Got the 383 motor running and it sounds great. Tried to shift car into gear-no way unless the engine isn't running. I replaced the Clutch master, slave, and hose while the engine was out. Have tried every recommended procedure for bleeding the clutch system (including all past threads here) with no luck. Basically, the pedal has little resistance for first 3/4 of travel, then you can feel the pressure plate spring pressure. Started it up in gear and drove around for a few blocks, but clutch definitely is not fully disengaging. This clutch was in use before the engine change since it only had 500 miles on it. I replaced the hydraulic components as preventative maintenance while overhauling the engine. After 3 days of frustration, I admitted defeat and took it to the local corvette garage here. They tried bleeding it with no luck, but the fluid started to darken up. They told me of a similiar problem with a new and faulty Raybestos master cylinder. After installing a new Wagner unit, the problem still exists. Clutch fork, pivot ball, and pushrod all look good. Watching the slave cylinder movement as you press the clutch pedal, it appears the piston is not traveling all the way down the bore, leading us to believe the system still has air trapped somewhere. Total travel measured at the shift fork is about 1 inch. The shop is going to try replacing the new slave cylinder just for grins and bleeding the system yet again. Sorry for the long post, but the collective "we" are running out of ideas. I know from lots of experience that bleeding clutch systems is a real pain, but I'm "stumped". Any experienced answers out there? :cry

 

We're going to need to year your car is.

Are you sure you installed the clutch release (throwout) bearing correctly? It's an easy thing to screw up. I can't remember which way the clutch release fork spring faces now (it's been a while), but when you're putting a new release bearing on it looks you should install the bearing with the flange between the spring and the fork but this is not the case. Anyway if you mess this part up the release bearing is effectively too short and you'll never fully disengage the clutch. The clutch fork will still move the correct distance but the release bearing isn't contacting the diaphragm until it is well into it's travel. This explains how 3/4 of the travel feels unhindered by spring pressure.

Have you considered this possibility?

EDIT: Actually with a 4+3 trans, if you installed the bearing incorrectly you'd never be able to fully ENGAGE the clutch. This is the reverse of what I said the first time. The clutch would always be slipping. To have the problem I described you'd have to have the release bearing in backwards on the fork.

Anyway it still sounds to me like the release bearing has been installed improperly. Do you have a ZF 6 speed?



[Modified by jmr302, 3:58 PM 3/15/2002]

 

It's an 87 with the 4+3. Throwout bearing is properly locked to the fork. The sleeve on the beaing has a collar that enages the 'fingers' on the fork. The spring you are talking about is on the back of the fork furthest from the clutch. It simply puts tension on the lip of the collar so the bearing doesn't fall off the fork. Any other ideas, anyone?

 

Oh, I feel sooo stupid. Third time the clutch has been out of the car since my son bought it. First time I got the bearing collar screwed up even though I THOUGHT I checked it twice. You are absolutely right. If the bearing collar goes under the spring, the collar will bear against the spring and stretch the spring before it pushes against the diaphram fingers. Oh well, at least I only have to slide the transmission out of the bellhousing far enough to unclip and reinstall the bearing. Thanks for a fresh set of eyes on the project. Sometimes you can't see the forest for the trees...

P.S. I rebuilt the 4-speed and the overdrive. No more gear noise in reverse (bad gears and a bushing), no more jumping out of second gear (new locking synchronizer and slider assembly), and the overdrive has a nice, firm engagement like an automatic with a shift kit! Brian at S-K Speed was a big help with parts and rebuild info. I did have to add to my tool collection with a dial indicator and vernier calipers, as well as a homemade spring compressor for the clutch apply piston in the overdrive.

 

The correct way to bleed the clutch hydraulics on these cars is to have the slave cylinder unbolted from the bellhousing; dangling with the bleed valve positioned so its the uppermost part of the assembly. This allows trapped air to escape when bleeding.

 

After installing a new master/slave for my 87 clutch, we bled that thing purple and it remained spongy. On the fourth morning to go to work, the clutch was firm and has been ever since. I'm guessing air stuck in the master cylinder that finally found the exit sign.

 

Two years ago I did a engine switch and the slave cylinder was hanging for several months it was not apart no way for it to get air but when I got the engine back in the clutch would not release but after pumping the clutch about 50 times it started working fine. I don't know why but thats what happened so try pumping it several times see if it gets better yes it sounds crazy but it worked. :crazy: :smash:

 

I'm having the same problem right now. Last summer it also happend but it was the TO bearing falling apart last year. This year the TO bearing fine but I did find out that the ball the fork rides on was bad replaced that thinking that was the problem but I still have the same thing I know that the bearing is in right.
I'm glad you found out what your problem was I-FLY-AF but thats not mine any help would be great thanks.
:flag

Dave