billt_57

I just recently replaced a worn out stock replacement clutch in my '91 305 z28. I put in a new Weber diaphragm unit,had the flywheel resurfaced, and installed a new throwout bearing. When I first started the car, the pedal feels pretty good, but I cannot engage the transmission into any gears without forcing the linkage. When I am in gear, the clutch engages very close to the floor. It does not feel like there is air in the clutch linkage, but I suppose it would'nt take much to cause this type of problem. Anyone with any experience in this area? Thanks in advance.
Regards,
Bill

TheGreatJ

Sounds like the clutch is dragging. Is the slave cylinder tight against the bellhousing? Check it and bleed the hydros just to see if it helps...failing that I'd say you have a weak seal in the hydros somewhere.

billt_57

I made sure that the slave cylinder is bolted tightly to the bellhousing, that the throwout bearing is properly installed, and I also used extra long bolts to locate the transmission on installation to make sure that the trans was not hanging from the clutch plate. The pilot bushing is new, and appeared to work smoothly when I lined the clutch plate up using the pilot tool. I also double checked that the throwout fork was seated on the pivot point in the right location. This pressure plate and clutch does hold with more pressure than the stock unit, and I have been told by the speed shop owner who sold me the clutch that the stock hydraulics may be leaking past the piston, or that the line might be bulging slightly due to the increased load. Does anyone know of a heavier duty hydraulic setup that will work?

TheGreatJ

The clutch hydros from an LT1 6-speed car will bolt right in, but the pressure line is longer so you'll have to do something about the slack. The line is also steel braided instead of the hard plastic that the T-5 hydros have. You can get the LT1 hydros new and pre-bled from GM for about $100.

Jim85IROC

I thought the LT1 T56 cars used a pull-type setup?

Anyway, let's look at this from a different angle. Air didn't magically appear in the lines while you were changing the clutch. If the hydraulics worked with the old clutch, they should work with this one. Unless somebody pushed in the clutch pedal while the slave was hanging, the hydraulic system should never have been disturbed.

I think your problem is somewhere else. You said you had the flywheel resurfaced. Unless they only took off a couple thousands, that could be your problem. The flywheels aren't supposed to be resurfaced, they're supposed to be replaced. I had mine resurfaced, but all it took was a couple thousands to get the crap off, and mine's working fine. Plus, the centerforce clutch requires an oversized throwout bearing that may have helped. But, others have not been so fortunate. I've seen a lot of guys have your problem because too much meat was taken off the flywheel. You may need to have it measured to see how far under it is, and put a shim between it and the crank.

billt_57

Jim85IROC,
I think your assesment is correct, due to the fact that the flywheel has been resurfaced twice. I have not mic'ed the thickness, but both times were minor cleanup cuts. I'm wondering if an adjustable pivot ball will do the trick.
Cheers,
Bill

TheGreatJ

The LT1 does use a pull-style clutch, but the only real difference in the hydraulics is the longer, steel braided pressure line which allows the slave to be mounted from the rear instead of from the front. That and there's no bleeder valve. The master cylinder is identical, and with the bleeder valve exception, so is the slave cylinder.