delivered through the front drive-axles. Unless the RDX is driven in a ‘spirited’ manner, either in curves or hills (or snow), little or no power is flowing through the transfer-case to the rear-wheels.
I change the transfer-case oil once per year, about every 8K miles, and use a synthetic 75W90 oil. And since I change the oil more often than the MID says, I use a torque setting of 225 in-lbs (19 ft-lbs), to prevent wear on the case drain-hole threads. And I safety wire both the fill and drain plugs.
RDX OEM TRANSFER CASE FILL and DRAIN BOLT SIZE:
The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole. I torque these bolts to 225 in-lbs or 19 ft-lbs.
TRANSFER CASE DRAIN AND FILL: 20mm x 1.5 x 14mm length – 6.5 threads
WHERE DID I GET THOSE DRAIN-PLUGS in the PICTURES ABOVE?
The transfer-case plugs used in the pictures above, are OEM Subaru engine drain plugs, p/n 807-0200-10. This drain plug fits all Subaru models prior to 2006. DO NOT use the OEM Subaru drain-plug washer. Use the OEM RDX washer.
The following picture is of a CRV rear-diff drain-plug, but the RDX transfer case OEM drain-plug looks the same.
PICTURES: CRV rear-diff drain plug
PICTURES: plug comparison
PICTURES: plug comparison
SUBARU MAGNETIC DRAIN PLUG:
An OEM Subaru magnetic drain plug p/n 32103-KA-000 is available for around $3, price is no typo. This plug is steel, and has a ceramic magnet inset below the tip/ end of the plug. Unfortunately, this plug has only 4.5 threads. The size is 20mm x 1.5 x 10mm length. I did use this plug for a short time, at a torque setting of 15 ft-lbs. DO NOT use a higher torque, to avoid stripping the threads in the transfer-case.
I was not very happy with the Subaru magnet or the plug, as the magnet is shrouded by the top of the drain-hole, because the Subaru plug is only 10mm long vs. the OEM plug length of 14mm. Also, the magnet is a weak ceramic type. I doubt that it would be very effective.
A drain plug with an extended magnet will also fit. You can check magnet-clearance by inserting a thin screw-driver into the drain hole, and moving it around.
Any aftermarket Subaru engine magnetic drain plug will ‘work’, but I have not found one that I like, so I am currently using the standard Subaru engine drain plug (non-magnetic).
PICTURE: Subaru magnetic drain plug
PICTURE: Subaru magnetic drain plug
HOW TO DRILL AN OEM RDX TRANSFER CASE DRAIN PLUG:
It is possible to drill an OEM RDX transfer-case plug for safety wire, but it is much more difficult than the hex-head Subaru plugs in the pictures above.
There are two basic methods. In the first, hold the drain plug firmly with your left hand, wearing a glove (of course). Then have-a-go with a Dremel tool and 1/16-inch drill bit, as in the next picture.
PICTURE: motorcycle internal-hex bolt
The second method was used in the next picture. First center-punch the starting location. Then drill a shallow VERTICAL start-hole with a 3/32-inch bit. Then use a drill press with a 1/16-inch bit to drill the wire-hole. For support, hold the plug at an angle firmly against a non-compressible foam pad, such as used for appliance packaging.
Start the 1/16-inch hole at about 20 degrees from vertical. You are drilling against the bottom angle of the larger shallow VERTICAL hole. Then, as the bit begins to drill, slowly rotate the plug so that the drill-bit angle approaches 45 degrees from vertical. That is how the following plug was drilled.
PICTURE: RDX drain plug
PICTURE: RDX drain plug
I did not stop when the drill-bit broke through the inside of the plug, and accidentally drilled into the bottom of the square hole. That does not really hurt anything on a drain plug, as the plug is not a stressed part, holding something together.
PICTURE: RDX drain plug
Both ends of the wire-hole have been chamfered with a larger drill bit, by hand. That is to prevent the safety-wire from being cut by a sharp edge of the holes. And that is why the top hole looks so much larger than 3/32-inch. A 1/8 inch bit was used to chamfer the top hole. DO NOT use a larger bit than 3/32 inch to drill the start-hole. Otherwise, the 1/16-inch wire-hole bit will wander too much when trying to start the angled-hole.
