First Final Drive Problem

[blaisew]

I think the final drive on my 1150RT had decided to act up here right before Johnson City. I noticed that the area right at the front of the final drive boot was fairly well covered with oil, and that the oil level was almost a quarter inch below the fill level. This is my second RT and I've never had a leak there, but I do now. No play in the rear wheel, but there is some oil staining on around the seal toward the front and to the bottom when viewed with the rear wheel off. The inside of the trailing link boss is also black, so it's a definite leak. Two mechanics inform me that it could be as simple as a failed seal, either on the pinion or on the final drive itself. Perhaps I've caught it early, and I hope so. Next weekend I'll be dropping it off at Alamo BMW near San Antonio for the fix. I guess I'm just grousing a bit, but I'd rather get it fixed now rather than wait for a failure on the road this summer. I'm retiring in three weeks and plan to run the pixx out of if the rest of the year. I'm wondering if I should go ahead and have the bearing replaced while they are at it, but so far the word is not to worry about that if there is no play in the bearing and no trash in the final drive oil.

[smiller]

It sounds like this may be nothing more than pinion seal seepage that has been going on for a while. This is very common, so much so that many don't bother having them replaced as they tend to start leaking again in short order. I would clean it all up and check again in several thousand miles and if there's nothing but a few teaspoons of oil in the boot then an expensive repair is optional. If the leak appears to be coming from the crown bearing/FD output seal however then that is a different case and may be more serious.

 

Also the fact that your FD oil fill was slightly low doesn't really prove much all by itself and another possibility is a leaky transmisison output shaft seal, which can create the same symptoms. You can usually tell what's going on by shining a light up the swingarm housing, if you see oil way back at the top then your output shaft seal is leaking but if you only see if down at the bottom near the boot then it's the final drive input seal.

[BalancePoint]

Others here have a lot more expertise, but the leak you describe sounds like the garden variety seal leak, not a looming failure of the big bearing at the hub that can potentially destroy the final drive. I have the same leak on my R1100R, and it's not much more than a minor nuisance.

[Mr. Frank]

I've had my pinion gear seal replaced twice and those symptoms match mine. When you clean things up, be sure to slide the boot back and drain and clean it. Then you can monitor the oil level in the final drive. It takes very little oil to make a big mess.

[blaisew]

Good input from all. I'm going to guess that it's a leaking pinion seal as it is just not very wet behind the wheel. 'Think I'll go ahead and have the seals looked at and replaced to see if it will stop. If it comes back, I'll just keep it cleaned up and ride...

[RT Russ]

I've got the same thing going on with a 2002 RT with 18.5k on the clock. I recently pulled the boot back and found very little remaining oil. The Final drive is near text book oil level, tranny is fine. Very little oil seepage made a big mess. I cleaned the boot and I'm now keeping a keen eye on it. Had me really worried that I had a final drive failure coming at me.

[blaisew]

Yep, that just about exactly when I started noticing some leakage, and there was just a little oil in the rubber gaiter. I couldn't see any drop in oil level then, either. Now, it's getting worse, the oil level is going down slowly and more and more oil is on the rear wheel and under the drive housing. Just keep an eye on it; seals don't ever start sealing better once they leak.

[Michael_T]

Has anyone heard of a final drive leak being caused by hitting a pot hole? I was traveling the other day and the cage in front of me stradelled the "tire killer" but i was not looking down and just went into it. Rattled my teeth somethin' fierce.

 

Be that as it may, there is now a puddle of oil on my rear tire. Thought I would ask before taking it to the DeSimmone dealership in south Jersey.

 

Thoughts? Is this still a seal issue - or did I really screw something up?

 

MVT

[Ken H.]

Where is it leaking from?

 

The input 'gator' area, or the seal at the wheel hub?

 

If the later, check for newly introduced wheel play. You may have damaged the crown bearing.

[Jerry Duke]

Maybe I hate leaks more than some, but I don't want my bike to leak, period. It's not supposed to. If something is causing the pinion seal to leak, I want to find it and fix it.

When my pinion seal started leaking I pulled the FD and sent it to Anton. Good thing too, because the shims were out of spec and were putting too much pressure on the gears and could have destroyed them. It came from the factory that way. Anton reshimmed the gears, replaced the pinion seal and all is good with the world. For now....

[AndyS]

Maybe I hate leaks more than some, but I don't want my bike to leak, period. It's not supposed to. If something is causing the pinion seal to leak, I want to find it and fix it.

....

 

Sorry to disagree. You might hate leaks, but unless you have an unlimited budget and are prepared to keep having your bike off the road, then a leak from this input seal is one that some of us MAY have to live with.

 

You might say that it is realy no different than an oil breather venting and deciding to take your bike apart to fix that 'problem'.

 

Andy

[Jerry Duke]

While I don't agree with your analogy, I do agree it's one of the lesser problems we see on these oilheads.

[LDHack]

Consider having Blackstone Labs - www.blackstone-labs.com do an oil analysis of your FD oil. It will provide you information on gear & bearing wear - which is good information to know. They give you a report with results from the analysis, plus a written explanation & recommendations. Hopefully your leak is just a seal leak.

[Unhofliche_Gesundheit]

$22 - that is good price for peace of mind. if you have even more money you can also consider a preemptive replacement of your crown bearing. i have come to the conclusion that this is the best approach to deal with the crown-bearing which i think lacks in the 'reliability/longevity department' (the design is d efficient imho).

not obvious what would be the best interval to do the replacement - maybe 50000 miles?

obviously changing the crown bearing is not going to do anything for a pinion seal leak. obviously also is that if the new crown bearing is installed but shimming is sloppy then you are no further ahead (this is the scenario that befell me).

good luck.

[Boffin]

$22 - that is good price for peace of mind. if you have even more money you can also consider a preemptive replacement of your crown bearing. i have come to the conclusion that this is the best approach to deal with the crown-bearing which i think lacks in the 'reliability/longevity department' (the design is d efficient imho).

not obvious what would be the best interval to do the replacement - maybe 50000 miles?

obviously changing the crown bearing is not going to do anything for a pinion seal leak. obviously also is that if the new crown bearing is installed but shimming is sloppy then you are no further ahead (this is the scenario that befell me).

good luck.

 

I don't think the crown bearing is the culprit here, rather it is incorrect shimming of the crown bearing leading to premature failure that is the issue. Certainly many crown bearings have covered well over 100k miles, whereas bearings replaced without re-shimming have failed in very short order.

 

Andy