Bevel Drive Pivot Bearing Failure
 

Whilst servicing my 1989 R100GS two days ago I discovered some free play in the back wheel. Upon closer inspection I found that the tapered roller bearing on the bevel drive pivot stub (left hand) had failed and was about to disintegrate.
Does anybody have any idea what may have caused this other than component failure (the bike's only done 35000 miles)?
I'd like to avoid a repeat of this as finding BMW parts in Southern India is proving somewhat tricky and I hate to think what might have happened if it had failed whilst fully loaded trundling along a Goan road...
Harvey
www.chasingthesun.org

hi harvey
those bearing can go as early as 35,000miles keep a close eye on the front uj on the shaft as they are can go as well nobby

Having spent three memorable hours back in the UK trying to help Harvey refit the bevel housing back onto the drive shaft - and looking forward to the repeat experience when we finally manage to get hold of the bearings - I was wondering how you can check up on things like that without removing the bevel housing each time (a complete pain in the preverbial)? It was the outer casing of the bearing that failed which you cannot see without taking it all apart. Also any tips on keeping an eye on the front universal joint - is it as difficult to see into as the rear one?
Cheers
Lisa www.chasingthesun.org

Checking the housing bearing isn't possible without taking it apart, other than checking for looseness in the wheel.

It's not a very common problem, but it does happen. On the non-paralever model it's extremely rare.

Checking the u-joint on the front is a hassle, not worth getting in there to do. Just spin the wheel slowly and listen/feel for roughness - in both directions. You can squeeze the rubber boot at the front and feel the shaft rotating. The rotating bumps are the u-joint. If it starts getting lumpy/rough there is a problem coming. Get a spare driveshaft and carry it from then on, or replace if you are heading off into the boonies. It can fail suddenly. Consider the paralever driveshaft a standard maintenance replacement item - 30-60,000 miles.

The non-paralever driveshaft will probably never fail.

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Grant Johnson

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at: www.HorizonsUnlimited.com