12-Bolt Pinion Seal Replacement?

[joed]

I'm installing a 12-bolt rear axle from an 81 Chevy 1/2 ton in a project truck - more on that later.

The pinion/yoke area is pretty greasy, so I thought it would be a good chance to replace the pinion seal.

Having never done one before, I'm a little leery - I found a Chilton's type service procedure and it describes needing special tools, a crush sleeve, etc.

Has anyone done one? How difficult/tricky is it?

Any tips/tricks are appreciated.

Thanks.

Joe.

[DmaxMaverick]

If the bearings and gears are good, and you are ONLY replacing the seal, you don't need anything but the seal. The crush sleeve can be reused, and there's no need for gear setup. Replace every piece EXACTLY as it was removed. Mark the nut location (clearly score the nut and pinion end) and count the removal turns. Reuse the sleeve, and return the nut to the exact previous position, same turns and line up your score marks.

If the pinion shaft appears to have corrosion, pitting, or other damage near the seal area, you can use a "Speedy-Sleeve" to get it to mate with the new seal.

I'm a big fan of the 12-bolts. I have one from a '78 in my Blazer. It cured frequent repair/replacement of the original 10-bolt. It's very versatile, with gear sets available from 2.23 to 4.56, and Auburn makes a very nice L/S carrier for it. Mine is 4.10 with the Auburn L/S.

[joed]

Thanks.

Is it necessary to measure the torque on the nut before removal? I would think installing it with same number of turns accomplishes the same thing.

Only special tool needed a seal puller?

[JohnC]

Thanks.

Is it necessary to measure the torque on the nut before removal?

No. The point (and critical issue) is to get the assembled length exactly the same.

[DmaxMaverick]

Correct. Disregard the torque. Using a torque value will foul the setup. The torque should ONLY be used when installing a NEW sleeve with a NEW nut.

You won't need any special tools. Be sure to index the yoke spline the same, as well. It's best to "lock" the diff/pinion before you start, with the yoke in a right angle position, so there won't be any guesswork. Mark the "UP" position, and make sure the axles/pinion doesn't turn before reassembly. DO NOT engage the "soft" part of the seal during installation. It will leak, for sure, if you do.

[Robyn]

Ditto's on this one.

The only thing I can add is to wash the threads off with brakeKleen just prior to installing the nut back on and add a little BLUE loctite to the threads just before screwing the nut on.

This will assure that the nut does not back off.

Good luck

Missy