PICTURE: RDX drain plug
----eof
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
Because of the design of the RDX transfer case drain hole, and the high OEM torque value, there is a very real possibility that the aluminum drain hole threads will be stripped during one of the oil changes – very bad.
By replacing both the OEM RDX transfer case drain and fill plugs with an OEM Subaru engine drain plug, the Subaru plugs can easily be drilled and safety wired. I made this change about 1-year ago, at 22K miles.
1) Because I use a lower than OEM torque, I am not worried about stressing the drain hole threads (no matter how many times the oil is drained).
2) And because I safety-wire the drain plug, I am not worried about the drain plug falling out.
PICTURES: transfer case
The dirt on the plugs is because the plugs are coated with silicone (dielectric) grease, and dirt sticks. And the grease is why there is no corrosion on the plugs.
PICTURES: transfer case
The OEM RDX drain plug has a flat head with an indent for a 3/8 (10mm) square drive. Although the hex-head bolt shown in the picture above projects down 3/4-inch below the transfer-case, note that the frame member is about 2-inches below the case. The part of the frame in the picture above is the rear cross member of the front frame cradle. If something hits the drain-plug, it is definitely going to hit the frame-member next, and the car will come to an abrupt stop with significant damage.
PICTURES: transfer case
Yes, as you can see in the picture above, the Oil Filter hangs lower than the transfer case, and the engine Oil Pan is lower than the oil filter. Just take a look under your own RDX from the front bumper.
PICTURES: transfer case
The leftmost anchor hole in the picture above, was where I intended to wire the drain plug, not the fill plug. But the rightmost anchor hole cannot be used for the fill plug, unless the wire is looped OVER the top of the fill plug, instead of AROUND the fill plug head (as shown). Because of the angle, if the wire is looped around the plug head, it will want to flip-up.
And yes, I have wired the plugs both ways. Unless the car is jacked up well off the floor, neither is easy. I guess it just depends upon what seems to work best when I am under the car and wiring the plugs.
When you see how the rear differential plugs are wired (next post), you might think those are the most difficult. But for me, these two transfer-case plugs are the most difficult, of all of the drain plugs that I have wired. Still, while they may take a bit more time than say, the engine drain plug, if the front of the car is on jack-stands, and it is not too cold or hot (and uncomfortable), I manage to get it done.
Exactly where you drill your anchor holes, and how you wire the two plugs, is something for you to decide. The pictures above show what I have done.
WHY ARE THE THREADS in the RDX TRANSFER CASE DRAIN HOLE EASILY STRIPPED?
The drain-hole in the RDX transfer-case is kind of strange. A boss is cast above the drain-hole, inside the case. It looks kind of like a volcano sitting on the inside floor of the transfer-case. The boss is drilled and tapped for the drain-plug. The boss drain-hole is the same 14mm length as the drain-plug, so it has the same number of threads.
To allow oil to drain all the way to the bottom of the case, a slot has been machined into the side of this boss, on the driver-side of the case drain-hole. And there are only about 6-threads because the hole is short. So the drain-hole is short (few-threads), the plug is large (20mm in diameter), and part of the threads into the case drain-hole have been machined away.
I think that the engineer who set the OEM torque at 33 ft-lbs was smoking crack. I am amazed that the aluminum case threads are not stripped – probably only because on the average RDX the transfer case oil is only changed once or twice in 100K miles.
The transfer-case oil is to be changed with the transmission oil. I have no idea how often the MID will ‘normally’ request this, but the Owner’s Manual says under severe driving conditions, to change the oil (transfer and transmission) at 60K miles, and then every 30K miles after that.
Since the transfer-case holds less than 1/2-quart of oil, I think that the only reason for the long oil-change-interval, is because most of the time, most of the engine power is delivered through the front drive-axles. Unless the RDX is driven in a ‘spirited’ manner, either in curves or hills (or snow), little or no power is flowing through the transfer-case to the rear-wheels.
