Drive shaft leak

[dadicool59]

Got quite a spirited 430klm ride in on the S yesterday and just discovered oil leaking from the rear rubber drive shaft boot (bellows) at the FD end.
I recently changed gearbox and FD oil to a synthetic which was much thinner than the regular gear oil.
Maybe this has found a weak spot or maybe a coincidence.
So maybe a front drive seal on the FD or a rear gearbox seal maybe both?
Anyone with experience on these? Worth attempting myself? Any specialist tools needed? Cost for dealer to do?
Any advise will be much appreciated.
Cheers in advance

[LeftCoast Peter]

R1?00s ??

[dadicool59]

Sorry, R1100S

[twodear]

Breaking it down isn't too hard - must be careful to mark alignment of the spines on BOTH ends of the shaft to the U-joints at either end.

Assembly is fiddly & frustrating and best done with three or four hands. Tool cost isn't so great but whatever the dealer charges, I'd recommend that.

Pivot points at both ends of the swingarm casting should be inspected and probably replaced. These will also require alignment and preload adjustments during assembly.

[bikerfish1100]

i went thru this very thing last summer. redid FD seal 2x, before finally admitting that it was the rear trans output seal. my confusion was due to seeing no tracing of trans fluid on inside of shaft housing/swingarm. getting that rear seal out was a bit of a bear. you need to thread a screw or similar into the seal body, and then extract with something like a slide hammer. need a heat gun for the pivot bearings. i had someone else do the FD seal, as a jig is needed to hold the FD in place- the nut on there is held on with something like 150 lb ft. if its just the FD seal, i'd pull the FD, and let a shop do the seal replacement. your call on whether you can handle the trans seal yourself. you're looking at several hunnie, just in labor time alone. seals are not all that expensive, but i'd bet shop charge totals to nearly $400.

[Guest24]

If you go to all that trouble, consider a complete bearing and seal job. At least get the shop to give you the estimate. If your bike is a keeper it's worth the thought. Daytona BMW did the complete bearing and seal job last July for $474.00 and they did the FD remove and replace. I've got 98k on the clock.

[bikerfish1100]

i'd agree or disagree with that recommendation Bubba, based solely on 1 question- "what's the bike's mileage?" If under ~40K, don't think i'd bother at all. 40-100K, i'd do the seal, probably check condition of crown bearing (possible with seal in place?). over 100K, i'd take a close look again at the bearing, and then start considering when play shows up. its easy enough to check for shaft play with the FD in your hands. for wahtever reason, the FD bearings on the 11Ss do not seem to have the same suspect track record as on GSs, LTs or RTs of similar vintage. have you observed different than that?

[Guest24]

The bearing was going on mine. I added some stuff, Joe.

[bikerfish1100]

bubba, were you able to feel play in the half-shaft, or was there some other diagnosis? i had 82K on mine when i had the seal replaced (Ted Porter's Beemer Shop), & evidenced no play at all.

[Guest24]

Discovered by tech during seal replacement. Bearing fragments in oil.

[twodear]

There was a recall issued to my 2003 R1150GSA to check the final drive rear wheel play. For sure, mine had play.
1) They replaced the bearing as it was faulty. However, (in my opinion) the shop messed up in disassembly or reassembly as the outer bearing race came loose from the housing within the next month requiring a second attempt.
2) This time the shop replaced the housing and installed all the original bits. This time, within three months the gear teeth on the big gear all broke off - they must have left some nasty thing in there.
3) The end result is that the shop eventually replaced the final drive with one assembled in Germany, and that one is working just fine. By this time the bike was out of warranty but as the original work started before it expired, it was at no cost to me.

[dadicool59]

She is a 2002 and only done 34,000klms or 20,000 miles.

[twodear]

that isn't too many Km for that year so I'd say the bare minimum work and just replace a seal. I believe in that old adage - if it isn't broke...

[Guest24]

I'll have to agree. Just make sure you determine the correct seal to replace.

[RBMann]

Here is a link for the seal replacement at ADV.-

How to fix Leaking input seal on the rear bevel drive - ADVrider

Here are photos of the setup I used to break the nut lose and replace the seal.-

Driveshaft and more love.

Good luck.

[dadicool59]

Thanks for the advise guys.
I have decided to clean her up and change back to some 80W90 dino oil.
I purchased some MOTUL GEARBOX with Moly today.
Apparently the surface tension characteristics of dino is very different to Syn and if she holds I'm happy, if not, based on what Ive read she will be going into the shop as I just don't have the gear that is needed to tackle it.
Thanks to everyone who offered advise.

[Guest24]

Let us know how it goes, mate. Don't see how the dino will make a difference; but, for your wallet's sake i hope it does.