pivot ball adjustment, info needed!

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pivot ball adjustment, info needed!

Postby 73astregt » Sun Mar 29, 2009 1:01 pm

hey guys does anyone have the proceedure for adjusting the h body pivot ball? i have the scan that peterpan posted for the cable adjustment but ill need to adjust the pivot ball as it had been removed from the bellhousing for painting by the last owner of the bell and not reinstalled to its former setting. thanks for your help once again!
73 astre gt 355 small block 435 hp 435 torque edelbrock performer rpm power package
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Re: pivot ball adjustment, info needed!

Postby cjbiagi » Sun Mar 29, 2009 2:50 pm

I wrote this a long time ago, but here is how I adjust the cable and pivot ball. It may vary a little from the earlier post, but again what you are trying to accomplish is with the clutch pedal all the way up and the clutch fork all the way to the rear you want to remove the slack from the cable. Then go and adjust the pivot ball to get your correct freeplay. Here it is:

Ok, here goes. What many people do on these cars is mistakingly adjust the nut on the end of the cable to get there pedal freeplay. This happens because some people don't even know about the clutch ball pivot on the top right side of the bellhousing.
What you want to do is make sure that the clutch fork is pulled all the way to the rear of the car. The return spring should accomplish this, but just make sure it is all the way back. Now you want to adjust the cable by turning the nut at the clutch fork to remove all the slack. You must also make sure that the pedal is all the way up, it helps to have someone pull the pedal up against the rubber bump stop while you adjust the nut to remove any slack in the cable. What you are trying to accomplish is, clutch fork all the way back, pedal all the way up, no slack in the cable. Once this is done now you can adjust the pivot ball on top of the bellhousing. The best way to do it is to actually measure the gap between the clutch disc and the flywheel when the pedal is depressed to the floor. For a diaphram clutch you should have about .030. The only problem is there is no easy way to measure this without an inspection hole in the bottom of the bellhousing. I drilled a small hole in mine, big enough to insert my feeler gauge. It has to be drilled at the point where the disc mates with the flywheel. At this point you loosen the large locknut on the adjusting screw and turn the pivot ball to get the proper gap with the pedal depressed, then lock down the locknut. Since most folks don't have any way of measuring this gap, the more common method of adjusting the pivot ball to result in 1" of pedal freelplay will also work fine. The important thing to remember is that you want the freeplay to be the result of a gap between the throwout bearing and the pressure plate fingers. Having freeplay as a result of a loose cable is not what you want. That's why you want to make sure that there is no slack in the cable to throw off your freeplay measurement. With no slack in the cable, the clutch fork will begin moving immediately when you start to depress the pedal. The clutch fork and throwout bearing will also begin to move immediately, taking up the small gap between the throwout bearing and pressure plate fingers (which gives you your pedal freeplay) and all will work fine. With the cable and pivot ball properly adjusted the throwout bearing will not be in contact with the pressure plate once the pedal is up and there will be no chance of clutch slippage since the pressure plate will be allowed to fully engage. Hope this makes sense, if not ask me again!
Clyde.........75 Monza 2+2
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Re: pivot ball adjustment, info needed!

Postby cjbiagi » Sun Mar 29, 2009 4:25 pm

There was actually a GM tool for the initial adjustment of the stud but it's been my experience that the position of the stud has little effect on the position of the fork where the cable attaches. As a result I have found that if you follow the adjustment procedure above it works out quite well. The important thing to remember during this whole operation is that the pedal freeplay must be the result of the clearance between the throwout bearing and the pressure plate fingers. Pedal freeplay from anywhere else is meaningless, it's just lost motion in the cable. The cable should be snug with the pedal up against the rubber bumpstop and the fork pulled all the way back. Now when you begin pushing the pedal you have no lost motion and the fork starts to pull immediately taking up the clearance between the throwout bearing and pressure plate fingers.
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Re: pivot ball adjustment, info needed!

Postby EagleFish » Sun Mar 29, 2009 5:53 pm

Clyde,

I agree and very well said.

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Re: pivot ball adjustment, info needed!

Postby 73astregt » Sun Mar 29, 2009 8:19 pm

clyde THANKYOU! i knew that info had been posted somewhere before on the site but i could not find it. this is another good piece of information that should be in the best of section! you guys agree?
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Re: pivot ball adjustment, info needed!

Postby MIKESMONZA » Sun Mar 29, 2009 11:37 pm

Moderators;
How about Moving this To Drivetrain Section Making it Sticky,,??
Or Even Better Make it; :arrow: "The Best Of"Posts"

Because We Have a Lot Of Request's like This,, Cause some us,,,
Like a 4-5-6 Speed, with,,
A Properly Adjusted Clutch,,Be it Stock Cofigurigation, or Other Upgrades,,

:dance: Thanks To Clyde Biagi,, Who wrote a Section on this Before,,
Maybe in the h-Body.org,"library"

:arrow: Espeacialy The ,Tip on the Hole Drilled For Measure Ment ,,
of Disk and Diapram,,,,and Flywheel Area,,

If any one Could add Pictures or Diagrams Of All of the ForeMentioned Parts,,
This Is FAQ,,
Edit 3-31-09,, :oops: ,I just Searched The "Best of Section"
And Peter Pan ;
has a Scaned,,Diagram for the Clutch cable assembly with instructions ,,,,"D I Y",,,,(Do it Yourself)
We Should Put them To geather,, :dance: :dance: ,Thank's
Mike
355,SBC,700R4Trans,3.42 rear,Sandersons,Edelbrock,Carb,Intake,Griffin,1,900 rpms at 60 MPH Highway Cruise Car.
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