Clutch Noise, Suggestions?

[Ken K.]

Clutch Noise - Diagnosis help needed!!

Here is the story: I removed the stock 283 engine along with the stock 3 speed transmission from my 1959 Corvette this winter to do some detailing and cleaning of the engine compartment. I then removed the tranny, clutch, and bell housing. Everything looked great. I then reinstalled everything back into the car this spring. Now I have a noise when the clutch pedal is pushed. It starts making noise as soon as the pedal is pushed and gets louder as it gets to the floor. It sounds like something is rubbing, a "Tinny" type sound. So.. I pulled the transmission back and removed the clutch pack and throw out bearing. The then got a NEW GM clutch pack assy. and throw out bearing and installed them. I bolted everything back together and tested. I still have the same noise!! Know what? Any suggestions? The first time I pulled apart the bell housing this winter, I noticed that the clip that holds the clutch fork to the pivot ball was broken. (one of the fingers was missing) So I removed the rivet that held the clip in place and installed a new clip onto the clutch fork. I'm not sure if this maybe part of my problem, but I thought I should mention it. Yes, I believe that the clutch fork and clip is correctly on the throw out bearing.

[Stuart F.]

Re: Clutch Noise, Suggestions?

As long as you are sure you have the clutch fork engaging the throw out bearing correctly, I personally can't think of what it could be if you only did what you indicate in your tear down. I have had many clutch related issues to deal with over the years having put Chevy V8's in other cars and jerry rigged linkages, but the only thing that comes to mind is clipping the spring clip of the throw out arm over the flange on the end of the bearing instead of letting ride in the groove. I made that mistake back in 1958 - it looked so natural, but I was wrong (back then we had little to go by instruction wise).

You've tried two throw out bearings so that rules out "no grease" or "bad bearing". Do you have a good bearing in the end of the crank for the transmission input shaft? Do you have the driven disc in right? (I'm not even sure if you can put it in backwards).

Hopefully others can come up with some suggestions. I'm sure this is one that even I will say; "Oh Ya!, why didn't I think of that?"

Stu Fox

[Rod K.]

Re: Clutch Noise, Suggestions?

May not be your problem but you can put the driven disc in backwards and the springs in the hub will rub on the flywheel-to-crank bolt heads. Could you do it twice? Maybe. Check your first clutch disc for scuff marks on the hub springs.

The clutch center hub is offset to one side of the disc (flywheel side is essentially flat, the pressure plate side will be raised). That side needs to be positioned away from the flywheel, should fit within the inner dia of the pressure plate and clear.

[Ken K.]

Re: Clutch Noise, Suggestions?

I'm almost sure I have the driven disc in the correct way. One of the sides had this stamped wording: "Flywheel Side".

[Stuart F.]

Re: Clutch Noise, Suggestions?

Ken:

If you find it is just a simple problem and you made a mistake, please post and let us know. We're all human and screw up once in awhile, specially as we get older. Either way, I'd love to hear what it is. Good luck.

Stu Fox

[Gary B.]

Re: Clutch Noise, Suggestions?

Have you put the car up on stands and looked in there while the engine is idling? You may see something while someone pushes the clutch. You say everything is fine until you start to push in the clutch. Something could be wrong with the pressure plate internally, you may have to try a different one since you have a new throw-out bearing. Of course does the disk look like the one you replaced? I believe that when you engage the clutch, the pressure plate releases such that the disk stays still and the pressure plate and flywheel continue to rotate. Assuming that you are in gear when you disengage the clutch and put you foot on the brake, then only the bearing, pressure plate and flywheel are moving. Theoretically, either something on the flywheel or something inside the pressure plate would be striking the disk or transmission input shaft housing or flying about internally. Just some thoughts to possibly help in your analysis of the problem.

[John H.]

Re: Clutch Noise, Suggestions?

Check the clearance (or lack thereof) between the flywheel inspection cover and the end of the flywheel-to-crank flange bolts; if you used ARP flywheel bolts, they're slightly longer than the stock bolts, and will make a REALLY "tinny" sound until you "modify" the contour of the cover.

[Chuck S.]

Re: Clutch Noise, Suggestions?

...I have a noise when the clutch pedal is pushed. It starts making noise as soon as the pedal is pushed and gets louder as it gets to the floor. It sounds like something is rubbing, a "Tinny" type sound...

If the clutch is properly adjusted, there should "free play" or travel in the clutch pedal that causes the throwout bearing to be moved into position, but the pressure plate diaphragm is not actually being depressed...Does the noise begin AFTER the pedal has moved through the free play and the diaphragm fingers are being depressed, or does it begin as soon your foot touches the pedal? Does the noise change as you move through the clutch pedal free play, or just start when you begin to feel the resistance of the pressure plate?

Because of the coincidence with the clutch operation, it sounds like a throw out bearing problem to me...maybe a misalignment of some type. Be sure you're following the pictures in the service manual for installing the TO bearing into the fork...it is not intuitive from looking at the parts. I believe that spring clip you replaced only keeps the fork in position until the tranny is installed and the clutch adjusted; once the clutch is adjusted, the springs in pedal mechanism and input shaft snout should keep the clutch fork positioned tightly on the pivot ball without the clip.