New Leak

[r65lsk75c]

I finally found a few minutes to move the R65LS around the garage this afternoon. It would appear I discovered another issue for my restoration program. A very visible lubricant leak was observed and appeared to be coming from the right side of the rear drive. Lubricant was running onto the tire and was obviously not coming from the drain plug.

Could this be an explanation for the rear brake appearing to be rather useless at the end of the riding season?

Where do I start with the trouble-shooting process? I assume that the culprit is likely a seal. Is this something that I have a chance to repair?

Rick T.

[Polarbear]

Check the ventilation to rear drive. It is on top of housing and needs to be breathing. If not breathing, things like leaks come quickly. The rearends do come apart fairly simply, with few tools. There is a seal just inside the drive splines on the ring gear that goes bad every 15-20 years. Not really very often, huh. Once in a while, one will fail on newer bikes, but I've seen few. My GS1100 was one! My R100/7, this seal has never failed in 28 years. Another seal separates the drive shaft oil from rear oil and if the drive shaft oil has crept into the rear unit, it will overfill the rear unit causing leakage. This one is harder to get to and requires the pinion to come out. This one is also a long lived seal. I would guess the breather is a good(simple) place to start and move from there. Then ring gear seal is easy to replace, by removing the bolts around the splines cover. Watch out for shims and be sure they go back as removed. Buy the new gaskets before taking it all apart. Your local beemer shop should have them or order them. You can check for overfill when removing the fill plug; if oil runs out freely when the plug comes out, you're in an overfill condition and oil from drive shaft housing is creeping in from that pinion seal I mentioned. Before I took it all apart, however, I'd change the oil and try again to see if in fact it overfills again with time. May well cure itself. The seals love WD40, if in fact you drain all the oil and clean the inner parts, seals with WD40! Large amounts of WD40...Good stuff! This sometimes gives seals a second life, just cleaning the system. Sure does not hurt anything to try some simple remedies from old school wrenches. Happy Trails, Good luck Randy13233

[RandyB]

Check the little bolt that holds the ground wire to the transmission. There's a hole through the center that needs to be open to allow pressure in the transmission to vent.

[donbmw]

How often has the rear wheel been off. If the spline on the wheel have had to much gears this could be the problem. Remove wheel and clean everything check levels in rear end and shaft. Go ride and check wheel again.

Don