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crushing the crush washer


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are there torque specs for either the rear drive, the gear box or the oil drain plugs? or does the crush washer on these plugs act as a torque spec on its own? what i want to ask is if i replace the crush washer each time with a fresh one, then tighten it until its firm, and then feel that little extra smoosh when the washer flattens some, isnt that the perfect torque or tightness for any of these particular plug fittings? smooshing the crush washer would not ever, if only tightened until i feel that feel, cause the plug to be over tight would it?


and outside of an aftermarket manual, are there general torque specs for the R1100S handy somewhere i could be directed to?


much obliged..P.

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The 'crush washers' on BMWs are simple aluminium or copper washers and do not crush as such, they just deform slightly at the contact face to form a seal. Use the specified torque and if you find that you are short of a crush washer just re0use the old one.



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...smooshing the crush washer...


I like your description, "smooshing" the crush washer.


I'll have remember that.


Pay attention to what the previous responders said.


They know of what they speak. thumbsup.gif

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You can anneal the crush washer, the process you described. It is a method of removing the work hardening that occurs when the metal is stretched or compressed. Kind of overkill in this situation though. It does require some pretty high temperatures. The washers are likely stamped out of sheet stock of some malleable alloy like 3003. Here is the rub, the annealing temperature is around 800 degrees C. Melting point is around 1200 degrees C. Given the tiny mass and likely oversize heat source (welding torch), you will probably overheat the metal and ruin the crushing capability of the washer. An old trick is to use a yellow flame to coat one side of the washer with carbon and then heat the other side, using a now neutral flame, until the carbon just burns off.

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What a great oppertunity to get on the ground floor of a small garage bussiness. Having everyone send you their used crush washers to renew, than outsourse it to Afganistan. grin.giflmao.gif

Except for the fit and finish, they would be as good as new. tongue.gif

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The owner got his money out of this one, never had been replaced in 8 years and a dozen oil changes. It's worth noting that it was not leaking when I removed it!



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I used to do this with the solid copper head gaskets on my turbo and nitrous bikes. They involved a quench in water as well. Heat to dull red heat and then drop in a tub of water. On a head gasket it makes sense. On a crush washer not so much.


For the record, I have never replaced or done anything other than a wipe and a squint to make sure it wasn't scratched to any crush washer on any of the bikes I have owned over the last 50 or so years. Never had a leak either.


There are washers available that have a captured O-ring built into them for the truly paranoid. McMaster Carr has them under the category "sealing washers".


The one place I don't, if I can help it, reuse crush washers is on banjo bolts in the brake system. I have done so when stuck but always secure and install a replacement set as soon as possible.

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Kinda off topic,but you mentioned O Rings.

Can't remember the size used for a friction "cruise control" on the grip of an RT-which I have a nice Caterpillar yellow one in my glovebox-

Well,I had a leaky fuel line on the the 300D coming out of the tank.When I unscrewed the line,the leak was caused by a improperly seated O ring on the fuel strainer.You guessed it they are the same size!!!

Finished the job in half an hour-luckiest I've ever gotten outside of a car!

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