Clutch Pressure Plate

[hudson]

Hey guys, well its winter and I'm finally getting at the RMS on my 1971 R75/5. Got the gearbox removed, but now I'm at a standstill. The clutch pressure plate has straight slotted bolts.

What is the best way to remove these without damaging the head on these bolts? I imagine and impact driver would be my friend - anything else? Heat? Any other tips? I am very timid about ruining the heads on these bolts.

I guess I have to remove the engine from the frame as I have no room to swing at an impact driver in there, even with the swingarm and back wheel removed. I see no other way. This is frustrating as what I initially intended was a gearbox & clutch removal job has now turned into complete engine removal.

Any help or tips is very appreciated.

[Kurt in S.A.]

I would first try getting a screwdriver whose blade fit that hole very tightly. You could also used some grinding paste on the tip of the screwdriver. Then holding as much forward pressure as you can on the screwdriver, use an open wrench to engage the square shaft of the screwdriver and try loosening the screw. If there's anyway you can get some penetrant (not WD-40) into the threads, time will help to wick down the threads. Keep applying the penetrant.

Kurt in S.A.

[Tri750]

Those are likely the original bolts. The "new" bolts are Allan head and are about 2 bucks each.
Bmw part # 21 21 1 231 463
You could probably use one of the Harbor Freight hand held impact drivers that you smack with a hammer. But even if you try to use an air or battery impact, rotating the clutch around to where you have the most room to work will help .

Just use a very short burst. Vibration will help loosen any bolt that has been in place a long time.

[hudson]

Thanks guys. I have PB Blaster (not wd 40) to help once I can get a partial thread exposed. I have a hand held impact hammer, but no good clearance to hit it with the hammer. I will try Kurt's suggestion first and if no go, possibly get a small handheld battery/electric driver. Thanks...

[jagarra]

If you have 6 bolts to remove I would remove one and get 3 long bolts with the same thread pitch and nuts for compressing the pressure plate. Then remove the other 2 bolts skipping over one so you have remove them equally spaced. Insert your new bolts and with the nuts holding the pressure plate compressed. Then go after the remaining three bolts. Then you can back off the nuts equally and release the pressure plate.

[hudson]

Thanks Jagurra - yeah I have the longer bolts ready to go to ease it out, just need to get access to the slotted bolts first...

[jagarra]

Sometimes creating a pry point helps. If you look at the bottom of the picture you can see the flywheel stop. If one had a flat plate with a hole to be bolted to the engine you have just created a pry point. If you had a screw driver tip that fit a ratchet handle you could align the whole set up to the screw and then shove something between the back of the ratchet and the pry point to keep it from camming out. It may hold it in till you broke her loose.

[Duane Ausherman]

In really tough cases with those slot bolts, we had to go to extreme lengths. We would put together several socket extensions to reach well back far enough to use our hand impact wrench. The extensions probably totaled 4 feet in length. Then we would have to rotate the flywheel to a certain position for access.

Never use those silly bolts again. Avoid the need for extreme measures.

I have no photos of this procedure, so I hope that I have described it well enough.

[hudson]

Hey Gents - I got to working on the "ol girl this weekend. I got the clutch "slot" screws out. I had do drill one out, the others required tapping the at the edge of the slot counter-clockwise until it loosened. Can I use the replacement clutch bolts (ending in part # 463) from MaxBMW?

Anyway, the reason for getting the clutch out in the first place is to get at the RMS. Between the oil and the clutch dust, it is a mess in there!

My question is what can I use to clean off clutch parts? Can they be submerged or should they just be wiped clean? If anyone has the specs for the plates normal thickness range, please pass along. I would prefer to reuse instead of replacing the entire clutch assembly.

Thanks so much!

Hudson

[Kurt in S.A.]

Haynes shows the service limit as 4.5mm. How many miles on the clutch parts?

The part as 21211231463 is listed as a fillister head screw which appears to be allen heads. Seems like that's perfectly fine.

Kurt in S.A.