Author Topic: 3866568 Clutch Pivot Stud Thread Size  (Read 833 times)

jeff68

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3866568 Clutch Pivot Stud Thread Size
« on: June 22, 2012, 05:51:30 PM »
I recently picked up a new GM clutch bellcrank pivot stud.  This is the stud that screws into the engine block, and the bellcrank (z-bar) pivots on it.
I want to confirm that I got the right part, since it didn't have any original packaging with it.  I know the correct GM part number is 3866568. My car is at the body shop so I can't get to it right now to confirm.

Can someone please confirm what the correct thread size is for this stud.  Thanks.

This is what I bought:
68 L30 / M20 Convertible
Ash Gold

bertfam

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Re: 3866568 Clutch Pivot Stud Thread Size
« Reply #1 on: June 22, 2012, 06:43:01 PM »
that's the one. The thread size is 1/2"x13

Ed

jeff68

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Re: 3866568 Clutch Pivot Stud Thread Size
« Reply #2 on: June 22, 2012, 07:25:50 PM »
Thanks Ed.  I'll verify the threads this weekend.

Background:
When I was researching the 3866568 stud, I found some info about the threads being 3/8"-16.
This is what a place called Pontiac Paradise has to say about it:
http://pontiacparadise.com/shoptalk/2011/01/

They also have an ebay auction with similar info:
http://www.ebay.com/itm/NEW-Reproduction-GM-Ball-Stud-used-60s-70s-GM-/250759330161?hash=item3a626bb971&item=250759330161&pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr

I also found some posts on Team Camaro about the threads being 3/8"-16.  You can't always believe what you read or see in the internet, so I wanted to be sure.  I'm fairly sure the threads on the one I have are 1/2"-13.
68 L30 / M20 Convertible
Ash Gold

bertfam

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Re: 3866568 Clutch Pivot Stud Thread Size
« Reply #3 on: June 22, 2012, 08:18:44 PM »
I don't believe there's any difference between the big block and the small block (or even the L6 for that matter), but in my case that measurement is from a big block.

Ed

jeff68

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Re: 3866568 Clutch Pivot Stud Thread Size
« Reply #4 on: June 22, 2012, 11:09:42 PM »
^^Correct, they are all listed as the same.

Just checked and the threads are 1/2"-13.  Thanks for your help.
68 L30 / M20 Convertible
Ash Gold