The Stovebolt Site Forums The Shop Area Engine Shop Rubbing noise. New Clutch, PP, etc. 51 GMC

51 GMC 1-ton with 302 straight 6.

I get a fairly loud scrapping noise just as the pressure plate is actually clamping the clutch plate to the flywheel, but not when the clutch is out or when fully depressed.

The 302 came with an oddball recessed flywheel which I replaced with a resurface 248 flywheel, and a new 248 pressure plate, release bearing and pilot bearing. I used the stock bell housing and SM420 tranny that had been mated to the stock 228.

The clutch seems to operate perfectly,no chatter or other problems, although seems to engage pretty high for a new clutch.

It almost sounds/feels like the clutch plate might be warped, thus does not engage smoothly, although when fully engaged there is no noise. The scrapping sometimes sounds metal to metal, not just clutch lining to metal.

Any ideas?

Clutch disc might be installed backwards. One side of most disc sticks out farther from centerline than the other. This usually causes a problem with clutch release.

JJ

I asked the mechanic who installed the clutch. He was certain in went in the right way, and I'm sure he's right since he's worked on so many old truck. I've put on a 100 miles or so and the noise seems to be decreasing. I guess I'll just live with it until something craters.

After installing mine, I had a lot of noise at first - almost like the clutch was trying to line itself up. I resurfaced the flywheel and put in a new pilot bushing and of course used a clutch installation shaft. The noise went not long after but I find that it grabs high as well.

You might be able to see something by pulling the cover underneath, but if I was to guess, it's a clearance problem between the flywheel bolts and the hub of the clutch disc. Did you use the flywheel bolts that were from the 248?