Final drive rubber boot weeping - HELP

[bwr]

 

I’ve managed to put about 1500 miles on the ’04 RS I bought 3 weeks ago. While all’s going well, I have noticed that the rubber boot on the swing-arm adjacent to the final drive is weeping a bit of oil or grease. Please see the attached photo.

 

This was taken when I got home after a ~800 mile 2-day road trip, mostly highway riding (the bike has over 14K on it now).

 

As you can see, it’s not leaking very much; but, there is something weeping from the boot’s seam. I’ve been looking over my service manual and – unless I’m missing something – there doesn’t seem to be any oil in there. Does anybody have any ideas what this might be? Is oil leading from the final drive into the boot? Or, is this perhaps excessive grease that was used to seal the boot’s lips?

 

Do I have a significant issue here of should I just keep my eye on it? If it is serious, what’s involved in addressing it?

 

Many thanks for any advice. I feel like I’ve got so much to learn.

[bmweerman]

That doesn't look like much oil to me, but I'd pull the boot off the swingaram and see if you had any oil in there indicating a leaky transmission seal..

 

There shouldn't be more than a drop or two of oil in the swingarm under normal circumstances.

 

Good Luck

 

Cameron

[JamesW]

Hi Brian, on a recent ride into the hinterland I noticed the rear boot on my 04RT to be weeping a might and as I was near Clarkston Washington and the world famous Mac's Cycle I stopped in and was told by the service manager that the condition is not at all unusual nor is it anything to be overly concerned about as he has never had or seen this lead to a problem. So, I went on my merry way after cleaning the gear lube off and noted that when I arrived home some 600 miles later that signs of leaking had mostly not reappeared.

I am going to take Mac's Cycle advice and let it go by.

[matanuska]

I wouldn’t worry about it.

 

Check your final drive and transmission oil levels to be sure. However, that amount of leakage appears to be insignificant, so even if it is gear oil, I doubt you’ll see any change in levels.

 

Other than catastrophic failure of one of the seals that causes a sudden loss of level, oil seepage into the swing arm (and out of the boot) is more of a nuisance / aesthetic issue anyways. If anything, it could help lube the drive shaft splines and universals a little better! It’s oil leakage out of the front transmission seal (or rear engine seal) you need to be concerned about, it can ruin the clutch.

[Boffin]

Hi and welcome to the board.

This is a fairly common occurence and comes in two flavours. The oil is almost certainly from the input seal to the final drive. Pull the boot and see how much oil comes out. If it is just a small amount, clean it up refit the boot and relax - some seals tend to weep a bit here. If you get more than an eggcupfull of oil, the seal needs replacing.

 

On the other hand, a US '04 bike with less than 36K miles is still in warranty - let your dealer take care of it on BMW's nickel.

 

Cya, Andy

[ShovelStrokeEd]

There are two potential sources of oil/grease coming from the boot area. The transmission rear seal and the final drive input(pinion) shaft seal. Snip the giant wire tie holding the boot in place and spend a little time cleaning up in there. You can obtain some large wire ties at Radio Shack or most any big auto parts store for a replacement.

 

Most often, it is the pinion shaft seal weeping a bit and, as stated, it is normally not serious. Could be a result of a slight over fill. I have never seen one of these fail utte

[bwr]

a US '04 bike with less than 36K miles is still in warranty

 

Actually, apparently this particular bike was sold in the summer of '03 and according to the dealer is no longer in warranty. A little frustrating because I assumed that it still had the better part of a year to go and didn't think to confirm until after I'd signed on the dotted line. Oh well -- live and learn.

 

Thanks to all for your comments. I'll probably pull the boot just to see what's in there; but, it sounds like it's not a big deal.

[Mr. Frank]

a US '04 bike with less than 36K miles is still in warranty

 

Actually, apparently this particular bike was sold in the summer of '03 and according to the dealer is no longer in warranty. A little frustrating because I assumed that it still had the better part of a year to go and didn't think to confirm until after I'd signed on the dotted line. Oh well -- live and learn.

 

Thanks to all for your comments. I'll probably pull the boot just to see what's in there; but, it sounds like it's not a big deal.

 

The warranty is for 36 months. Summer of '03 would take you to summer of '06. You are way under the mileage limit of 36K miles. It should be under warranty, and your dealer should go to bat for you.

[Wild Bill]

See attachment for a real FD leak… At least I thought so while on a 1600 mile trip…. It had rained that day and made it look wore than it was…. For all that mess, it was only down about ¼ inch. I completed the trip, kept an eye on it and the dealer replaced the seal… That was done at 4000 miles and still no problems 3 years and 30,000 miles later..

 

Good luck…

 

It looks like you may have a minor leak there, but you wont know till you pull the boot back and check for residual oil.. I had almost no residual oil in the boot when it was disassembled..

[DEF]

A minor leak is a minor leak. First, clean the area thoroughly.

 

Next, I would ride to reach operating temperature. Next, with the drain plug removed, flush with ATF to remove any debris in the FD case. Refill with 75W-140 synthetic gear oil with added moly. The moly can cure minor leaking by providing lower friction at the seal lip, increasing the sealing ability. Do not overfill.

 

Then, watch it carefully by routinely checking the apperance of the boot as well as the oil level in the FD.

 

Remember, when checking the synthetic oil hot, it will have greater volume due to the synthetic oil expanding. So, I would always check it cold.

[Mulepick]

and after all that, if you're as anal as I am, get the correct metal bands for both ends of the boot and don't overtighten as your previous wrench did.

 

Bob

[questrider]

I asked this similar question back in July '05:

 

http://bmwsporttouring.com/ubbthreads/showflat.php?Cat=0&Board=UBB1&Number=537018

 

I took it to the dealer a couple of months thereafter for the 12,000 mile service and had the seal changed. Since then, I don't get the real bad stains on the paralever swingarm to the right of the boot like I did in this picture, but it still weeps a little bit under the boot on the stabalizing suspension part of the swingarm. (I'm probably not using the right terminology!)

 

 

Of course, I compound this issue with my own problem which is I do not wash my bike very often, and if it weeps a little bit, and then I ride in the rain, and then continue to ride for miles and miles and miles, it looks real dirty and worse than it probably is.

 

I wish it didn't weep or leak at all, but from the comments in both of these threads, this is again another one of those "they all do that" (TADT) issues.

[Ken H.]

another one of those "they all do that" (TADT) issues.

Yeah, and they haven't solved it yet either. Our '05 R1200GS is weeping a bit now too.

[tom collins]

excuse me for not reading all of the prior posts, so this may be a repeat. my 04 started weeping just like that at about 17k miles. under warranty, they replaced the seal up at the tranny area, the oil had travelled down the shaft. if you are under warranty, have them do that.

 

tom collins