The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: invincibleone on July 22, 2009, 03:28:08 PM
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Hello all-
I just (yesterday) purchased a 1982 R65LS with just 14k miles. The bike was serviced two weeks & just 13 miles ago (according to the receipt) prior to the purchase. But it seems like oil is leaking out of the rear diff onto my brakes & out of the drum onto my wheel & tire. Could this be caused by simply overfilling the rear diff or is there likely a bigger issue?
Any help is much appreciated-
Fissel
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Could be the large O-ring seal in the final drive housing. Fresh lube probably rinsed away all the grit that was keep the 90wt inside. ;) Got dino or synthetic?
Monte
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I believe it is dino oil, but the paperwork doesn't say. Also, I checked the level & it was definitely overfilled. I let about 150+cc of oil trickle out of the fill plug.
Is the o-ring difficult to change? I will be removing the rear wheel to change the (assumingly) oil saturated rear shoes in the next few days anyway.
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Could be four possibilities for leakage, one is the rear brake cam, it has 2 or 3 o-rings on it .
The output shaft seal .
Paper gasket on final drive cover .
Loose bolts that hold the cover to the final drive housing .
Need to remove the rear wheel, clean up the area, and wait to see what starts leaking .
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I posted a response in your other thread with some additional items to check on possible causes of final drive leaks.
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Could be the large O-ring seal...
Correcting myself here. It's an actual oil seal rather than an O-ring. Not overly difficult to replace. Just a bit fiddly as some of our Brit bros say.
Monte
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A very common cause for gear lube leaking onto the brakes and generally making a mess of things is the O-rings on the brake actuating cam where it's shaft goes through the final drive. As old as the bike is these are probably hard as a rock...
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Several possibilities of gear oil leak from inside the final drive/rear wheel hub:
1. There are 6-8 "cover bolts" that hold the inside cover of the final drive on (these are inside the rear wheel hub and around the perimeter of the final drive under the rear brake shoes. I once had one of these come a bit loose and seep oil. simple cleanup and retighten fixed it.
2. The rear brake actuating rod that goes through the final drive to actuate the rear brake shoes has 1, 2 or 3 O ring seals on it. These can sometimes deteriorate/leak. I have also discovered that if the shaft has some "play" in it such that you can push it in/out with the rear wheel off and rear brake shoes removed, it might be moving such that the o-rings aren't staying in proper place to seal. Making sure that the CAM and washer on the inside are flush to the inside cover of the final drive, and putting the splined lever fully seated on the outside part of the rod prevents the side-to-side play and stopped a leak on my bike.
3. The large seal which goes around the drive splines that engage the splines on the wheel hub can sometimes fail/leak, but this isn't very common.
4. The "cap" on the very top of the final drive housing must be able to "breathe", or else under running conditions when the oil, etc. heats up it can become pressurized, and try to force oil out any weak points (Seals) in the system which otherwise wouldn't leak. It may be clogged.
5. It could have been overfilled, combined with #4, or not.
6. Either the drain plug (bottom of final drive) or "check" plug (horizontal/back edge of final drive) is loose, or bolt hole stripped, or crush washer needs replacing.
Most of the above items aren't very serious and easily fixed, but if you get oil on the brake shoes you'll likely contaminate them and have to replace them. Recommend you clean it all up, check careful, take for a little spin and then recheck for where it appears to be coming out of - we can help you from there.
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Hello all-
Thanks for the help. Turns out I was off target slightly. The leak was spline oil coming out of the differential-to-swingarm seal trickling down to the bottom of my diff & spraying all over my wheel. A quick trip to Bobs BMW & a $2.09 gasket fixed everything. I drained & refilled both the diff & splines with 80/90 Bel-Ray Dino oil.
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Never would have thought of that, I don't think I've ever had one of those leak before... :-?