I change the transfer-case oil once per year, about every 8K miles, and use a synthetic 75W90 oil. And since I change the oil more often than the MID says, I use a torque setting of 225 in-lbs (19 ft-lbs), to prevent wear on the case drain-hole threads. And I safety wire both the fill and drain plugs.
RDX OEM TRANSFER CASE FILL and DRAIN BOLT SIZE:
The thread count considers only fully formed threads. And disregards whether or not the bolt thread can engage the internal threads inside the drain hole. I torque these bolts to 225 in-lbs or 19 ft-lbs.
TRANSFER CASE DRAIN AND FILL: 20mm x 1.5 x 14mm length – 6.5 threads
WHERE DID I GET THOSE DRAIN-PLUGS in the PICTURES ABOVE?
The transfer-case plugs used in the pictures above, are OEM Subaru engine drain plugs, p/n 807-0200-10. This drain plug fits all Subaru models prior to 2006. DO NOT use the OEM Subaru drain-plug washer. Use the OEM RDX washer.
The following picture is of a CRV rear-diff drain-plug, but the RDX transfer case OEM drain-plug looks the same.
PICTURES: CRV rear-diff drain plug
PICTURES: plug comparison
PICTURES: plug comparison
SUBARU MAGNETIC DRAIN PLUG:
An OEM Subaru magnetic drain plug p/n 32103-KA-000 is available for around $3, price is no typo. This plug is steel, and has a ceramic magnet inset below the tip/ end of the plug. Unfortunately, this plug has only 4.5 threads. The size is 20mm x 1.5 x 10mm length. I did use this plug for a short time, at a torque setting of 15 ft-lbs. DO NOT use a higher torque, to avoid stripping the threads in the transfer-case.
I was not very happy with the Subaru magnet or the plug, as the magnet is shrouded by the top of the drain-hole, because the Subaru plug is only 10mm long vs. the OEM plug length of 14mm. Also, the magnet is a weak ceramic type. I doubt that it would be very effective.
A drain plug with an extended magnet will also fit. You can check magnet-clearance by inserting a thin screw-driver into the drain hole, and moving it around.
Any aftermarket Subaru engine magnetic drain plug will ‘work’, but I have not found one that I like, so I am currently using the standard Subaru engine drain plug (non-magnetic).
PICTURE: Subaru magnetic drain plug
PICTURE: Subaru magnetic drain plug
HOW TO DRILL AN OEM RDX TRANSFER CASE DRAIN PLUG:
It is possible to drill an OEM RDX transfer-case plug for safety wire, but it is much more difficult than the hex-head Subaru plugs in the pictures above.
There are two basic methods. In the first, hold the drain plug firmly with your left hand, wearing a glove (of course). Then have-a-go with a Dremel tool and 1/16-inch drill bit, as in the next picture.
PICTURE: motorcycle internal-hex bolt
The second method was used in the next picture. First center-punch the starting location. Then drill a shallow VERTICAL start-hole with a 3/32-inch bit. Then use a drill press with a 1/16-inch bit to drill the wire-hole. For support, hold the plug at an angle firmly against a non-compressible foam pad, such as used for appliance packaging.
Start the 1/16-inch hole at about 20 degrees from vertical. You are drilling against the bottom angle of the larger shallow VERTICAL hole. Then, as the bit begins to drill, slowly rotate the plug so that the drill-bit angle approaches 45 degrees from vertical. That is how the following plug was drilled.
PICTURE: RDX drain plug
PICTURE: RDX drain plug
I did not stop when the drill-bit broke through the inside of the plug, and accidentally drilled into the bottom of the square hole. That does not really hurt anything on a drain plug, as the plug is not a stressed part, holding something together.
PICTURE: RDX drain plug
Both ends of the wire-hole have been chamfered with a larger drill bit, by hand. That is to prevent the safety-wire from being cut by a sharp edge of the holes. And that is why the top hole looks so much larger than 3/32-inch. A 1/8 inch bit was used to chamfer the top hole. DO NOT use a larger bit than 3/32 inch to drill the start-hole. Otherwise, the 1/16-inch wire-hole bit will wander too much when trying to start the angled-hole.
