[north]

My 69 GTO with its bone stock M-20 has a rattle type noise whenever the clutch is released. Makes no difference if it’s in neutral or in gear while driving. If I push the clutch slightly (less than an inch) it goes away.

Problem developed about 6-7 years (probably only sub 1,000 easy cruising miles) after I changed out the clutch (Hays stock style clutch-cleaned up original flywheel etc). I pulled the trans at that time and replaced the throw out bearing and inspected the clutch and pilot bearing.

This did the trick but within a few months (maybe 200 easy going miles) the noise came back. In July of this year I again replaced the throw out bearing and again I inspected the other components and everything looks perfect. Linkage is all nice tight and lubed. Fork is a NOS GM from about 10 years ago.

It is barely noticeable when started cold but by the time you’re at operating temp it’s there clearly.

Clutch action feels perfect, no vibrations etc. Inside the car it’s a light almost bell like sound but if you stick your head under the car it’s clearly a rattle and clearly from the bellhousing area.

Anyone have any thoughts or similar experiences? I’ve owned the car for almost 30 years. Never happened before and it developed years after I had replaced the clutch so it wasn’t something that happened immediately after I had been in there.

[dataway]

I'm curious about this because my tractor has the exact same symptoms .... also still there AFTER I replaced the throw out bearing.

[68ragtop]

Does the sound stop as soon as the T.O. bearing is pushing on the plate fingers, or does it need to be pressed in to where the clutch is disengaged to stop?

[north]

It takes just a light touch on the pedal to stop the noise, just taking up the lash. If you drive with your foot gently applying a bit of pressure on the pedal it goes silent.

It’s not the pedal itself making the noise, pulling on the pedal with my hand doesn’t stop the noise.

[68ragtop]

Pulling the pedal up should completely take the T.O. bearing out of the equation as long as it is sliding back like it should be. So unless the bearing, fork, or pivot ball is rattling from vibration, it would seem its likely coming from the pressure plate. Is it a diaphragm type, or 3 finger?
just my guessing from the living room couch of course......

[Simple Man]

Linkage rattling?

[Held for Ransom]

Almost sounds like the clutch disc. Either the marcel or springs.

[north]

All the external linkage is tight and properly lubed. The return and anti rattle (hmmm) springs are original and nice and snug.

Noise only starts after car is fully warmed up.

I think I’m going to change out the pressure plate and disc.

[428goat]

Why don’t you try putting in two new springs. The one from the fork to the z bar and then return spring. Maybe they are just tired.

[north]

They feel nice and tight but I’ll try it. 5 min test. I just hate to unnecessarily replace factory parts with Chinese repro junk.

[68ragtop]

Originally Posted by north

They feel nice and tight but I’ll try it. 5 min test. I just hate to unnecessarily replace factory parts with Chinese repro junk.

And almost everything is nowadays

I wouldn't think it would be the disk springs because you said it went away as soon al you put even a little bit of pressure on the pedal So really only the Pressure plate springs are changing at that point & the disk is still spinning the same & tight. The heat change is interesting.....

But, if its one or the other, your obviously not going to just replace the plate so I guess its a moot point if its one of the two.

[Held for Ransom]

The clamping force transfers the sound to a larger surface area and dampens it. I'm still leaning to that's the problem.

[george kujanski]

Does the clutch fork fit snugly on the t.o. Bearing?

George

[68ragtop]

One too many WOT side steps

[north]

The fork was nice and snug with both the bearing and the ball stud. No looseness.

[north]

I'm going to buy a clutch-pressure plate kit. Any recommendations? I like a firm feeling clutch but not too stiff. Just street driving and I'm easy on cars but don't want a clutch that slips. Engine is a stock 428 HO, 3.23 gears and 4,000 lbs of car to move.

[coonhunter70]

Look at the piece that the throwout bearing rides on, they wear with age also. I'm brain dead at the moment cant think of the name of it,

[north]

Do you mean the input shaft or the tabs that hold the bearing against the fork?

[68ragtop]

I think he's talking about the part that holds the 1st main tranny bearing in place.
Held in by (4) 5/16 bolts as I recall. The T.O. bearing slides on it. I believe he's thinking maybe theres a chance the T.O. bearing is loose on that shaft and rattling until it touches the P.Plate fingers.

[coonhunter70]

Originally Posted by 68ragtop

I think he's talking about the part that holds the 1st main tranny bearing in place.
Held in by (4) 5/16 bolts as I recall. The T.O. bearing slides on it. I believe he's thinking maybe theres a chance the T.O. bearing is loose on that shaft and rattling until it touches the P.Plate fingers.

Yep that's what I was thinking