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#1 |
Registered User
Join Date: Apr 2014
Location: Raleigh, NC
Posts: 51
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Can't measure rear end pre load, options?
I replaced the pinion oil seal in my rear end and the marks I made to put the nut back on did not hold up. I don't have the ability to take even more apart and measure pre-load. What are my options to get the yoke back on and be in a safe delta to not ruin my rear end?
GM Handbook just says basically, replace seal, and torque nut back down to 270lb ft. No mention of measuring pre load or anything. Wondering if that is my only option at this point. Thoughts? Thanks. |
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#2 |
Registered User
Join Date: Nov 2014
Location: Bigfork, Montana
Posts: 1,137
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Re: Can't measure rear end pre load, options?
Torque to 270 lb/ft.
I've changed more than I can remember, I usually do not torque the nut, I just tighten it down pretty darn tight. (No, that is not the correct way but it works) |
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#3 |
Senior Member
![]() Join Date: Mar 2003
Location: Colfax-California
Posts: 8,528
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Re: Can't measure rear end pre load, options?
My first question would be is what rear axle you are working on?
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#4 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,717
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Re: Can't measure rear end pre load, options?
I second kwmech. A 12 bolt won't specify torque on the nut because of the crush sleeve. A Dana will and I would assume an Eaton too.
But just use a 1/2" ratchet and tighten it as tight as you can get it. I HIGHLY recommend using a new pinion nut.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
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#5 | |
Registered User
Join Date: Apr 2014
Location: Raleigh, NC
Posts: 51
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Re: Can't measure rear end pre load, options?
Quote:
My fear in the job was around the crush sleeve. Wanted to get everything tight enough to be safe, without over crushing the sleeve. Should I get the nut going with an impact and follow with a torque wrench or breaker bar? I know some guys just eyeball with an impact. |
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#6 |
Registered User
Join Date: Nov 2014
Location: Bigfork, Montana
Posts: 1,137
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Re: Can't measure rear end pre load, options?
The important point is to NOT collapse the crush sleeve any more (changing pre-load). Tighten until no play & then tighten a little more ( i would go no where near 270 ft lbs)
It takes a lot of torque to crush a sleeve when it is new (i'm talking a BIG cheater bar!) but not so much after is has been "crushed". I hammer the nut on with an impact to approx 130 ft lbs. & call it good. ( apply non-hardening sealant to the splines & loctite to the threads) Before you remove the nut (too late now) you can measure overall turning torque at the pinion (this includes carrier pre-load & seal drag, etc). this gives you a target to aim for upon re-assembly & you don't have to gut the diff to measure just pinion pre-load. IMO, this is more accurate than marking the nut. |
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#7 |
Registered User
Join Date: Apr 2014
Location: Raleigh, NC
Posts: 51
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Re: Can't measure rear end pre load, options?
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#8 |
Registered User
Join Date: Apr 2011
Location: Klein Texas
Posts: 3,852
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Re: Can't measure rear end pre load, options?
It's a self locking nut so it's going to hard to turn. However, when contact between the bearing and crush sleeve is made it takes considerably more torque to turn the nut (it's trying to crush the sleeve). STOP!!!
That's the point which you removed the nut. Like mentioned, other axles use shims instead of crush sleeves to set the bearing preload so the pinion nut is just torqued in place.
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My Classics: '72 K20 Suburban + '65 Dodge Town Wagon '72 Corvette Roadster +'67 Corvette Roadster '73 Z-28 Camaro '63 Ford SWB Uni Pickup '50 Ford Coupe |
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#9 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,717
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Re: Can't measure rear end pre load, options?
Get a new nut and tighten it as tight as you can with the 1/2" ratchet. That should be fine and not crush the sleeve any further.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
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#10 |
Registered User
Join Date: Apr 2014
Location: Raleigh, NC
Posts: 51
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Re: Can't measure rear end pre load, options?
Thanks for all the advice. I tightened up the nut until there was no play, and then lined up the paint marks left behind on the nut and pinion. Worst case, I was off by one full turn of the nut. But it seems like I'm dead on. Took the truck for a spin, no leaks, no vibration. Appreciate all the help.
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#11 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,717
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Re: Can't measure rear end pre load, options?
Just be wary that a used nut won't "lock" quite as well as a new one and they are known to work their way loose. Should be good to go now, just check the nut occasionally.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
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#12 |
Registered User
Join Date: Apr 2014
Location: Raleigh, NC
Posts: 51
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Re: Can't measure rear end pre load, options?
Will do. I couldn't find anywhere with a new nut, so threw a good amount of blue loctite. Hoping that will help. Going to take some short trips and make sure everything is holding up still.
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Tags |
differential, pinion, rear end, seal, yoke |
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