Clutch adj. problem... - Pontiac GTO Forum
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post #1 of 5 (permalink) Old 06-16-2006, 10:05 PM Thread Starter
 
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Clutch adj. problem...

I have a 1968 GTO that is a orginal 4/spd car that I up graded to a Tremec TKO 600RR. I removed all of the orginal bellhousing and replaced it with a Mcloed scatter shield, flywheel, 12" Kevlar disk, clutch fork and release bearing. This was a kit I bought from Classic Five Speed Chevy and all went well untill I tryed to adj. the free play. There is no way that I can seem to get enough travel out of the pedal to give me the called for .050 of air gap to the flywheel. I have tried adjusting the length of the pivit ball and using the Mcloed adj. release bearing and all of this did not produce the travel at the clutch fork that I need. I also removed the rubber bumper from above the clutch pedal as well as bending the tab that it set in out of the way for additional pedal travel. All of this together gave me .049 of air gap but only about 1/2 of free play. This car orginally had a 11" GM clutch setup and I never had a adjustment issue. My stock 67 Chevelle has aprox. 1 1/4" of travel at the release arm but with all that I have done I only have 1 1/8 in the GTO. Has anyone ran into a problem with this before or could I have missed something in the setup...

Thanks: Rock

Last edited by Rock; 06-16-2006 at 10:16 PM.
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post #2 of 5 (permalink) Old 06-16-2006, 10:32 PM
 
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I don't know about your particular setup but I did a bunch of clutch changes in my '67 Firebird years ago before I finally settled on a Centerforce to hold all the power.

Anyway once I put a clutch in (diaphragm type, don't remember the brand) and it would not disengage just like you are describing, and it drove me nuts because I was sure I had done something wrong but couldn't figure it out. I actually managed to find the factory phone number and called them up. I ended up talking to the shop manager who told me to pull the pressure plate off and take some measurements for him. It turns out the pressure plate was not set up properly at the factory. He was pretty PO'd about it getting out that way, he had me return it directly to him and he sent me a new one via express. The new one worked perfectly.

Its something to think about. There was absolutely no way to tell there was a problem with the pressure plate just by looking at it.

06 Impulse blue, M6, 17"
69 LeMans vert, stock-looking 455-powered "sleeper"
74 455 TA, HPP magazine cover car
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post #3 of 5 (permalink) Old 06-17-2006, 10:58 AM Thread Starter
 
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Yes, I thought of that and did contact Mcloed tech for all of the spec. and removed the disk and measured as they suggested and all points checked out. I don't think the clutch is the problem except that it seems to require more air gap that some other clutches. I suspect that my problem lies with something in the clutch actuation linkage itself, but I have been wrong before. I say this because of the lack of travel that the release arm has compared to my 67 Chevelle linkage. By taking all of the steps that I have mentioned in my org. post plus the one thing I forgot to mention is that I modified the bell crank lever by cutting one inch out of the arm, I can still not make as much travel as the Chevelle. Thanks again.
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post #4 of 5 (permalink) Old 06-17-2006, 11:40 AM
 
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Well then it sounds like a geometry problem caused by one or more of the new parts just not matching up.

I am not sure what you are referring to by the "bell crank lever" but you can always modify the clutch arm to give you more throw. (I assume that this is the same as on the F-body, with a pivot tube that rides between the engine and the frame.) I've done this before to get header clearance and still have adequate throw. The shorter you make the arm on the pedal side, and the longer the arm on the push rod side, then the more throw that you will get. Just cut off an arm and weld on a new one with the length that you want. Make sure that the weld is good and strong!

06 Impulse blue, M6, 17"
69 LeMans vert, stock-looking 455-powered "sleeper"
74 455 TA, HPP magazine cover car
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post #5 of 5 (permalink) Old 06-17-2006, 12:49 PM Thread Starter
 
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Yes, you are correct about decreasing the length of the arm on the clutch pedal end of the bellcrank and the swivel ass. should gain motion at the release arm, but after removing 1 inch from the arm I still gained only 1/8 of motion at the realease arm. The 68-72 A body cars have what is called a Bellcrank and Swivel Assy. that replaces the Z- bar that is used in all other Pontiacs. It has one side called the Swivel Assy. that bolts to the side of the block and the bellcrank end that bolts to the frame side and in the middle of this is a swivel coupler that connects the two halves togeather. I rebuilt both sides of this assy and it seems tight enough but yet I can't figure out where the loss in motion is comming from. Thanks for the effort... Rock
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