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Crush Washers for Trans Oil Change


Rob F.

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I'm going to change my transmission oilon my R1200RT but as BMW notes, the washers on both the filler and drain plug need replacing. The parts microfiche doesn't list any. Only the drain plug has a part # which includes the washer. The filler plug doesn't even show the washer. Any ideas how to get these by themselves? I've been told these are "lifetime" washers to be used over and over (yeah, right) and that why they are sold separately.

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I personally believe the need to replace crush washers "every time" you change fluid is highly "over-rated". Clean it off and put it back and everything will be fine.

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When I changed trans oil on my R12S was in the same situation. On the S, even though the fiche shows a crush washer, there isn't one. An o-ring is integral to the plug. I replaced the plug with a new one.

 

BMW cars have made the same transition to no crush washers and using integral O-rings instead.

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I personally believe the need to replace crush washers "every time" you change fluid is highly "over-rated". Clean it off and put it back and everything will be fine.

Exactly. That is why they are called "crush washers"... they crush to make a seal. In the past 5 years, that included 2 to 3 changes of engine oil a year, and one or 2 changes of tranny and rear end oil a year, I only replaced ONE crush washer (and that was only because it got too thin). The bike has NEVER leaked a drop. Ever.

 

Seems to me that this should answer the question "is it really nceessary to replace the washers every time." The answer is "of course not!".

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finallyabeemer

Engineer steps in:

When aluminum or copper washer are crushed, they work harden just a little. The more they are crushed, the more they harden. And the risk of weeping or leaking is slightly higher with a hardened washer. Leaks, if severe enough and ignored enough, could end up contributing to a oil slicked tire and a crash. Which gets the liability attorneys just a little worked up.

So, we recommend they be changed every time to minimize risk.

But with proper care (no over torquing, please!) and a quick inspection to verify proper sealing, they can be re-used a couple/few times. I do.

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I just go to my local BMW dealer and ask the parts guy for the crush washers for the transmission and final drive drains. He give me a couple and charges me a couple of bucks. If your dealer doesn't do this, maybe you need to look for another dealer. Sorry...maybe you don't have that option but sometimes it just that simple.

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Don_Eilenberger
The questions is that I can't seem to be able to buy the washer by themselves.
Harbor Freight has a kit of 100 or so in lots of different sizes - $3.99. Can't beat it for junk like this.. (and their mini-ratchets are about my favorites - 6" long padded handles, nice fine ratchet, about $2/each on sale..)
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The questions is that I can't seem to be able to buy the washer by themselves.
Harbor Freight has a kit of 100 or so in lots of different sizes - $3.99. Can't beat it for junk like this.. (and their mini-ratchets are about my favorites - 6" long padded handles, nice fine ratchet, about $2/each on sale..)

 

+1

 

I find that the "new" replacement plugs are a waste. I simply cut the old crush washer off and install a new one.

 

Jim cool.gif

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Engineer steps in:

When aluminum or copper washer are crushed, they work harden just a little. The more they are crushed, the more they harden.

Another engineer steps in. Aluminum does not work harden... at least not the intentionally soft alloy used for crush washers. Copper does, but for galvanic corrosion reasons, copper washers are generally not used against aluminum housings.

 

With an aluminum washer, you can easlily retorque it until it is paper thin.

 

But theory is irrelivant. The fact is (as I and many others will attest) that you will get a perfect seal every time even if you reuse an aluminum washer (until, of course, it gets gets extruded out and so thin as to be useless).

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Don_Eilenberger
+1

 

I find that the "new" replacement plugs are a waste. I simply cut the old crush washer off and install a new one.

 

Jim cool.gif

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=93324 - that's the copper ones (preferred by some people since they can be softened and used again..) If you get on their email special list - you'll get a coupon for them once in a while for $3.99 or so..

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aggieengineer

"Another engineer steps in. Aluminum does not work harden... at least not the intentionally soft alloy used for crush washers. Copper does, but for galvanic corrosion reasons, copper washers are generally not used against aluminum housings."

 

I certainly reuse aluminum and copper washers, but I was unaware that there was any aluminum alloy, even 1100 series metals, that were immune to work hardening.

 

Must be time to blow the dust off those old engineering textbooks from the previous century!

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Don_Eilenberger
And what's the torque conversion value for substituting copper for aluminum? grin.gif
I've never bothered torquing crush washer applications. When the washer starts to crush - it's tight enough.. (or if it starts turning real easy - whichever comes first.. crazy.gif )
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