Not your typical clutch issues. Help!

[Reckless_Havoc]

Hey guys, I completed an S50 swap with ZF trans and oem sachs clutch kit over a year ago. Drove the car around for quite a while until my wife drove it through a field and drug the exhaust out from under it. Then continued to drive thus bending the shit out of the exhaust.

While waiting for funds to build a new exhaust (didn't like the original) I pulled the motor to reseal the oil pan and rear main. In a vicodin induced haze one night (just had some wisdom teeth pulled) I decided to put the trans back on. In my amazing wisdom I put the friction disc on backwards. Put everything back together and bam, clutch wouldn't work. Tried to pull the trans back off and it was majorly seized. Pulled motor and had to cut the bell housing to unbolt the clutch. The friction disc was seized on. So with a new transmission and new friction disc I put everything back together.

Now the clutch doesn't completely disengage. I've replaced almost everything. All the hydraulics are brand new including a ss clutch line. New friction disc and pressure plate. I've had two mechanics try to solve the issue, neither were able to. Here's the things I've done below. Any help would be greatly appreciated. Btw this transmission has worked on this motor just fine in the past. I had replaced it due to bad shift detents early on in the swap, fixed those and am now using it again. Below are the things I've checked.

T/O bearing and pilot bearing both work fine and move smoothly. T/O is correctly oriented. Replaced an already new pressure plate and friction disc. Custom threaded an adjustable pivot pin and maxed it out. (added a little over 1/4") This moved the engagement feel of the pedal way up higher, but even bottomed out won't disengage. Alignment dowels are on the engine block.

The only things not new are the dual mass flywheel and the transmission. All other parts are oem and have been replaced. The car can be driven if you start it in gear, it even shifts relatively easily while driving, but you cannot put it in gear while at idle.

Whew long story but there it is. Please don't post anything about bleeding the clutch or if the T/O bearing is turned 90. Both are correct. It's been bled every way from Sunday by me and others. Hydraulics feel normal when the clutch is depressed. At this point I'm considering a new flywheel and or transmission as these are the only things that haven't been replaced.

Thanks for the help r3v!

[jt223539]

Did you keep the same transmission after you cut he bell housing off? When you were messing with the TO did you completely remove it and inspect it? I am not asking this because I believe you have installed it incorrectly. I ask this because I installed my clutch disc backwards when I did my swap (dumb mistake), which caused my clutch disc to rub the end of the input shaft sleeve cover (see picture below), which in turn mushroomed the end of it not allowing the TO to slide all the way down it. Which stopped the clutch from completely disengaging.

Sounds like you might have a similar issue. However without pictures it is hard for me to exactly figure out what the issue is.

Here is that picture:

The part I am talking about is just above the brush. it normally bolts inside the bell housing and coverr part of the input shaft.

[e30rapidic]

did you replace the clutch disc with the exact same model? I put the stock clutch disc in once with the a clutchmasters pressure plate and had the same issue. There is only 2-3 mm difference between the clutch masters disc and the stock disc but it wouldn't release at all. I have a picture showing the difference in thickness between the two on my phone

[Reckless_Havoc]

Did you keep the same transmission after you cut he bell housing off? When you were messing with the TO did you completely remove it and inspect it? I am not asking this because I believe you have installed it incorrectly. I ask this because I installed my clutch disc backwards when I did my swap (dumb mistake), which caused my clutch disc to rub the end of the input shaft sleeve cover (see picture below), which in turn mushroomed the end of it not allowing the TO to slide all the way down it. Which stopped the clutch from completely disengaging.

Sounds like you might have a similar issue. However without pictures it is hard for me to exactly figure out what the issue is.

Here is that picture:

The part I am talking about is just above the brush. it normally bolts inside the bell housing and coverr part of the input shaft.

Different transmission, but I did verify that there wasn't any damage on the sleeve after reading your reply. The T/O bearing slides on and off without any resistance. Thank you for the idea, everything is worth investigating at this point.

did you replace the clutch disc with the exact same model? I put the stock clutch disc in once with the a clutchmasters pressure plate and had the same issue. There is only 2-3 mm difference between the clutch masters disc and the stock disc but it wouldn't release at all. I have a picture showing the difference in thickness between the two on my phone

The first shop I took it to did use a factory 95 m3 friction disc. I pulled it today and double checked the part numbers. So the pressure plate and friction disc are sachs parts. It does feel like a 2-3mm difference would logically be the problem. It's as if the pressure plate isn't able to fully release the tension from the friction disc. With the additional leverage from the adjustable pivot pin, I can't imagine the T/O bearing isn't being pushed against the pressure plate as far as possible. Do you by chance have the thickness measurements of your friction disc?

Personally, I'm leaning towards some damage to the dual mass flywheel, but I'm not really sure of a way to inspect it without having another one on hand. I can't see any visible damage to it.

I'm considering buying a lightweight flywheel/clutch kit from UUC due to the high cost of a new OEM flywheel.

Everything is oem on the car (for a 95 m3) with the exception of the ss clutch line from UUC.

[jlevie]

This could be a bad master cylinder.

[Reckless_Havoc]

This could be a bad master cylinder.

All the hydraulics are brand new OEM parts. Hydraulics feel normal, no dead spot, firm pedal, pedal returns properly as well.

[Reckless_Havoc]

Just a follow up, in case someone else runs into this issue. The dual mass flywheel had gone bad. The car sat for a few years before I finally bought a flywheel and clutch kit from UUC. Problem solved. Hope this helps someone in the future.