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I'm trying to remove the final drive from my '82 R100 but it's stuck and doesn't want to come off. I don't think it has been off since it was installed at the factory. I've tried a rubber hammer, rubber mallet, soaking the rear drive/swing arm junction with Blaster solvent, using heat, and holding a hardwood block on the ends of the four studs and then hammering on the block. Nothing has budged it. Never had this issue before. Suggestions?

Penetrating oil around the bolts and gasket overnight.

esman100 wrote:Penetrating oil around the bolts and gasket overnight.

Tried that last night. Didn't work. I used PB Blaster penetrating solvent. Soaked 'em all down again today.

I'd try a 10mm nut on the two top studs, and the bottom inside stud. If I had three nuts, I'd use one on each of those studs.
Thread them on 90% leaving maybe a bit less than an 1/8" overhanging the stud.
Use a mash hammer, club hammer, or whatever a 10" handle, big fat headed hammer is called.
Give square on 'taps' to the nuts in turn.
Starting with a moderate 'persuasions' to assess effort required.
The weight of the hammer head is the tool of choice.

I'd rather do that, than hit the casing.




Btw you lot, if I had three nuts I'd be a legend wouldn't I.

You might mention to the PO that one need not glue the gasket. Did you try heating the joint?

Duane Ausherman wrote: Did you try heating the joint?

Yep, it worked.

Another overnight Blaster soak to the gasket and studs, a little more heat this morning, a few raps on the studs using a hardwood dowel, and off she came. I bought this bike from the original owner in 1993 so I have no real reason to believe the final drive had ever been off before. The gasket was completely clean - - no evidence of gasket sealer or anything like that. Thanks for the responses.

I would have started with some pounding with my reboundless hammer. If that didn't work easily, I would have then put the axle back in part way to give something for leverage. Then I would have put a long pipe on the axle to extend it. Then I would have put some pressure on it, such as a rope or one of those strong black rubber bungees that truckers use. This would put pressure on it and keep my hands free. I would start heating it up around the joint with a propane torch. As it heated up I think that I would expect to see it starting to part slowly.

I have never had to even put the nuts back on for a safer rap. That is a great idea and am glad that it worked.

Just for general info to all, I highly suggest checking a final drive after 25k miles. The gears will show the wear marks to indicated how to spacing was done. It is only 1-2% that are done incorrectly, but you really don't want to discover the poor spacing after you find a broken tooth in the oil. Or, worse yet, dead in the water while out touring.

One can do this while the final drive in on the bike. Just drain oil, pry off the brake shoes, remove the brake cam and then the 10 nuts. The cover comes of easily for gear inspection. One just needs a new gasket. This is a good time to clean out the drain holes for seal leakage.

Or, keep a good spare final drive available.