Jason M 91Z

I had my 97 rear apart for sandblasting, and I replaced the tail pinion bearing and race (small one). I left the head bearing and race however, because they both still look brand new. They only have 30K on them. Pinion preload was 12-14" lbs. before, and when I put the new rear bearing in and new seal, I set it at 20"lbs, which is pretty much in between the spec for new and used bearings. What to you guys think, especially you GMTech. I used a new crush sleeve and nut too.

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-Jason M. 1991 Camaro Z28

82camaro

You should be OK. Just don't run it hard, or for very long until the new bearing is broken in. The problem is that the new bearing will wear in and the preload will reduce. Hopefully it won't reduce to the point that the used bearing is too loose. Should have replaced both bearings.


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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

Jason M 91Z

I knew I should have replaced them both. Only sucky part is i have to get the head bearing pressed off the pinion cause I don't have the right stuff. I took the rear apart tonight and I already put new Timken axle bearings in, so I'm going to do the remaining pinion bearing and the carrier bearings. May as well just to it once. I shouldn't have to set the backlash again right? Aren't the bearings supposed to be the same size?

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-Jason M. 1991 Camaro Z28

82camaro

Backlash should be OK, but check in anyway.

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82 camaro--original steering wheel, brake/gas pedals, seats--everything else modified
82camaro

GMTech

As long as you don't swap the shims around, backlash won't change.

You should have done both bearings at the same time. Like you already know, new bearings require more pre-load than used bearings. So now that you tried to get "in-between", the new bearings don't have enough and the used have to much.

And no, there are two different size pinion bearings, just like front wheel bearings.

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'97 Bonneville SSE

ede

as gm tech said bearings should be the same size. once i got a replacement bearing, can't remember who made it and it was a few thousandths differant. i miked them and just added or subtraced shims as i needed. i still doubt if it would of changed back lash very much. after that i always measure bearings to make sure the height is the same.

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ICON Motorsports

1st & 3rd
MM Black Diamond 538 F&AM

Jason M 91Z

Thanks guys, just picked up the bearings, crush collar, and new pinion nut and some limited slip additive from the dealer today. I already put new Timken axle bearings and seals in, and now I just have to get my head pinion bearing pressed off and have the new one pressed on. I'll set the pinion bearing preload to about 25 in/lbs. They're all new Timken bearings and races in ACDelco boxes. Thanks again guys, I can't wait to get this rear in with these huge brakes, and try out my new 1LE front brakes!

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-Jason M. 1991 Camaro Z28