i have had this prob for a while I have a 69 camaro small block , i have replaced clutch and preasure plate and throw out bearing twice over the past 15 yrs. but always end up with a very tough pedal. it makes a binding noise and a crunching sound when you push it in and it gets worse as the car gets hot. i replaced the z bar or bell crank and both pivot balls on it this past fall ,still have this problem. i noticed that the ball in the bell housing for the clutch fork has a adjustment alllen wrench fitting in it , i have never adjusted this and it looked fine as far as the balls suface when replaced last clutch. i also have replaced clutch fork two clutches ago it also looked fine this past fall. im supposed to be in the 4th of july parade this year but its such a hassle with this clutch the way it is, not sure i want to do it. also seams to go away for awhile when i put a little oil on the clutch fork and ball but comes back after driving car in the hot weather. has anybody eles experienced this problrm? is there any type of lubricant that wont dissapate in the heat or worse yet end up on my clutch disc and flywheel ?

That internal hex on the rear face of the clutch fork ball stud isn't for adjustment - that's how you tighten it up, since it has a round head and is recessed in a spotface in the bellhousing. The factory used gray moly lube on the pivot face of the ball stud and the mating recess in the clutch fork (also used it on the throwout bearing groove and I.D.).

Is the throwout bearing installed correctly on the clutch fork with the ends of the flat tension spring in the groove with the fork? The design allows it to be assembled wrong, with the ends of the spring outside the groove.

Parade duty is the most severe abuse you can do to a throwout bearing. :(

I have the same problem, but not as severe as you do. My clutch fork is installed right, the pivot ball is new and lubed. I am thinking mine is a bad pressure plate, maybe warped or the bearing retainer on the tranny is bad and warps when hot. I changed the TO bearing to a metal one that gets greased from the plastic type. It helped some.

I went through years of grief with clutch chatter.
During the third R&R, I discovered that the bearing carrier on the tranny was groved from almost 40 yrs of abuse. Replaced carrier, used composite T/O bearing, now, smooth as silk.

I discovered that the bearing carrier on the tranny was groved from almost 40 yrs of abuse. Replaced carrier, used composite T/O bearing, now, smooth as silk.

Aside from misalignment in the linkage due to a possible incorrect part(s), I think that's a good possibility considering that pretty much everything else has been replaced (more than once).

Bearing retainer gets worn due to linkage misalignment as Dave suggests, but I would think after time, there would be a step worn in.

I would wager its the pressure plate spring pivot points having the wrong lube or no lube and the spring are creaking much like the screen door spring sweaking when opening or closing. Simuliar sound?