S52/ZF UUC LTW Flywheel E34 OEM Clutch won't disengage

[hammslice]

Trying to get my S52/ZF swap going. Engine runs. When the trans is in neutral everything behaves as it should. The car will shift through all the gears fine, but with the clutch depressed the wheels still turn.

Has anybody run across this? What'd you do to fix it?

Here is my bimmerforums.com post for some background.

http://forums.bimmerforums.com/forum/showthread.php?t=1639129

[e46s54dr]

Are you talking about the rear wheel spinning when the rear end is jacked up and in neutral? Because alot of cars will do that regardless of it being in gear or not. If it spins like the clutch is engaged even in neutral, I'd say that you might have installed the clutch plate backwards?

[Adrian_Visser]

Bleed the clutch hydraulic system again.

[Eric]

what clutch slave cylinder are you using?

I had the same symptoms with my euro S50 swap when using a 525 slave cylinder sourced from a parts yard. The M3 was model specific for the clutch slave.

[hammslice]

Plan on rebleeding this afternoon. I am using a new e36 325 slave cylinder.

I understand that some friction drag causes the wheels to spin, but this is actual engagement. Car of the ground, in gear, pull the parking brake, and it kills the engine.

I've been talking to Rob @ UUC and those conversations led to a possibly defective PP, but the more I think about it, I get less confident in the bleed we did.

People with this set up, E30 master cylinder is compatible?

Thanks for the replies.

[jahnaboi]

Sounds more like a bleeding issue. It took myself a good long 30 minutes of bleeding to get all the air out on my s52/zf setup.

[Matt-B]

yea took me 30-40 minutes

[hammslice]

So I have been out of the country for a few months, but while I was home for the holidays I tried to resolve this. No luck however. I used Phoenix systems reverse bleeder and pumps fluid up through the line and there are absolutely no bubbles coming out of either end anymore.

The clutch is definitely partially disengaging. With the car in the air, trans in gear, and clutch pedal depressed, I can, with significant grunt, rotate the rear wheel. The clutch is still holding enough to kill the motor and prevent shifting while driving.

Do I need a different master cylinder (using e30 325is stock)? Are there slave cylinders with different (longer) throws? I tried using a stock e36 M3 slave as well and got the same result.

[e30rapidic]

Which throwout bearing are you using?

[hammslice]

Stock e34 that came with the kit from UUC.

[hammslice]

Also of note, I replaced everything I could think of: fork arm, pivot pin, retaining clip, pilot bearing, throw out bearing, and slave cylinder.

[5mall5nail5]

Stupid question but is the clutch in the right way?

[hammslice]

It is. Clearly printed on the clutch and verified 3 or 4 times.

[Mr.SWISS]

Dude if you are using a zf you HAVE to use the ZF slave. 96-99 M3/328i ONLY! no e36 325!!!!!

[hammslice]

I was just going on the info from UUC. "Note: slightly lighter clutch pedal effort may be experienced in M3, MZ3, Z3 2.8.*To maintain original clutch pedal feel, use the E36 325i slave cylinder (click here for part number and diagram), All other models retain original slave cylinder."

I got advise from a shop in town here to use the M3 slave and they had one that they sold me. I got the same result. I put the 325 one back on because it was in better shape. Maybe next time I am home I'll have to get a new M3 one from the dealer...