low pedal engagement, not bracket, not master, not slave

[taiden]

0.65" before I finally bled the clutch. I have to admit that I didn't get a chance to check again before the end of the day. Pedal feel was significantly better than when it was at 0.65" though I can tell you that much.

[taiden]

It is in fact the pivot pin.

Stuck a small allen key backwards through the pivot pin hole. I was able to actuate the clutch without the plastic sleeve moving. I figure this means that (as moosehead suggested), the head of the pivot pin is completely sheared off.

I wish I had checked this sooner. Took about 30 seconds to check.

The good news is that my clutch system is completely bled.

Do you have any idea how tempting it is to just tap it with a 1/4x20tpi tap, round off the tip of a bolt, and thread it in?

So... tempting...

but in the spirit of this well maintained car, I SHALL NOT BREAK!!!

[mooseheadm5]

Do you have any idea how tempting it is to just tap it with a 1/4x20tpi tap, round off the tip of a bolt, and thread it in?

Don't be ridiculous.

Use metric fasteners.

[taiden]

[Mike W.]

It is in fact the pivot pin.

Stuck a small allen key backwards through the pivot pin hole. I was able to actuate the clutch without the plastic sleeve moving. I figure this means that (as moosehead suggested), the head of the pivot pin is completely sheared off.

I wish I had checked this sooner. Took about 30 seconds to check.

The good news is that my clutch system is completely bled.

Do you have any idea how tempting it is to just tap it with a 1/4x20tpi tap, round off the tip of a bolt, and thread it in?

So... tempting...

but in the spirit of this well maintained car, I SHALL NOT BREAK!!!

NO NO NO, you can't do that. The wheels will fall off and it will catch fire!!!

Well, probably not. And while it might create problems sometime in the future, for now it sounds like a reasonable approach to avoid pulling the tranny, which is a full PITA. I'd do it.

[taiden]

Hmm. I haven't started pulling the transmission yet. Is my idea insane? My fasteners book is MIA so I don't have the resources to calculate acceptable axial load for a threaded steel fastener in a cast aluminum assembly.

[demetk]

Sounds interesting. Waiting for what you come up with as a solution. This comes to mind.

[taiden]

The metal pivot pins seem to all be silicon bronze. If my memory serves me, this material's surface is naturally low friction. I haven't seen anyone use steel for this part, and I assume it's because it would increase wear on the clutch fork. Clutch forks are cheap. The plus about having a threaded pivot is it would be adjustable. I don't know. I'm still on the fence.

[mooseheadm5]

The 850i pivot is stainless steel.

[taiden]

Whoa! That's good enough for me. Thanks again moosehead.

Quick question, what's the function of the spring? Just to keep it in place?

[mooseheadm5]

Keeps the clutch fork in contact with the pivot to keep it from rattling.

[Mike W.]

Broken record, but if you tap it and screw something in from the back use locktite. Preferably with a locknut. You don't want any movement, it'll strip the aluminum as often as you push the clutch in.

You might wear thru in a couple of years, but release arms are cheap if you don't already have any spares. Grind the end to a ball shape, polish, maybe add a dab of grease and drive away.

[mooseheadm5]

I wonder if one of these would work.

http://www.sdp-si.com/D785/PDF/D785HW019.PDF

[taiden]

That's pretty much what I'm imagining. I have both a 1/4x20 tpi and a 3/8x16 tpi tap. If either will match the hole I'm going to use a hex head stainless bolt with a locknut.

[1st 5er]

This I gotta see.

Pics please.

[taiden]

I'm doing it.

First I pushed the remaining bit of plastic into the bellhousing. I figure another small bit of plastic bouncing around in there isn't going to hurt.

Hole is 0.305" in diameter.

3/8" x 16 tpi tap was $8 and takes a 0.313" (5/16") hole.

I am confident this fastener size is more than enough for this job.

Updates as I continue...

[taiden]

Just did a test run with a 0.297" hole in a junk cast aluminum water pump. Tapped just fine. I'm going to run the 3/8" x 16 tpi tap without any extra drilling.

[taiden]

Got the hole tapped and got an allen head bolt in there. Clutch disengages beautifully now and the action is silky smooth.

Cost: bloody knuckles and $15

[1st 5er]

This I gotta see.

Pics please.

[taiden]

I'll snag some pictures when I go to do the guibo.

The point is that if anyone else decides to do this, the hole is perfect for a 3/8" x 16 tpi tap. Figure out how to hook the tap up to a stubby ratchet though. Otherwise it's impossible. I did this by holding the tap in a backwards 3/8 drive (male) 1/4 drive (female) adapter and an 11 mm 12 point socket.

Also, the locknut interferes with the bellhousing, so if you can source a smaller nut for the 3/8" fastener, it will probably work best. And finally, if you get the 'set screw' style fastener from McMaster in a good length, this will be the ultimate best.

I doubt this has anything to do with it, but there was an on/off throttle clunk before and it seems to have gone away since I did this?

awkward.

[Mike W.]

Got the hole tapped and got an allen head bolt in there. Clutch disengages beautifully now and the action is silky smooth.

Cost: bloody knuckles and $15

[taiden]

I'm ordering 2" long set screw style fasteners with skinny jam nuts. Should clear the bell housing just fine.

They only come in packs of five, so if anyone decides to do this to their transmission let me know. I'll sell the fasteners for cheap.

[mooseheadm5]

I'd go ahead and use loctite as well. Just make sure you are not accidentally preloading the release bearing. That would be bad.

[taiden]

Valid point but isn't the slave cylinder supposed to relax enough to avoid that issue?

[mooseheadm5]

Valid point but isn't the slave cylinder supposed to relax enough to avoid that issue?

It gets to the point that it is bottomed out if you move the pivot too far forward. It can also make the clutch feel funny.