clutch issue

[TBART70]

I just changed over from a hydraulic to manual clutch in 71 Chevelle. 454 with a TKO 600. It's my buddies car, he complained about it having bad pedal feel so we went with mechanical. It still grabs low off the floor and I have to adjust it all the way because I couldn't get it into gear. But I'm afraid the throwout bearing is riding on the clutch too much. The clutch has 3000 miles on it.

any ideas?

[parsonsj]

Where's the clutch doctor? Andrew Borodin, paging Andrew Borodin!

jp

[TBART70]

help

[TBART70]

I extended the lower lever about an inch and it made it much better, and then something went wrong, the bracket on the frame tweaked and I lost my throw. I moved it back and welded it on.

should the clutch grab off the floor or higher up in the travel?

[parsonsj]

A properly adjusted clutch should grab a couple of inches off the floor. The normal "grab-zone" (a newly invented technical word ) should be about two inches from the top, and two inches from the bottom.

Hope that helps.

jp

[67ragtp]

Tbart70,

check the fork angle, more often than not it is misadjusted. The end of your clutch fork at the adjuster rod should be 5 to 7 degrees forward(towards the engine) while the throw out bearing is resting on the fingers of the pressure plate. This typically requires the use of an adjustable pivot ball. An inncorrect angle can really put you on the edge of not being able to fully disengage, then your over compensating by moving the throw out bearing closer to the fingers to try and gain a little more throw, before you know it your bearing is riding on those fingers and you have no free play. hope this helps.

Rich

[TBART70]

I think the problem lies in the ball stud and the fork. I just learned that there are a couple of clutch forks. The one I used supposedly came right from a BBC Chevelle. I think it may be the wrong one, it would explain a lot. I went to a car show today and the general consensus is there is not enough throw in it. It is either the wrong fork or for some reason I have to get the longer ball stud. Anybody know what the factory part # is, or picture or measurement of it?

[4 speed]

The correct fork is 3892632 It is still available from GM. The link has pictures and a measurement to compare to what you have. Some times you need am adjustable ball stud to compensate for the difference between factory pressure plates and aftermarket ones.
Russ

[TBART70]

The correct fork is 3892632 It is still available from GM. The link has pictures and a measurement to compare to what you have. Some times you need am adjustable ball stud to compensate for the difference between factory pressure plates and aftermarket ones.
Russ

Thanks for the info. I saw the part number on your site and ordered it. It is the same one I have. Do you think the longer GM ball stud ( I have already ) would work. Could it be the throwout bearing height?

When I converted this thing back from hydraulic, I called Keisler ( who supplied the whole kit ) and asked for the bearing that went with the clutch kit they supplied. I have another Keisler bell housing, what is the measurement from the ball to..... what. I put my spare short ball stud in it and measured. It is 4.75 from ball to block mounting flange.

thanks for the help

[andrewb70]

I think the problem lies in the ball stud and the fork. I just learned that there are a couple of clutch forks. The one I used supposedly came right from a BBC Chevelle. I think it may be the wrong one, it would explain a lot. I went to a car show today and the general consensus is there is not enough throw in it. It is either the wrong fork or for some reason I have to get the longer ball stud. Anybody know what the factory part # is, or picture or measurement of it?

You're on the right track there. Sorry about the delay. I just saw the thread.

Honestly, you should have stuck with the hydraulic. Too late now..LOL Keep us posted on how it goes.

Andrew

[TBART70]

I should have messed around with the hydraulic,but my buddy wanted it changed. I did do one thing, I moved the lower arm of the Z-bar because it was going to interfere with the header, I'm wondering if it is off a little. Maybe the throw is off. Could it be in the pedal, how much difference do you think if the hole was in the wrong place on the pedal?

[TBART70]

I finally got around to pulling the trans, I put in the longer GM ball stud and it pins the bearing to the clutch, I compared a stock bell and the Keisler in this car to another Keisler in a different car. The recess for the ball stud in the Keisler is deeper than the stock bell , the other Keisler I have for another car is the same as stock. They make the bell thicker and have to recess it I think. I don't think it is in the ball stud area, I think it might be in the pedal or z-bar area, both are aftermarket. The throw out bearings look to be the same height. I am at a loss at this point. Any ideas? Could it have too much angle? Could it be in the pedal, how much difference do you think if the hole was in the wrong place on the pedal?

[garys 68]

Good read on clutch geometry for correct stud placement and throwout bearing length.
http://www.novak-adapt.com/knowledge/clutches_etc.htm

[TBART70]

good info I going over it with a fine tooth comb.

thanks, I think this will help. I think we are looking at small increments that add up all the way through the linkage and cause a problem.

[TBART70]

Installed the long ball stud with a shim because it was too long, essentially making it adjustable, set to the specified distance for throwout to fingers, it is better, I think there is and issue with the aftermarket pedals, the clutch pedal doesn't come up far enough. I have to mess with the z-bar again and modify the pedals and the it should be good.

[TBART70]

Long ball stud and modified z-bar worked, now it grabs where it should and there is adjustment to spare. Modified the pedal also, where the pedal stop is the metal surrounding the area was not like a stock one. (my buddy has a factory car I looked at). I had to remove some metal so the pedal would come all the way up. Now it works.

thanks for the help

[andrewb70]

Glad you got it working properly!

Andrew