Bevel Box Leak- 1150


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May 28, 2002
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Welwyn Garden City
I've just noticed a leak from the rear bevel box at the point where it connects to driveshaft tunnel. This happened 13 months ago too. It was fixed under warranty at that time. Has anyone else had the same problem? Would it be worthwhile contacting BMW GB? Is it a difficult job to do myself, any pitfalls?

Thanks in anticipation,

Is it definitely a leak (ie dripping oil on floor) or just a 'misting' of an oily film around the boot area. The latter usually in hotter weather/extended use.
I've had this problem on my 1100GS/RT previously and I think on my last 1150GS - can't remember , but I think it's a common problem.
I'm getting a mist forming on the bottom of the drive shaft tunnel, and some oil is also making its way on to the wheel rim. I haven't noticed any drips on the floor where the bike is normally parked.


How wierd! I noticed the same problem on my 1150GS on Friday. Definitely not a drip-drip sort of leak, just a mist of oil outside the gaiter (on the bottom) that connects the drive shaft to the hub.

SLM did a major service to the bike before our trip to Eastern Europe in August, so I called them. Les Walker (Service Manager) reckoned that it was safe to ride as long as the oil level was checked regularily until I could get it in for the seal to be replaced. Their normal experience was it is normally a slow leak caused by excess pressure in the hub, That in turn is often caused by overfilling. I checked the oil level. Guess what, Filled to the top of the thread that takes the filler plug. Les told me it should only come up to the bottom of the thread. So, overfilled - but it was one of Les's people that overfilled it...

I've taken some oil out, but it's still misting, so it's going back for replacement by SLM. I'm expecting them to make a suitable gesture. We'll see, and I'll let everyone know.

Cheers, Norman
Hi Norman,

I had noticed this before I serviced the bike a couple of weeks ago. I measured the exact amount of oil before pouring it in. It might be worth a check to see if the oil that was left inside the drive might contribute to a slight over capacity.

Thanks for that info.

After going to SLM for repair

My bike went into SLM yesterday and they replaced the seal. As explained to me, the job was not trivial, involving removing the hub from the bike so some parts could be heated to break loctite seals. It took 31 units of labour (whatever that means) and £7 in parts.

Sorry Bob, but I forgot to ask your "old oil might still be hanging around to cause the overfill" question.

Initially, Les presented me with the complete bill. After I expressed my unhappiness that a likely cause was the overfilling by one of his mechanics, he offered to split the labour charge 50/50. I'm happy with that. After all, I rode for over 3,000 miles after the service that overfilled the hub, so no-one can be certain that was the cause.

The loaner for the day was a new R850R. Dull isn't the word!


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