I'm working on a 98Z with a T56, and the Star Stage 3 clutch . It has the new Star steel flywheel, new slave cylinder (GM) and the original master cylinder (not ideal, I know, but it should at least be driveable til the customer can replace it with the new style one). I have thoroughly bled the clutch, and am confident there is no air left in the system. The clutch pedal feels normal.
When the car is started in neutral, it won't go into any gear. If you place the car in any gear while starting and holding the clutch, it will move , indicating that for some reason the clutch isn't disengaging. The throwout bearing is moving, but not enough apparently. I have talked to two different Star clutch dealers, both of whom install them regularly, and both say that there is supposed to be a shim with the kit that goes between the front of the trans and the slave assembly. It wasn't in the box (clutch was supplied by the customer, who bought from an individual) . The customer seems to think there is air in the system, but I know that isn't the case. If there was any air in the system, it has been bled out. Has anyone here had a similar problem with this clutch not disengaging, and what had to be done to fix it? I know thats the problem, but my customer still needs some convincing.

 

I had the same problem, the pivot ball needed adjusting. Is yours adjustable?

 

There's no fork or pivot ball on the LS1 style, just a hydraulic slave cylinder/throwout bearing assembly that bolts to the front of the trans. The fact that the clutch has been bled and rebled, and shows no sign of air in the system, leads me to believe that at the very least, the shim is needed to give the throwout bearing a little extra travel. If it still doesn't work, either the stock clutch MC isn't delivering enough fluid, or theres some problem with the clutch itself. I'm hoping that just adding the shim will do the trick.

 

Dont Spec clutches for LS1 t-56's use a shim?

 

The Spec Stage 3 clutch does have a shim. It some kinda paper/fiber and is about 1/8" thick. The instructions say you need the shim.

The slave cylinder in the 98-00 Cars is weaker than the later ones. It is highly suggested that you upgrade to a 01+ slave. Do some searches on LS1tech.com for some info about this.

 

Even with the shim , the new slave, and the new master its still doing the same thing. I called SPEC, and they're going to issue an RA. Its not too common, but apparently there is a defect of some sort. I have done about 20 clutches between LT1 and LS1 cars, and only had a similar problem once...it was the clutch/pressure plate in that case. It was on my SS (LT1), and since LT1 hydraulics don't even have to be disconnected and a different clutch solved the problem, I know it wasn't a hydraulic problem then either. Ah, the joys of working on other people's cars...