Rear Axle Seal leak!

[uteman1011]

Hey all,
1978 C20 with the 14 bolt floating axle. I've replaced the right rear seal 3 times (including bearings) and it continues to leak!! Doesn't feel like any slop in the fit. The seal appears to fit correctly. I'm at a loss. Any ideas what might be going on?

I've read that you can possibly overfill the axle oil?? I've just filled to the fill plug where it just barely comes out.

[tucsonjwt]

I had the same problem with the shop that serviced/inspected my 83 C20. If you search rear axle seal leaks for 3/4 ton GM pickups you will find this problem existed as far as into the late 2000 model years.

GM came up with a fix which is a two piece rear "wheel seal", which is what they call the rear axle seal. It is sort of like a 2 piece bearing with an inner and outer "race." I forget the part number but if you call your GM dealer they will have two different part numbers listed for the wheel seal, and you need to buy the newer part number.

Let me know if you can't find the part number and I will try to find it again.

[tucsonjwt]

You can read a discussion on this for later model 3/4 GM pickups, but I think it applies to square models also.

http://www.dieselplace.com/forum/76-...-problems.html

[Shady Rascal]

Also be sure and check that the axle breather hose isn't plugged up. When they get plugged up the pressure has to go somewhere and you'll get seal leaks.

[uteman1011]

Thanks for the replies! I'll check that breather tube this afternoon and give a dealer a call to see about the 2 piece seal.