'85 K-100 tranny output shaft seal

[Librarian]

Doing the spline lube thing :snore and pull off the swingarm only to find that the rear main seal of the trans is leaking. There's no need to do anything to the trans, so the question becomes: can I replace the rear main seal without splitting the tranny case? If so, how? :scratch

[roy]

Doing the spline lube thing :snore and pull off the swingarm only to find that the rear main seal of the trans is leaking. There's no need to do anything to the trans, so the question becomes: can I replace the rear main seal without splitting the tranny case? If so, how? :scratch

Yes you can change the seal without splitting or removing the tranny.

Measure the depth of the seal from the tranny face. I can't remember if this seal has a stop in the housing or not.
Carefully drill two pilot holes for sheet metal srcews in the seal 180 degrees apart. Install the sheet metal screws and then using the screw heads carefully pry the old seal out.

Install the new seal to the proper depth.

Roy

[Librarian]

Thanks, Roy! Much easier than a disassembly. Leaves more time for :drink

[Librarian]

OK, so a few questions from a noob to tearing apart my brick:

1) Taking apart the clutch to do the spline lube, and when I removed the nut holding on the flywheel, and jostled out the o-ring, all of a sudden there was crankcase oil coming out of the opening. Now mind you, there had been no sign of oil there before, and I hadn't bothered to drain the crankcase prior to doing this, so the question is: do I have to replace the rear main seal or is that area supposed to be bathed in oil? I'm betting it is.

2) Looking at the Clymer's description of the clutch and they have three factory marks, one each for the pressure plate, the spring, and the housing, to show the heavy spots. You are supposed to have them 120 degrees apart to balance the assembly. Mine has no mark on the housing and the other two were assembled 180 degrees apart. Is this because the housing is perfect, or....? How do I tell and how do I fix it if it's wrong?

3) Do I really need to replace the six bolts that hold the clutch together?

4) How do you get out the oil seal inside the tranny input shaft that keeps oil from going forward along the clutch release rod?

5) What's better (i.e. cheaper) than using the special BMW tool to align the clutch plate during reassembly?

[roy]

OK, so a few questions from a noob to tearing apart my brick:

1) Taking apart the clutch to do the spline lube, and when I removed the nut holding on the flywheel, and jostled out the o-ring, all of a sudden there was crankcase oil coming out of the opening. Now mind you, there had been no sign of oil there before, and I hadn't bothered to drain the crankcase prior to doing this, so the question is: do I have to replace the rear main seal or is that area supposed to be bathed in oil? I'm betting it is.

You don't have to remove the clutch basket (drive plate) to do the spline lube. Yes the main seal is below oil level so this is normal.

2) Looking at the Clymer's description of the clutch and they have three factory marks, one each for the pressure plate, the spring, and the housing, to show the heavy spots. You are supposed to have them 120 degrees apart to balance the assembly. Mine has no mark on the housing and the other two were assembled 180 degrees apart. Is this because the housing is perfect, or....? How do I tell and how do I fix it if it's wrong?

Did you mark the parts before dissassembly? Unless you had some severe vibration I would Install them the same way they came out.

3) Do I really need to replace the six bolts that hold the clutch together?

I don't think so. The large nut that holds the clutch basket in place must be replaced though.

4) How do you get out the oil seal inside the tranny input shaft that keeps oil from going forward along the clutch release rod?

Very carefully. I finally managed to get a small hook behind the one side and kind of tip it so that i could then hook it better and pulled it out. It was a pain in the butt. be careful on the install that you damage or fold the seal lip.

5) What's better (i.e. cheaper) than using the special BMW tool to align the clutch plate during reassembly?

If you have access to a lathe make your own. You just need to correct diameters to align the clutch to the pilot bearing other wise I am not sure if you could eyeball things close enough.

Good luck

Roy

[Librarian]

Thanks again, Roy. In your honor: :drink

[rjhowe]

I just replaced the clutch disc on a new to me K75S. I got lucky with aligning things but I had some help. Brian Curry suggested I buy bolts the same size as those that hold the transmission housing in place and grind the heads off to make studs. I used the studs to slide the transmission into place. With the studs holding the weight I could gently slide things together. This was a great suggestion!

I used the screwdriver in the tool kit as an alignment tool. This is the lucky part. The shaft fits into the small hole in the clutch spring and the bottom of the handle, when pushed against the clutch plate splines, allows a good view of relative alignment.

Hope this helps. I am obviously new to the MOA. I was really pleased with the way things turned out. I thought the alignment tool, and other special tools would prevent me from doing the job myself.

You can reuse the bolts, but I think the washers should be replaced. I replaced both so I have 6 extra bots for...?

Hope this helps, have fun.
Jeff
88 K75S