Oil leaking from final drive 98 R1100RT

[mark1rob]

Returned from a ride tonight and as I was pulling into the driveway I thought I smelled gear oil. After I pulled it up on it's center stand I noticed oil puddling on the rear tire and down. It looks like it is coming from the final drive. It is dark so I cannot be for cetain where it is coming from but it definitly smells like gear oil. Any ideas and what is going to be involved in repairing this?

[RTCHIEF]

I'd check the final drive to see if that is where it is leaking.

[SKYGZR]

How many miles? Inner rear roller bearing race/assembly finally gave way to failure on the K awhile ago. Located a used low mileage unit as a replacement, as that bearing assembly would be difficult to repair.

[AndyS]

Time to check your FD.

With the bike on the centre stand and the rear wheel off the ground, try grabbing it and trying to twist it sideways and see if you can feel any movement (I am not talking about rotational movement but lateral movement).

If you do, then you need to get someone to really push down hard on the rear brake. This in effect locks the Rear wheel and the FD as one piece due to the brake calliper.

Now at the same time, try to do the same check again. If you still get movement, then your FD pivot bearing is worn/needs adjusting.

If the movement stops, then your FD main crown wheel bearing is shot.

 

Next maybe, remove the wheel and see if you can see if the oil is coming from the oil seal around the FD output.

 

Andy

[breyfogle]

.... it definitly smells like gear oil. Any ideas and what is going to be involved in repairing this?

 

Gear oil on the FD can come from three places. The Transmission output seal can leak tranny oil down the inside of the swing arm and out past the boot. The FD can also leak oil out past its input seal, sometimes called the pinion seal. Fixing either of these is relatively straight forward. If, however, the FD is leaking oil past the "big bearing" seal located where the FD mates with the real wheel (under the rear disk), you have either another simple seal replacement or, more likely, an output bearing that is failing (its bits & pieces tend to ruin the seal).

 

You need to clean everything as good a possible and determine where the oil is coming from.

 

 

[Trobinson]

.... it definitly smells like gear oil. Any ideas and what is going to be involved in repairing this?

 

Gear oil on the FD can come from three places. The Transmission output seal can leak tranny oil down the inside of the swing arm and out past the boot. The FD can also leak oil out past its input seal, sometimes called the pinion seal. Fixing either of these is relatively straight forward. If, however, the FD is leaking oil past the "big bearing" seal located where the FD mates with the real wheel (under the rear disk), you have either another simple seal replacement or, more likely, an output bearing that is failing (its bits & pieces tend to ruin the seal).

 

You need to clean everything as good a possible and determine where the oil is coming from.

 

 

breyfogle, you say the pinion seal is easy to replace. Do you have a write-up or link to a how-to? I've searched and this is the best that came up. I know my '96R1100RT is leaking at the main seal as well as the input shaft seal so I figure I may as well do both if it's relatively easy.

 

Tom

[AndyS]

In all honesty i'd say that if the input seal is leaking, give the housing a good clean up and then monitor it. The amount these thing leak nearly always looks MUCH worse than it is.

Even though that input oil seal is only a £8 item, in reality works out to be much more of a headache.

[dirtrider]

Morning Tom

 

First, clean it up, then FIND THE LEAK. Look at the final drive, rear shock, & air box drain for the leak origin.

 

Usually ends up being the wheel side (big) seal or the pinion seal.

 

If a pinion seal is leaking then that is a difficult home repair without the BMW special tools.

 

If a wheel side seal then that is a pretty easy repair at home. (unless a bad crown bearing is causing the seal to leak).

 

A LOT OF old BMW 1100/1150 pinion seals seep a bit (not an outright leak but a slow seep into the boot).

 

I have seen a number of 1100/1150 pinion seal seeps stop seeping when the gear oil was changed back to non synthetic gear oil.

[The Rocketman]

If you can see this link, it might help to explain a few things:

http://www.chromeheads.org/discus/messages/6/438604.html?1265644060

 

Hopefully yours is similar to our R1200C final drives.

[Trobinson]

Rocketman, I'll look at the link later, but I'm pretty sure the 1200 final drives are a bit different.

 

DR,

 

I have confirmed the main seal leak and also know the pinion seal seeps into the boot. If the pinion seal is not as simple as I hoped I'll leave it alone and just do the main seal. Thanks for the input.

[Trobinson]

I just looked at the link and I was incorrect. The internals are pretty much the same. I do not intend on going that far as I'm sure my bearing is fine - no play at all.

 

I'm wondering about the guy who did the write-up not going through adjustments for the new bearing pre-load. I understand this is critical to bearing longevity and not an easy task.

[The Rocketman]

I will ask him and get back to you.

[The Rocketman]

My friend Russ says:

"Tell him if he thinks my way is not appropriate, don't do it!

