clutch noise ?

[G Winter]

After many years I finally went out and purchased a corvette. I found a
1990 convettible with the 6 speed. Often but not always , usually when the
car is good and warmed up I get a clatter which seems to come from the
bellhousing area. Most of the time when I press the clutch pedal it either goes
away or decreases. I don't have to release the clutch to make the change in sound. I have no idea what kind of clutch setup these cars have. Is it a hydraulic throwout bearing ? any ideas on this noise would be apreciated .
Another little noise is a kind of groan when I first move the car. about 15 seconds after starting the car. Is this the antilock system testing ?
The engine also seems to have an uneven idle. Not always the same. Some
days very smooth other days rough almost to the point of a miss. I have replaced the plugs and plug wires and the dist. cap and rotor look good. Any
ideas on this ? thank you

 

[jmccloud]

Clutch clatter and start-up groan

Welcome to CAC. Lots of good company.

Sounds like the throw-out bearing. The actuator is hydraulic, the throw-out bearing is conventional and will make noise as it ages, gets dry, wears out, etc.

I have a Camaro that had a noisy throw-out bearing for several years. Clutch disk finally went so I replaced everything. Sometimes they last a while even though noisy, sometimes they go quickly.

PITA to replace, do the disk and pressure plate at the same time. And don't forget the pilot bearing.

The groan is likely the anti-lock setting itself. My son, father and I have had 8 GM cars with anti-lock brakes, 6 of which groan noticably much as you describe. Two of them are quiet. Sounds like yours is typical.

A quick test of the anti-lock is to jam on the brakes while on gravel (I use wet grass on the field next door) to make sure they actuate (pulsing brake pedal and a groan from the wheel that's working with just a short skid mark - or none).

Hope this helps

 

[G Winter]

really helpfull.

jmccloud
Thanks for the info, I can rest just a little easier now. Planning on about a 400 mile road trip in a few weeks, was a little uneasy obout the noises.I had visions of input bearing in tranny or a diff. going out on me. Now all I have to do is figure out the rough running.
Thanks a bunch.

 

[rrubel]

Some aftermarket throwout bearings (like the Centerforce) are just noisy by design. They're solid, work great, and their only downside is noise.
[RICHR]