Rear End Seal Leak Advice Needed

[sick472]

My 72 RHA 3.07 rear end developed a seal leak on the drivers side this weekend and I will be replacing both sides while I am at it. I have done this repair on a 76 C10 and need to do some research on what might be different between the two. I know the brakes are in good order (minus some possible oil on the shoe pads). I'm happy with the gear ratio even though it's limited slip, not posi.

What else should I do while I have it emptied and tore down?

Front seal?
Check gear lash/shims?

Any references for procedures or "how to" videos would be great too. Thx!

[Steeveedee]

If the diff ain't making noise, I wouldn't bother with checking lash, personally. If the pinion seal isn't leaking, I wouldn't touch it. I don't recall if the bearing and seal are separate items on that diff, but if they are, the bearing gets replaced when the seal leaks. I use brake cleaner to get the diff oil off the parts. If you don't have any, Easy-Off is basically what's used in a hot tank. That or Purple Power will cut the lube as well.

[BigBird05]

Since you have the axle shaft out inspect the bearing surface of the shaft for wear. Better to check it now, then to have a problem later.

[sick472]

Thanks folks! I pulled the axles out and everything looks pretty good, even the bearings. I may change the bearings anyhow. They are not pitted, but do have some very minor discoloring . I know they have been in there since I bought the truck in '95. The axles are nice and smooth where the bearing ride with no obvious grooves or lips from wear. Even the gear teeth look good. I will also swap all the shoes out since one was soaked in gear lube and both sets were well used anyhow.

I'm hoping Napa will loan me the tools to do the bearings.

[BigBird05]

Since the bearings look good I would not touch them. They are probably better quality then you can get today. Just replace both seals.

[gmc684x4]

Leaking axle seal is usually showing there may be bearing wear occurring there

[sick472]

All, Thanks for joining my thread. The wear on the shafts (bearing and seal areas) look to be minimal. I have opted to leave the bearings alone and just replace the seals AND brake cylinders as the rear-end was "cleaned up" and just painted many, many years ago when the budget was minimal. The truck just hit the road and I am sure the seals are just tired along with the brake cylinders (one was showing slight signs of leaking). It's quite possible that these parts are 40 to 50 years old.

All in all, the worst part of doing this job was the unknown going into the pumpkin. It's a simple operation now that I have it all apart.