Can't measure rear end pre load, options?

[abohler1]

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.

[B. W.]

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)

[kwmech]

My first question would be is what rear axle you are working on?

[Mike C]

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.

[abohler1]

Originally Posted by kwmech

My first question would be is what rear axle you are working on?

It's a 12 bolt rear. The handbook doesn't get into which rear end the pinion seal change applies to. Just mentions the torque spec for the nut. Quite vague in my opinion.

[abohler1]

Originally Posted by Mike C

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.

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.

[B. W.]

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.

[RustyBucket]

Be careful with an impact wrench.... just bought a new cheapie Harbor Fright "EARTHQUAKE" model. They claim it's got 800ft.lb. of torque... maybe they've got little feet in China.
That being said I've replaced 2 pinion seals in a lifetime(one 12bolt car & one 12bolt truck) and was always concerned about too tight. Think I didn't get 'em tight enough because I eventually had noisy pinion bearings in both.

[Bigdav160]

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.

[Mike C]

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.

[abohler1]

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.

[Mike C]

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.

[abohler1]

Originally Posted by Mike C

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.

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.