Clutch Master Help

Howdy! I have a caged and LS1 converted '87 944. I have the Spec Stage 2 clutch and flywheel with the modified OEM slave cylinder from TPC, Tilton pedal box and a remote bleeder setup from Speedway. I have tried both the 7/8" and 1" Wilwood Compact Remote master cylinders. With the 1" master, effort on the clutch pedal is high and exhausting over the course of a track day. But with the 7/8" master I cannot get clutch release and the transmission won't shift.

Perhaps I'm not getting a good bleed. But I've tried several methods: pressure bleeding with a Motive bleeder, pedal pumping with a SpeedBleeder bleed valve, and buddy bleeding like you'd do with brakes. I've tried jacking up the front of the car to bleed, and jacking the left side too. With the Tilton pedals, I'm certain that I'm getting a full sweep of the master, it bottoms out for sure. I've run a full quart of fresh fluid through this thing and the 7/8" master just won't release the clutch.

I read about vacuum bleeders but haven't tried it. I also read about manually operating the shift fork to bleed but don't see how to do that even with the C5 inspection cover removed. Other suggestions?

Thanks,
Rich

when you say modified oem slave, do you mean an oem corvette/camaro internal/concentric slave, or the oem 944 slave, and using a clutch fork?

with a factory pedal setup and the corvette slave most find a good pedal with either a 3/4 or 13/16 master cylinder. it is possible your not getting enough throw on the master cylinder, have you tried lengthening the pushrod for more throw?

Slave is OEM Vette/Camaro modified by TPC to fit their adapter plate. In the Tilton pedal box it's clear when you're getting the full plunge of the master cylinder. I'm sure but will experiment more.

And I agree it's odd I can't get good release with the 7/8" when others user smaller. When installed I did the measurements and it came out that I needed the spacer that Spec provides. It's in there.

Rich

edit: Ah, I see my 'manually operating the fork' comment caused your question. It was an S10 forum where they suggested that trick. So yeah, no fork and I don't see a way to compress our slaves manually without the hydraulics.

yea the part where you mentioned moving the fork had me puzzled.

if you can get under the release bearing with a pry bar you can push it back, this can help get air out. ive also put a vacuum on the reservoir and pumped the pedal and had good luck with that method.

when you say the 7/8" master wont release, will the car not even go into gear when its stopped, or is it just real hard to shift? there are other things that could be in play here that could be masked by going to a larger master, like the clutch disc being hung up on the input shaft, or the clutch disk hitting the flywheel bolts.

Thanks for your ideas, Sharkey. The clutch works and I've been driving the car for years with the 1" master. But it was a workout even when I was in good shape 5 years ago. These days...

Anyway, so I've swaped in a 7/8" master and am not getting clutch release. With the engine off I can move into all the gears, no problem. But when running, I can barely force it into 3rd and the car gently nudges forward. I can't get it into 1st or reverse at all, it grinds.

Today I tried again. I detached the master from the pedal box and inverted it while bleeding with the Speedbleeder. This with the car jacked up on the driver's side, tilted as much as possible. Buttoned it back up, started the engine and it's working. I'm getting release and can shift into 1st and reverse. Yay!

I will say that I got this far a few weeks ago with buddy bleeding. We got a decent bleed with release right at the end of the travel. Nice... But... a couple days later no release. So I've closed up the shop for today and will try to drive the car again in a couple days. Maybe now I'll go checkout a football game or something. I hear there's one on today...