Clutch linkage adjustment

[Steve D.]

63 convertible

New clutch (Centerforce), nuts and swivel are at the END of the rod, no useable threads left. Free pedal travel at the TOP is 3/8 inch. I read in the archives that it is supposed to be 1-1/4 inches. What next, a longer linkage rod?

Steve

[Joe L.]

Re: Clutch linkage adjustment

63 convertible

New clutch (Centerforce), nuts and swivel are at the END of the rod, no useable threads left. Free pedal travel at the TOP is 3/8 inch. I read in the archives that it is supposed to be 1-1/4 inches. What next, a longer linkage rod?

Steve

Steve------


Assuming that a longer pedal rod was a solution, I don't know where you would get such a longer rod that would otherwise be configured for the application.

[Steve D.]

Re: Clutch linkage adjustment

Joe

That very thought was on my mind as I typed the post. The clutch operates fine: no problem engaging or disengaging, no slip, no chatter. Is the main concern excessive wear on the TO bearing?

[Joe L.]

Re: Clutch linkage adjustment

Joe

That very thought was on my mind as I typed the post. The clutch operates fine: no problem engaging or disengaging, no slip, no chatter. Is the main concern excessive wear on the TO bearing?

Steve-----


Insufficient pedal free play can cause clutch release bearing problems or clutch wear problems. However, as long as you have "some" free play, you should be ok. I have found that when one achieves the free play specified in the service manual, then one usually has a problem with incomplete clutch disengagement at full pedal deflection. This causes hard shifting and gear grinding.

[Timothy B.]

Re: Clutch linkage adjustment

Steve,

If you read in the 1963 AIM there is another adjustment procedure. The book states to loosen the two adjusting nuts and I think 1/8" space after pushing up on the linkage and pulling down on the bellcrank.

If you do this there probably will not be 1" free play, just make sure the return springs are in working order. I am not exact on the procedure it's been a while since I read this.

[Steve D.]

Re: Clutch linkage adjustment

Tim

I'm looking at Section 7 Sheet C2.00 of the AIM. It says

.... apply 5 pounds load to the rod to eliminate clearance between throwout bearing and clutch fingers. Run upper nut towards swivel until dimension is .130 - .180 inch. Tighten lower nut to lock against swivel.

I guess the trick is in knowing when you've got the face of the bearing off of the fingers?

Steve

[Joe C.]

Re: Clutch linkage adjustment

Free play for 1963 was originally 3/4". It was increased to 1 1/4" starting in 1965. That free play assumes that your clutch is in "standard" position. If it is in "quick release" then free play should be proportionally less.

If you put your index finger on the clutch pedal and lightly press down, it should travel the "free play" amount, and then you'll feel resistance. That's all there is to it.

[Bob R.]

Re: Clutch linkage adjustment

I had a similar problem and found that the 66 / 67 rod is 1" longer. The part cost about $20.00 problem solved.

[Joe L.]

Re: Clutch linkage adjustment

I had a similar problem and found that the 66 / 67 rod is 1" longer. The part cost about $20.00 problem solved.

Bob------


Yes, the 66-67 rod is 1-3/16" longer. However, I thought there was a slight difference in configuration of the rod. However, I see that the 66-67 rod, GM #3888213, replaced the 63-65 rod for SERVICE. So, that means that GM considers the 66-67 rod an acceptable replacement.

[Tim S.]

Re: Clutch linkage adjustment

I had the same problem with a Centerforce clutch I used a few years ago in a 67 427 car. Just needed a longer rod. The clutch was defintely a raised diaphram and would only use a short bearing. I suppose it is just a Centerforce issue.

Tim

[John H.]

Re: Clutch linkage adjustment

The clutch was defintely a raised diaphram and would only use a short bearing. I suppose it is just a Centerforce issue.

Tim

Tim -

All Corvette diaphragm clutches had bent fingers and used the "short" (1-1/4") throwout bearing; the "long" bearing (1-7/8") was used on passenger cars and trucks that used the "flat-finger" diaphragm clutch.