Final drive housing - olil leaking from gaiter?

[jora112233]

Hi all-

 

Have got some oil leaking from the final drive, frrom under the gaiter. I have only one gaiter clamp at the larger end of the gaiter, but not one at the smaller end....

 

Should the gaiter clamps be sufficent to stop the leak? or are their additioanl oil seals within the final drive?

 

I guess my question is if so, are these easily replacable? have refered to my trusty Haynes, which states that if the drive housing gears, bearings, o-ring or oil seal require attention the complete unit should be taken to a BMW dealer wo would have the expertise to overhaul the assembly...

 

Is this necessary to replace the seal? if so is it a big/expensive job?

 

Regards

 

Jon

Cardiff

UK

[Boffin]

Hi and welcome to the board

 

There are two possible sources for the oil you see, the gearbox output seal and the FD input seal. To tell which you have, pull the large end of the boot back and look up the shaft tunnel. If the bottom of the tunnel is dry the oil is coming from the FD, if wet the gearbox.

 

If the gearbox seal is the culprit, you need to drop the swingarm to get to the seal which is an easy fix.

 

If however (as is more likely) the oil is coming from the FD then the fix is much more difficult and really needs special tools / jigs to do.

 

If there is a lot of oil coming from the seal it will need attention but this is not common.

 

It is however very common for this seal to weep and the weep will often come back in a short time if the seal is replaced. The good news is that they will gently weep for tens of thousands of miles without ill effect. I found my seal has recently just about fixed itself after I stopped using 70W145 synthetic oil and started using (the reccomended) 80W90 to GL5. In fact I use Halfords brand 80W90.

 

If like me, you choose to do nothing, just clean up the muck, put the boot back on using plastic ties and check that things have not worsened at service time. Mine has been gently weeping for over 40,000 miles now...

 

Andy

[flars]

yeah - what Andy said. leak from front of bike is not very common, but a leak from the rear (from the FD) is quite common. Mine has weeped a tiny amount for 80,000 miles, but the gaiter usually keeps it in. I pull the small side of the gaiter and let it drain out then wipe the inside of the gaiter with a rag every year or so. Then I use a plastic wire tie to clamp the rear of the gaiter. BTW - I use three plastic ties zipped together end to end to hold the front of the gaiter since I don't have one that is long enuf.

[AndyS]

Hi all-

 

Have got some oil leaking from the final drive, frrom under the gaiter. I have only one gaiter clamp at the larger end of the gaiter, but not one at the smaller end....

Good Afternoon Jon, It's good to have you on board - especially from these shores!

Pop the gaiter off (you can probably just ease it off complete with the Tywrap - and get it back on again with the original if you are fortunate).

Use a flashlight and see if you can identify if it is migrating down from the gearbox. If it is, then that is rare and not so good. Come back to the forum with the update for the next stage if it is from that end.

Generally it weeps from the rear drive and most of us carefully clean it up, replace the gaiter and forget about it.

Bye

Andy

[BMT]

I'll concur with the others and add that I had two replacement final drive seals under warranty, to no effect.

 

My magic routine now involves using the standard oil spec. (it's actually SAE 90) and slightly underfilling the final drive: a tad below the thread on the filler hole.

 

For the last two services, there has barely been enough seepage to wipe out, in spite of some higher temperature, higher speed long runs, which used to make a hell of a mess.

[jora112233]

Hi All (again!)

 

Have pulled back the gaiter and no sign of any oil in the bottom of the shaft tunnel? (although assume it is therefore comming from the FD, don't really understand where it's comming from

 

Anyway - as it looks like it's the FD, have cleaned out the oil (spilling my white spirit all over the floor! good grief...)

and have put the gaiter back in place with some new ties.

 

When I did pull the gaiter back about 5-6 ML of oil spilled out. does this sound a lot?

 

Thanks Andy L, Andy S, Flars and Le Nick for your quick response - really appreciated.

 

Jon

Cardiff

UK

 

 

 

[Boffin]

5-6 ML is nothing to worry about. Clean up and enjoy.

[Linz]

I used to have this issue when I used fancy-schmancy synthetic multi-weight oil in my FD. Oil would be smeared all over the FD after a run...

 

I asked about it here, a Tech Mod suggested that I use straight 90 weight oil.

 

I bought a bottle of straight 90W Shell Gear Oil and have not had a leak in 15,000Km since.

 

The factory workshop manual states the correct grade is straight 90W. I think it's right.

 

Linz

[Mark K]

Wow that was cool!

 

Question posed, answered clearly and concisely, problem remedied in what.......six hours?

[jora112233]

 

Couldn't agree more......

 

Thanks everyone

 

 

Jon

Cardiff

UK

[BMT]

Couldn't agree more......

 

Thanks everyone

That's good -- we can get the invoice raised. ;-)

 

Just an additional detail: I don't bother washing everything surgically clean -- a wipe out with a dry rag or kitchen roll is fine.

[BMT]

Wow that was cool!

 

Question posed, answered clearly and concisely, problem remedied in what.......six hours?

... and from three continents!

[Mark_Turner]

 

Thanks for posting this question, I just starting seeing this myself on my 99 RT and wasn't sure if it was anything to really worry about. I know for me it's the FD gear oil cause I just changed it to regular 90W oil. It was previously filled with the red synthetic stuff. Guess I'll just keep a watch on it.