VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Clutch chatter

Is there something different about the lining on clutch discs lately? I've had clutches installed in two vehicles recently, and both already have clutch chatter after only a few miles. A new clutch kit was installed in my 55 Bel Air about three weeks ago. A good used flywheel was installed, along with new pilot bushing and throwout bearing. The other car was an early 30s non-Chevrolet. A local shop rebuilt the clutch, resurfaced the flywheel, and installed new lining on the clutch disk. Both cars already have clutch chatter.
Sid

The number one cause of clutch chatter is soft or broken motor mounts. If you could chain or ratchet the engine down for a tryout it would tell you if thats the problem.

It is not common for a Chevrolet with an open drive shaft to have clutch chatter.
Other than the mounts it may be the replacement parts.
Did you have the chatter with the old clutch?

Yes. I did have clutch chatter with the old clutch. The flywheel surface was not flat, and the springs in the disk were loose.
Sid

I had a lot of clutch chatter when my rear seal leaked a lot. It is one thing to have a quarter sized leak than one the diameter of a coffee saucer!

Good luck, Mike

The mounts all look good. I'll try revving it up while watching the engine. If it is a mount it must be at the transmission. Thanks.
Sid

There is no trans. mount. If the mounts at the rear of the engine are broke (common on a 1955) it would have been found during the clutch repairs.

I just talked to my friend who did the clutch replacement. I'll take it to him in the next few days and see what he finds thanks. He thinks it may be the disk, even though it was new.

Replaced clutch and pressure plate with same brand. Chatter gone.
Sid

I spoke too soon. Drove it again yesterday and chatter is back. Must be something other than clutch itself.
Sid

Did the chatter get worse after some driving and the gear oil got warmed up? Try draining the present gear oil and going to 75W-140. Also make sure the rear spring U bolts are tight and rear spring front rubber bushing are good.

It did start chattering after warm up. I'll check those things and try the thicker gear oil. Thanks Gene,
Sid

If the "thicker" grease helps you will know the problem is in the transmission.

Thanks Gene.

Don't forget that excessive clearance on the engines thrust bearing will cause clutch chatter as well. That is why it is not a good idea to sit through a stoplight with the clutch pushed in. On many older engines the oil is quickly worn off the bearing thrust surface and then it is just metal on metal. Fortunately the babbit is rather slick but it will only last so long.