I replaced my seal and bearing at 24K and now have 94K - with no problems..

Tell him to replace both seal and bearing - the ONLY reason the seal will fail is if the bearing is "wobbling".

The bearing is extremely high precision compared to the machining of the case, the shims make up for the machining variance and thus no need for the adjustment unless you are a glutton for punishment."

 

[dirtrider]

My friend Russ says:

 

"Tell him if he thinks my way is not appropriate, don't do it!

I replaced my seal and bearing at 24K and now have 94K - with no problems..

Tell him to replace both seal and bearing - the ONLY reason the seal will fail is if the bearing is "wobbling".

The bearing is extremely high precision compared to the machining of the case, the shims make up for the machining variance and thus no need for the adjustment unless you are a glutton for punishment."

 

Afternoon The Rocketman

 

I can agree with the don't do it that way part.

 

I have seen many seals fail without having the bearing be bad or wobbling.

 

As far as not shimming the new bearing-- that is a BIG crapshoot. It doesn't need to be shimmed IF the original bearing preload was set up properly ( an awful lot weren't set up correctly as new & that is why a lot of bearings failed)

 

It also assumes the new bearing is EXACTLY the same as the original & the original was set up correctly (do you feel lucky??)

[The Rocketman]

That's exactly why I sent my last one to Bruno. Took forever and a day to get it back, but he guarantees his work for I think 10,000 miles, and I'd heard nothing but good things from others who sent him FD's to rebuild, before I sent him mine.

[AndyS]

Hi Rocketman, a 10000 mile guarantee isn't much of a reassurance on an item that even when bad will do 10500!

I too believe that shimming is critical PARTICULARLY if you have had that unit fail - because that is most likely why it failed.

[The Rocketman]

The dealer gave me a 2 year parts & labor warranty when they rebuilt mine, and it failed within 600 miles, then again at about 1,000 miles. The aggravation just wasn't worth going back a 3rd time. I never heard of Bruno before this, but have never heard of any FD's being returned. Maybe he knows how to rebuild them better than factory trained BMW dealers? I would think they'd both shim it; maybe Bruno just shims better?

[Trobinson]

My friend Russ says:

"Tell him if he thinks my way is not appropriate, don't do it!

I replaced my seal and bearing at 24K and now have 94K - with no problems..

Tell him to replace both seal and bearing - the ONLY reason the seal will fail is if the bearing is "wobbling".

The bearing is extremely high precision compared to the machining of the case, the shims make up for the machining variance and thus no need for the adjustment unless you are a glutton for punishment."

 

Rocketman,

 

Wow, didn't know I was going to piss off your friend (at least it seems I did). Anyway, my question was based on much research on this issue and was not out of ignorance. As others mentioned, if the preload isn't right it is likely your bearing is going to fail early. Also, why on earth would I replace a bearing that is tight? Seals fail for reasons other than a bearing failing. Wear from the rotation alone will do it.

 

Tom

[The Rocketman]

You can't piss off Russ. He's been wrenching on bikes for many years, has a bit of patience (but not a lot, especially with me) and always seems to have the right answers. Don't sweat it.....

[Trobinson]

Yeah, re-reading his post I took it a bit wrong. Or maybe it was just my attitude that day. Anyway I always appreciate input from others.

[ogjimbob]

My friend Russ says:

 

"Tell him if he thinks my way is not appropriate, don't do it!

I replaced my seal and bearing at 24K and now have 94K - with no problems..

Tell him to replace both seal and bearing - the ONLY reason the seal will fail is if the bearing is "wobbling".

The bearing is extremely high precision compared to the machining of the case, the shims make up for the machining variance and thus no need for the adjustment unless you are a glutton for punishment."

 

Afternoon The Rocketman

 

I can agree with the don't do it that way part.

 

I have seen many seals fail without having the bearing be bad or wobbling.

 

As far as not shimming the new bearing-- that is a BIG crapshoot. It doesn't need to be shimmed IF the original bearing preload was set up properly ( an awful lot weren't set up correctly as new & that is why a lot of bearings failed)

 

It also assumes the new bearing is EXACTLY the same as the original & the original was set up correctly (do you feel lucky??)

I can only quote my experience, my FD seal failed because the ball race collapsed and the frags sliced the seal into Fillets! no wobble even at that point! as to shimming, has anyone accurately measured the various bearings for consistency? if the bearings are all in spec then I wouldn't be too worried about the original set up which made 16 years and 65K miles .

[dirtrider]

clip-- has anyone accurately measured the various bearings for consistency? if the bearings are all in spec then I wouldn't be too worried about the original set up which made 16 years and 65K miles .

 

Afternoon ogjimbob

 

The only way to do that would be to remove the original bearing (before any wear & before failure) then compare the bearing dimensions & assembly preload to a series of new replacement bearings. That would include doing both the 17 & 19 ball bearings.