# What would cause this throw out bearing damage?



## EdR (Sep 2, 2014)

Hi. Replacing my throw out bearing. The old bearing itself seems fine but the part the arm rides in is all broken up. Any ideas what would cause that? Just don't want to have my new one get destroyed shortly after I put it in.


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## geeteeohguy (Feb 2, 2008)

Looks like a cheap bearing with a cast flange. Get a bearing with a machined steel flange. I've never seen this happen in over 35 years working on these cars. Must be an off-shore part. Make sure to apply a small amount of grease on the fork where it rides against the bearing.


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## EdR (Sep 2, 2014)

geeteeohguy said:


> Looks like a cheap bearing with a cast flange. Get a bearing with a machined steel flange. I've never seen this happen in over 35 years working on these cars. Must be an off-shore part. Make sure to apply a small amount of grease on the fork where it rides against the bearing.


Thanks. I bought a Hays "Performance" throwout bearing from summit to replace it and it looks identical to the one that I'm taking out (minus the damage). Maybe I should return it. What brand/model would you recommend?


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## rickm (Feb 8, 2012)

better check your clutch fork ball stud for excessive wear before you re-assemble.


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## geeteeohguy (Feb 2, 2008)

The one I installed in 1984 (that's still in service) is a McCleod part. But, back then, all this stuff was made in the USA and of good quality. Now, not so sure.


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## PontiacJim (Dec 29, 2012)

I believe I recognize that problem. My throw-out bearing did the same thing EXCEPT the piece that broke off the collar went into the clutch assembly taking out one of the hub springs which then took out my pressure plate. Had'nt put much mileage on the car and $400 went right out the window.:banghead:

This is what I found. I purchased a replacement *aftermarket* (not original)GM clutch fork that was supposed to work. Nice heavy duty piece. Fit the throw-out bearing well & nice and tight. Snapped right onto the clutch ball in the bellhousing. Clutch linkage all lined up and fit as factory. Yep, thought I had something that was going to be around for a good 200,000 miles.

Here's the problem. The area on the clutch fork where it slides over the throw-out bearing appears to be generous enough, but once you clip it to the clutch ball, it positioned the inside edge of the clutch fork too deep onto the collar of the clutch bearing. The linkage pushes the clutch fork, which pivots on the clutch ball, acting like a fulcrum/lever and......... the inside edge of the clutch fork does not have enough clearance to pass by the collar and hits that collar with all that leverage and breaks it off. It is hardened, so it does not bend.......it snaps off. From your photo, looks like you nipped yours several times. Mine just took off one big piece, like about 1/3 of the collar and did all my damage.

The replacement fork is generic. DO NOT USE IT!. I found a junk yard out west that actually had a '68 Lemans 4Dr with a factory 4-speed parts car. He still had the clutch fork, so I bought it very reasonably -because at the time all you could get new was the aftermarket "supposed to work" GM style clutch fork. Problem solved with the used '68 fork and setting them side by side you could see the difference in the pocket that held the throw-out bearing.

Now available is a factory correct aftermarket replacement clutch fork. I purchased one in hopes it might be as factory as my original '68 clutch fork. Sure enough, a perfect match in all dimension. 

I can't seem to find my receipt for the clutch fork, but I believe I got it from the Original Parts Group catalog. It sells for $79.99. I am sure other Pontiac parts specialist have the same part and perhaps cheaper. You want the one that is factory correct.......and nothing less.:thumbsup:


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## geeteeohguy (Feb 2, 2008)

Now THAT would explain the whole thing. Sounds like that's what really happened here. Having never dealt with an aftermarket clutch fork, I was, of course, clueless!!


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## EdR (Sep 2, 2014)

PontiacJim - Thanks so much. That make a lot of sense. Now that you mention it when I bought the car the prior owner told me a story about having to drive the car in 3rd gear all the way home one time and he ended up having to replace the fork and throw out bearing. At the time the discussion was about the ridiculously low gearing the car had, but now it all makes a lot more sense. He very likely used a generic after market fork.. thus the low wear on the bearing and the damage. I'll be ordering an exact replica fork momentarily. Thank you for saving me the trouble of another clutch/bearing job in a few months!


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## PontiacJim (Dec 29, 2012)

EdR -"Thank you for saving me the trouble of another clutch/bearing job in a few months!"

No problem.....that's why they pay me the big bucks!:rofl:

My overall experience in life is that if it can be broken, destroyed, abused, caused to fail, or leave 'em scratching their heads trying to figure out what went wrong because "that's never happened before" or "we simply can't explain it", well, I'm the guy who can do it!:yesnod: If it wasn't for bad luck, I would have no luck. Anyone else, it'll work like it is supposed to. But me......I can f*ck anything up without trying. What a great way to learn, and to know what works and what doesn't.:bannana: Its also very costly too boot. I think I should apply for a position at Consumer Guides because I could guarantee you could trust my opinion and overall ratings on any product.:cheers


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