PICTURE: RDX drain plug
----eof
09-21-2012, 10:39 PM
#7
Burning Brakes
Thread Starter
UPDATE – How to Safety Wire a TRANSFER CASE Drain Plug
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
MINOR CORRECTION: in my previous post, I mistakenly stated that the Engine Oil Filter hangs lower than the Transfer Case.
Actually, the Front Frame Cradle is the lowest part under the front of the vehicle. The Engine Oil Pan & Filter and the Transfer Case are higher. In other words, the Frame protects the drive-train parts. Here are a couple of pictures showing the relative location of the parts.
Of course you can just look under your own vehicle. But I have sometimes been confused by pictures posted (by others) as close-up details, as to the actual relationship between various parts. So perhaps these pictures will make the location of the various parts discussed in this thread, a bit more clear.
Anyway, the main point is that although the Transfer-Case replacement (non-OEM) HEX-head drain plug may project slightly below the bottom of the transfer case, the Plug is still well above the bottom of the Frame.
PICTURES: under the RDX front looking toward the rear
PICTURES: transfer case Drain Plug location
----eof
DANGER: use safety Jack-Stands if you jack up your car, and take other safety measures when working on your car. Wear eye protection when safety wiring – you can blind yourself with the wire ends, by carelessness.
MINOR CORRECTION: in my previous post, I mistakenly stated that the Engine Oil Filter hangs lower than the Transfer Case.
Actually, the Front Frame Cradle is the lowest part under the front of the vehicle. The Engine Oil Pan & Filter and the Transfer Case are higher. In other words, the Frame protects the drive-train parts. Here are a couple of pictures showing the relative location of the parts.
Of course you can just look under your own vehicle. But I have sometimes been confused by pictures posted (by others) as close-up details, as to the actual relationship between various parts. So perhaps these pictures will make the location of the various parts discussed in this thread, a bit more clear.
Anyway, the main point is that although the Transfer-Case replacement (non-OEM) HEX-head drain plug may project slightly below the bottom of the transfer case, the Plug is still well above the bottom of the Frame.
PICTURES: under the RDX front looking toward the rear
PICTURES: transfer case Drain Plug location
----eof
Trending Topics
07-12-2013, 01:23 PM
#8
In all my 50 years I have yet to lose an oil drain plug, radiator drain plug, oil filter or any other "sealing" plug on my cars. While there may be some merit to your method but to me it seems like a great big waste of time. And trust me when I say this, I love cars and am a certified gear head but I think that a better use of your resources should be spent on making sure your hoses, particularly your transmission lines, brake lines etc are all in good working condition. Just saying...
07-13-2013, 03:48 AM
#9
Burning Brakes
Thread Starter
Every racing organization *requires* safety wiring, for a very good reason - so I assume you have never engaged in racing (for real) in your 50 years of ???? - I have. Or perhaps you have never had a drain plug stripped, or left loose by a careless *mechanic* at the local quicky-lube or even by the car dealer - I unfortunately have suffered that fate. I do my own oil changes now, and safety wire (belt and suspenders).
And probably you have never driven 17 miles (one way) down a rutted dirt road on the Navaho reservation, just to look at some rocks, in your RDX. But my wife & sister think this is great fun - and guess what would happen if some drain plug should happen to fall out?
Yes, I do that too.
Certified?
Certified?
07-13-2013, 04:41 AM
#10
Burning Brakes
Thread Starter
Perhaps you have never had a stripped drain plug hole in an aluminum pan? or perhaps you do not keep your vehicle for 20 years, or else you are very careful about torquing the drain plugs - regardless, eventually the threads will wear.
07-13-2013, 05:31 AM
#11
10-31-2013, 04:17 PM
#12
Chapter Leader (Southern Region)
the sig brought me here.. marco 
Thread
Thread Starter
Forum
Replies
Last Post
mlody
5G TLX (2015-2020)
85
12-04-2019 02:11 PM
SUPRMN84
3G TL Audio, Bluetooth, Electronics & Navigation
5
10-07-2015 09:46 PM
xsilverhawkx
2G TL Problems & Fixes
5
09-28-2015 06:51 PM
STL TL-S
3G TL Problems & Fixes
9
09-23-2015 08:52 PM
