bell housing oil leak on K100

[zipster68]

Hi Brickers,
I've got a bit of a engine oil leak from the bell housing weep hole on my '86 K100.  It only leaks when hot.  The rear main seals have been changed in the last 1200 miles (twice) at the dealer.  Any ideas what else could be causing the leak?  Dealer says ride it, says the design won't allow it to get on the clutch.  I just put 1000 miles on it last weekend, and it ran great, saw no appreciable drop in the oil level.
Cheers!

[Martin]

Take it back to the dealer sounds like he is pushing the seal in too far. See bulletin.

Problem: Leaking sealing ring at output shaft.

Cause: An unfavorable set of tolerances may cause the sealing lip of the shaft
seal to rest partly on the chamfered area of the clutch support, with the
effect that a perfect seal cannot be ensured.

Action: Effective from calendar week 14/97, the shaft sealing ring on production
motorcycles will be installed with a projection of
0.5 + 0.1 mm towards the engine block surface.

Service remedy: If a complaint is received, the shaft sealing ring is to be driven into the
engine housing so that this amount of projection is assured.
Modification to special tool BMW No. 88 88 6 111 630

Regards Martin.

[zipster68]

Just wondering if there are other possibilities.  Isn't the block split right where the shaft exits?  If so, couldn't that seam leak?

[Martin]

When the gearbox is removed you should be able to see the leak, you may have to remove the clutch. Is the dealer who attempted to fix it a BMW dealer, and is he aware of the bulletin on seal replacement. My view is that if it was given to the shop to repair a leak, and the leak is not repaired you should not have to pay. If you are unhappy with the service and have payed, demand your money back and go elsewhere.
Regards Martin.

[Laitch]

The rear main seals have been changed in the last 1200 miles (twice) at the dealer.

You write main seals. Does this mean two different seals or the same seal? Is this an engine oil leak or a transmission oil leak?  If this is the seal behind the clutch assembly, it isn't supposed to leak.  If it's a pushrod seal, it isn't supposed to leak. If a second seal was installed because the first one leaked, how does this leaking seal differ from the second and the first in a way that means it shouldn't be changed? Is the dealer actually trying to convince you that it is designed to leak?

The dealer's explanation doesn't hold oil. It sounds as though the service bulletin in Martin's reference was missed by the service department. Print it out and take it to them. Get together all your receipts and documents about the problem. Look at one of these forms. Take this failure of competency seriously. If you do, they will.

[zipster68]

As I was told the rear main seal plus o-ring was changed at the dealer by the PO, and when it started leaking after I bought it, they changed it again under warranty.  It's motor oil, not trans oil.  I'll print out the service bulletin and see if they pushed the main seal all the way in, or left it .5mm out.  The dealer told me when he did this that he didn't think the main seal was the culprit, and that the leak might be originating further up.  It would help if I could find a detailed exploded view of all the seals.  The Max bmw views just don't give me a clear picture.

[Laitch]

. . . that the leak might be originating further up.

  Would that be in the UP? :giggles  I'd ask him, "Where's up?"

[zipster68]

As helpful and intelligent as all of that is, what I could really use is a good and detailed exploded view that shows all of the seals (rear main) and how everything goes together.  All possible oil paths to the weep hole.  Max BMW doesn't cut it.  Not having torn one of these apart, and lacking good documentation, I'm having a hard time figuring this out.

[Laitch]

As helpful and intelligent as all of that is, what I could really use is a good and detailed exploded view that shows all of the seals (rear main) and how everything goes together. 

Maybe your dealer could use one too. :giggles

I know answers can be disappointing here, but the price is right,  :hehehe In the spirit of giving you your money's worth, I'll provide a couple of images. They're helpfully labeled. You'll notice the leak on one of them heads straight for the weep hole. The area surrounding the center shaft is the location of the failing seal and o-rings. A leak above the housing that would infiltrate the clutch area is unlikely. There's no charge for the photo of the transmission; it just shows how the two mate up.

There are also complete diagrams on the web showing the workings of all the internals of the engine and transmission. A literate Google search brings them right up. They are well done would be really helpful, I'm sure.

[zipster68]

Thanks Laitch, that helps a lot.  Best picture I've seen yet, and clarifies some things in my head.  Sounds like the only two probably leaks are main seal or shaft o-ring, both right in that spot.  I'll hit the Google again.
Cheers,
Ray

[Martin]

I reckon they have never seen the bulletin, and as per Laitch where is UP. Unless you have porosity in the engine casing which is highly unlikely, I can only see two possibilities, the seal or the  "O" ring. Without showing him the bulletin I would question him about where UP is, and also on how the seal was installed. If you can't get any satisfactory explanations get your money refunded and go elsewhere.
Regards Martin.

[zipster68]

Dealer says Seal n o-ring have been done 3 times on the bike with the problem coming back each time. They use the factory install tool. Don says this one is something else, and he's stumped. Says best way to sleuth this is pull tranny, clean and dust it, put tranny back and run it. Then pull tranny and look for clues.

[bocutter Ed]

as per Laitch where is UP.

Methinks its an insider. I dont' think Ferndale, Michigan is in the UP.  :hehehe


Google ""up michigan" ...