nts472

I'll start from the beginning, this project began as a car with a 1.8TQ tiptronic..it now has a a 2.8Q (96) manual transmission matted to the 1.8t

Everything went smooth in terms of pilot bearing and ecu issues. It runs fine except that I can't get the clutch to disengage fully. This is where I'm at:

btw, I don't pull the tranny, I take out the entire engine/tranny out of the car, its just easier for me.

I have ruled out the hydraulics because I rigged up a screw device to actuate the clutch mechanically. At max push on the release arm I need a good bit of force to make the clutch slip. Its still clamped through the viewing windows of the transmission.

I've ruled out the operation of the pressure plate and disk (all OEM 1.8t) because the I've actuated the flywheel,clutch, pp combo on a press and I can release it enough to move the clutch disk around with my fingers.

I've changed the release arm, tried a different flywheel, played with pivot ball shims and nothing takes me past that point of disengagement. I'm truly out of ideas.

As far as I know the 1.8 and 2.8 5sp has the same geometry at the bell housing. And I know someone who has done it successfully.

Can't anyone toss me an idea?

jschick

just a thought, are you using all clutch components from the 2.8? master and slave?? or are you using a slave from the 1.8? I have not checked part #'s to see if they are different or not but I would assume you would need a matched set of Slave/Master cyl's. my only other thoughts would be pedal movement??
Good luck!

nts472

There are 2 variants pre 97 (metal body) and post.. I've been using the type that came with the transmission, the post 97 (abs body). They are the same functionally.

But more importantly i've bypassed the hydraulic system completely. Like I said I've been using an adjustable threaded rod that is capable of pushing the release arm beyond what the slave could do.

600whpA4

Just make sure your not pushing the fingers too far causing them to bottom out on the disk, that will cause the disk to spin with the PP/flywheel.


Which flywheel did you use and was it a sprung or unsprung disk that you installed? Disk could be hitting the bolts if your using a flywheel with exposted bolt heads.

nts472

I hit the "barely dissengage" part at about the normal pedal point when it was all together on the car.. the thing is beyond that no more dissengagement

with my mechanical pushing on the release arm its far from bottomed out to hit this point

on a press the clutch disk, pp, and fw all release freely and properly well beyond any contact

as for the flywheel I'm using an southbend OEM single mass 20lb steel replacement.. I also have the OEM dual mass one, which has recessed bolt heads

they both behave exactly the same ruling out FW dimension issues and bolt contact

600whpA4

Have you checked to see if the clutch fork might be bent?

If the clutch releases while testing it on a bench then it should release while in the car if your pushing the fork in with a press. Only different factor between those 2 is the Fork. If the fork is slightly bent it wont allow the TB to be pushed in as far which means the fingers on the PP wont push in as far to release the disk.



You can always swap out the fork for another one or another option would be to put in some very thin spacers between the PP and flywheel which will remove some of the preload on the disk and release it quicker when the fingers are pushed in.

nts472

Nada, As I stated in my original post I changed the release arm (clutch fork). I just wish I had a clear view of whats going on inside of the bell housing.

nts472

I hit some progress. After repositioning my setup for a better view it turns out that my new release arm does release the clutch enough to produce a 0.5mm gap between the PP and the disk.

However it still grabs. I've narrowed it down to 3 things.

1. Unlikely, but disk contact with non rotation part (like the bolt contact idea).

2. Also unlikely, a dimension issue with the input shaft. Perhaps its bottoming out on the crank.

3. Possible, a dimensional issue with the release mechanism. (pivot ball issue?) While the outter edge releases, I don't know how much the inner region releases.

4. Not sure if this is possible, but over torque of the PP bolts? My torque wrench isn't the most accurate at 18 ft/lbs. While it was even could being slightly over tight be enough to clamp the disk more than normal

David.Norton

Sounds like the disk could be binding on the input shaft, and not floating off the flywheel. Are the 1.8t and 2.8 input shafts identical? I don't know, perhaps someone else here does.

600whpA4

Yes they are exactly the same and the disk doesn't really have to move to come free since the pressure plate is no longer forcing it against the flywheel.


nts472 - have you checked to make sure the pilot bearing is still in good condition since you installed it and the transmission?

I just got done test fitting a new clutch/flywheel for Clutch Masters with a special cut transmission I have. Had someone hold the pedal to the floor and I could not get the input shaft to spin even though the disk was free. Turns out the pilot bearing was damaged causing the input not to move at all.


You cant really over tq the pressure plate bolts since the cover is still going to bottom out on the flywheel.