C1Looking for Pressure Plate Diaphram style

[Clark Chapman]

I have a 58 C1 with the stock 283, flywheel and bellhousing. I am attempting to install a diaphram style pressure plate & clutch rather than the Borg & Beck three prong style and seem to have just about a 1" gap between the long neck through out bearing and the diaphram fingers. Meaning by the time the fork & bearing makes contact, the fork has no more travel. I have tried three different diaphram pressure plates including the 57-61 FI recommended PP and have not found the right one to work. Oddly enough, I have another 58 complete that has this same diaphram style pressure plate and short neck bearing and works fine. I'm gathering there must be a different year/application Chevy used a thicker diaphram Pressure plate????
Can anyone advise of the correct part number pressure plate or application it would have been used in to work in the 58?

[Loren L.]

Same throwout fork?? *NM*

[Clark Chapman]

Re: Same throwout fork??

Yes, Stock fork. I'm baffeled on this one.

[David N.]

Re Clutch/pressure plate

This sounds more like a through out bearing problem. There are two different lengths used in general. Try the thicker one from GM or aftermarket for comparison of size.

David Nims

[Clark Chapman]

Re: Re Clutch/pressure plate

I have what I believe is the longer coller on the through out bearing but still over 1" gap. I'll check with th elocal parts house to see if there is yet a longer coller.

[Roy B.]

Re: C1Looking for Pressure Plate Diaphram style

Your newer pressure plate, must be different then the old one or the fork is different if the bearing is the same .

[Clark Chapman]

Re: Re Clutch/pressure plate

I have what I believe is the longer coller on the through out bearing but still over 1" gap. I'll check with the local parts house to see if there is yet a longer coller. My ultimate hope was that someone could tell me if there was another application where a different pressure plate would have been used... say for example a later Chevelle with a thicker pressure plate that would suck up the gap I currently have. I noticed the fingers on the pressure plate that is in my finished 58 are angled outward toward the bearing whereas the one that has the 1" gap has the fingers flat.

[Roy B.]

Re: Re Clutch/pressure plate

As I said you have the newer type pressure plate they sell to day, look for the old design and you will be OK I think only two bearing are offered -short and long.

[Christopher R.]

Re: C1Looking for Pressure Plate Diaphram style

The 1" space between the pressure plate and the throw out bearing is taken out by adjusting the swivel on the clutch push rod. You've just got too much pedal free play adjusted into the linkage. See the ST-12 on how to take it out.

[Clark Chapman]

Re: C1Looking for Pressure Plate Diaphram style

I have tried the adjustable pivot stud as well. No luck. Still too far away.

[Clark Chapman]

Re: Re Clutch/pressure plate

Roy, The hole idea using the newer diaphram style pressure plate was to get away from the older three prong Borg & Beck chattery pressure plate design. Parts houses today offer the diaphram style as a direct replacement for teh fuel injected 58-61. I feel stupid saying this but my first 58 Vette has this new setup & it works great. I bought the car with it installed and as you know pressure plates don't have part numbers on them for me to identify it.

[John H.]

Re: C1Looking for Pressure Plate Diaphram style

Clark -

Must be a really "generic" pressure plate, with much lower fingers - are they flat, or bent rearward? (they should be bent). I've used the LuK "RepSet" replacement diaphragm clutch assembly from Paragon (with the correct 1-1/4"-long throwout bearing) on several C1's, and it was a straight drop-in with no linkage or geometry issues at all.

[Clark Chapman]

Re: C1Looking for Pressure Plate Diaphram style

Hi John,

The fingers are flat. If bent out towards the bearing I'd be ok.
Sounds like you have the best advise yet. I will check with Paragon to order one. Thanks!!!!!
Clark