Well, after two weeks of doing nothing but trying to get my clutch system to bleed properly I broke down and took the car to a shop. They spent two days also trying to get it bleed properly. In the end they took the slave apart and put a spacer inside the slave to give it a bit more throw length. Apparently, when the rod is seated in the fork, there was about 1/4" of distance between the clutch housing and the slave unit. So now I am only getting about 1/2" of movement total. My fork seems to be pretty far into the housing.

The car seemed to drive and shift pretty good thru out the day when I picked it up, but as the temperature dropped so did my shifting. This morning I am back to square one with considerable difficulty in getting a smooth shift.

I now think there is something wrong with either the clutch fork, ball stud or release bearing. I have never done anything with clutches before and I am wonder just how much work I am looking at in getting the trans out and inspecting the clutch release parts. Any ideas???

I also had the shop drain and fill the trans with fresh GM fluid and he replaced the plugs for me since mine were starting to strip. That's all they charged me for too.

 

I know you started a similar thread, and I can't remember if you stated if you had anything other than stock clutch components...do you? If not, there's not much magic to getting this thing right. The ball and rod do not go bad unless you have other major problems which I doubt you do. If someone replaced the clutch and/or flywheel, therein could ly your problem. The thickness of the FW and overall stack height of the whole assembly is critical. .100" makes a huge difference in the clutch operation. (Don't ask me how I know)

 

Hey Aaron, can you get under there and look at the motion of the clutch fork, while someone pushes the pedal for you? You should be able to see if there is slop in the pivot. If the pivot moves back at it's pivot point than that's your problem.

I also had clutches come apart, and a piece of lining get between the disc and the pressure plate, this makes the clutch engage.

I would rule out the slop in the pivot before persuing this, as the clutch will have to come out to check for broken lining.

Good Luck! :smash:

 

It sounds like you have a similar problem to mine. My clutch seems to work fine, but makes some strange noises.

I jacked it up and played with the linkage, and I could push the damn fork into the clutch housing about 1/2 an inch. Not good. There was also lots of play in the direction of the pushrod. I'm guessing my pivot is broken/loose.

I haven't fixed it yet, the vette is up on blocks and I'm gonna replace the whole clutch and check it out. I've never done a clutch before either, but if I get it done in the next week or so, I'll let you know what I find out.

 

I think you made a post about this before and I asked if you had the flywheel surfaced or replaced?? Alot of aftermarket flywheels are not as thick as stock and can cause problems with disengaging of the driven disk. I'm pretty sure the stock dimension for the flywheel is around .950". The Hayes steel flywheel I put in my 85 was only around .850" and the clutch would not disengage at all and the fork was kind of sloppy due to this difference in thickness. Using a shim and fabbing up a new pivot ball to take up the .100" diff. made everything work as it should. You have to compensate for this with either a shim between the flywheel and crankshaft or increasing the length of the pivot ball which moves the throw-out bearing closer the the press plate allowing proper disengagement of the disk.

If the clutch has not had any components replaced, it kink of sounds to me like the press plate fingers may be worn which prevents them from taking up the slack between the fork and push rod. In a hydraulic clutch set-up the throwout bearing only moves back as far as the press plate will push it, if the fingers are worn, broken, or otherwise damaged there may be a gap too large for the hydraulic system to make up for. This would explain the gap between the fork and pushrod and also explain why your clutch is not releasing properly.

Hey Central Coaster, I had this prob also and the fork had just hopped off of the pivot ball. Pop the rubber boot off of the tranny where the pushrod meets the fork and look inside the tranny. It is kind of a pain, but I was able to get mine back on with a long straight screwdriver.

I had never done a clutch before either, but it isn't that bad with all of the help you get here. Just finished mine a couple weeks ago on my 85 so if I can be of any help let me know.

Good luck guys.

Sturtzy

 

Cool, thanks for the offer.

How the hell did you get it back on the pivot ball? I really have no idea what it looks like, so I can't do it blindly.

The clutch was working fine though, but I parked it anyways. I think it's just a loose pivot, and like you said, a worn pressure plate (broken or bent fingers?) If I could temporarily fix the pivot without pulling the whole damn car apart, then I could get some miles out of it.

Is there a nut that tightens up on there or a clip or something? I'm guessing mine stays in place while driving, but the slack just allows everything to make noise.

If the pivot is bad, a good pressure plate might not even be able to push it back all the way to take up the slack. The push rod is wayyy loose with the clutch disengaged. I can move it about 3/8" back and forth. The pressure plate should always keep this snug correct?

 

There are two small spring loaded fingers on the fork that attach it to the pivot ball. If one of them jumps off of the pivot ball the entire set up becomes very sloppy and can cause the clunking noise you spoke of earlier. Mine still released fine, but there was a clunking noise and a slight hitch in the pedal when trying to disengage the clutch.

I removed the rubber cover on the pushrod which allows you to see inside the tranny. I was able to get a screw driver on the little finger on the fork and manouver it back over the ball. I would say the chances of the pivot ball coming loose are very slim as the trans stops it from backing out of the bellhousing.

Assuming you have a good press plate, the fingers should push the throwout bearing back when the clutch is engaged and there should be no slack in the pushrod, fork area of the linkage. If the pivot ball is broken or the fork has detatched itself somehow the press plate should prob still have enough force to push the throwout bearing back. My guess is a worn press plate or air in the system not allowing full travel of the pushrod. I'm not sure, but even with a worn press plate the slave cylinder and pushrod should be able to take up the slack and move the bearing up to the fingers. This is why hydraulic clutches are considered to be non-adjustable. As the clutch wears, the hydraulic system adjusts itself to compensate.

What year vette and type of tranny? I guess I should have asked this sooner. Alot of ramling on, but I hope it helps.

Sturtzy

 

As far as I know, the original clutch parts are still on the car, as well as the original flywheel. It's a 91 ZF trans. I only have service records for the past 3 years on the car. Not sure what exactly was done before that. The car has 29K miles on it right now.

Keep the info comming. How hard of a job is it to drop the trans and pull the clutch assembly to inspect them?

 

I've got an 85 with the 4+3 in it, same as you sturtzy. I couldn't see anything through the bell housing to work with, but I'll see what I can do tomorrow. I just got my main seals changed and the pan back up, but I'll see if I can see anything through the inspection cover.

Aaron, I'm not exactly sure on your exact setup, but you'll have to drop the entire exhaust and support the motor somehow before removing the torque beam. I haven't taken this out yet, but I've heard varying stories on how doable it is. It might be easier for you, since I think the ZF's have a larger tranny tunnel. There's some good posts in the archives about it, "torque beam" or "C-beam" its usually called. Make sure however you support the car that the rear wheels are free so you can spin them in order to access all the driveshaft bolts.

 

CentralCoaster
.4+3 clutch fork is easy.Just pull it back out of the bellhousing while holding it towards the rear of the housing The spring clip attached to the fork slides back on the pivot unless the pivot is broken.Stupid arrangement allows the fork to dislodge as the cylinder pushes on it .
Has happened to me several times.