Tightening Pinion Nut

Discussion in 'Transmission & Driveline Topics' started by 7dcamaro, Jul 23, 2014.

  1. 7dcamaro

    7dcamaro Veteran Member

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    My 12 bolt rearend in my 70 Camaro was leaking and discovered that the pinion nut was loose...way loose, could turn it with my fingers.

    Ive got a new nut on order and have done searches here and found I need to torque it to 150 ft. lbs. Am I gonna be able to do that with a torque wrench without the car being on a lift where I can get good leverege?

    Whats the best method without availability of a lift? Rearend on ramps....trans in gear.....wheels chocked......or what?

    Any advice on the method to do this would be appreciated.
     
  2. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    That nut was used to crush a sleeve until a set rolling preload was achieved on the bearings. Anything you do at this point aside from taking the rear apart, taking the carrier out, and measuring the rolling preload as you tighten the nut is going to be a guess. Torquing to 150 ft lbs may or may not result in a noisy rear and premature wear. Had the nut been marked relative to the yoke while it was still tight, you could line the marks up again and get close, but without those marks, I'd want to measure the actual bearing preload rather than risk ruining the ring and pinion.
     
  3. APEowner

    APEowner Veteran Member

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    I have never seen a pinion nut loosen up without there being additional internal damage. I think you're wasting your time just replacing the nut. On the other hand it's not much time so why not give it a try? There's no way to get it exactly right without taking it apart so I'd just run it on and tighten it about 1/16 of a turn after it seat on the yoke.
     
  4. 7dcamaro

    7dcamaro Veteran Member

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    Thanks for the replies..... but they didnt answer my questions. Anyone else got any input.

    I know all about the crush sleeve and proper preload but at this point without tearing it all apart and reassembling with a new crush sleeve, tightening the nut is all I can do. Ive already tightened it snug and drove it and it seems fine. So Im gonna put a new nut on it and tighten to 150 ft lbs. Verified this with Moser any they said it'd be fine.
     
  5. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    What you are trying to do would be equivalent to trying to install cylinder head bolts that give you a torque to angle spec by guessing and just torquing to some arbitrary static torque value. You are not measuring the correct parameter for torquing a pinion nut by using a click type torque wrench, so what torque you pick, is kind of arbitrary. You are praying that the torque value you pick does not crush the sleeve any further and disturb the rolling bearing preload, and yet is tight enough that it doesn't come loose under power. You can pick 135, 160, whatever, it's still shot-in-the-dark guessing. Not wanting to take the rear apart doesn't make this method any more right.
     
    Last edited: Jul 23, 2014
  6. 7dcamaro

    7dcamaro Veteran Member

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    wow dude
     
  7. Protour-Camaro

    Protour-Camaro Veteran Member

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    Bondo is spot on. The nut is not ever torqued and is tigtened to achieve a pre-load on the bearings. There is a torque out there that is in theory tight enough to keep it from loosening and not effect the pre-load, but since it was already loose, I would dis-assemble as a piece of mind. A failed rear-end could be disasterous.


    Than again, you could torque it to 150 and be perfectly fine. I suggest just throwing it on jacks,
     
  8. 7dcamaro

    7dcamaro Veteran Member

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    He IS spot on......as is your response......and I understand all that.......but all that didnt answer my questions.....I give up.
     
  9. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    You can use jackstands or ramps. If you use jackstands you'll need good working parking brakes to hold back your wheels from turning when you tighten the pinion nut. Ramps are probably more stable. The advantage to using jackstands is that if you need to rotate the driveshaft to access the drive shaft yoke bolts when removing/installing it, you can. I'd use the large style SUV jackstands under the axle tubes if I used jackstands. They have a larger footprint and go up nice and high. Tighten the pinion nut til you fart, and then go 1/8 turn more.
     
  10. 351maverick

    351maverick full time Ebay seller/hustler/car killer

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    I'd tighten the effer to 150 ft/# & call it a day

    BIG pipe wrench on the yoke will prevent movement while tightening
     

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