Leaking wheel seal

[dgrinnan]

I recently had my differential rebuilt on my 47 WC.  I pulled the rear axles, replaced the bearings and the seals right behind the brakes.  Almost immediately the rear left wheel was throwing differential oil/lub on the wheel.  I ordered another new seal and this time I used some Permatex Gear Oil Gasket maker on the provided gaskets.  At first I thought that solved the problem.  I probably drove15-20 miles with no sign of a leak.  I took it out on a short run a couple days ago and once again I have oil all over my wheel.  Any suggestions?

Edited December 5, 2023 by dgrinnan

[Jerry Roberts]

Is the vent plugged on top of the differential ? And as  you probably know , the bearings are lubed with grease and not with the differential oil . Is the axle shaft worn where the seal rubs ?

[Jerry Roberts]

My parts book shows Two seals . Part # 17 is the inside seal . mopar 651678 .  Part #20 is the outside seal . mopar 891437 . 

[Jerry Roberts]

That part # 20 should be part # 26 . 

[PT81PlymouthPickup]

Yeah! I remember installing the inner seals on mine. I believe the inner seal could be installed backwards if not paying attention to the lip design which could make it leak.  Also, I too have seen axles with grooves worn in so deep that even a new seal won't keep the oil back. Been too long for me to remember for sure on mine, but if the axle is grooved, you might be able to reposition the inner seal a tad to a good surface on the shaft. It is possible to overfill a differential which could cause problems. The oil level should be just below the threaded drain plug hole.

[kencombs]

I typed up a big response and fat-fingered the enter.  Anyway, the inner seal is probably leaking diff lube into the bearing area.  The outer seal is intended to seal grease only and will likely not hold the lighter lube.  

[dgrinnan]

I will take a look at the inner seal.  Thanks for the feedback. 

[Jerry Roberts]

So you are about to get the problem with the inner seal sorted out and get the bearing greased . You might be wondering if every time that you want to grease the bearing , do I have to pull the axle shaft out ? No . There is a plug in the housing next to the bearing that you can remove and dab in a little grease . That plug has the same thread size as the wide base grease fittings on your truck . So why didn't Miss Mopar and Mister Dodge just put a grease fitting in there instead of a plug ? Because the bearing is protected by seals , one on each side of the bearing . You don't want to pressurize that area and blow out the seals . Dab in a little grease , turn the wheel to spin the bearing , and dab in a little more . Your shop manual will mention some of this . 

[Kilgore47]

I second the idea that the vent could be plugged.  I know this because I had to replace the rear shoes twice.  If the vent is plugged then as the housing heats up and builds pressure it will force the grease out on to the shoes.  Also had to re position one of the outer seals to a smoother part of the axel to stop a leak.

[dgrinnan]

I remembering seeing the vent.  How do I check it is open?  Does it screw out?  I think what I saw is the vent.  Is this the vent?

[Dodgeb4ya]

To remove said vent...Right below the 3/8" vent cap is a 916" hex...use a 916" wrench or deep socket to remove the all in one bolt/ vent cap.

Remove and clean it up.

[dgrinnan]

I pulled the vent and made sure is was clear.  I don't think it was blocked. (FYI - mine was 5/8s, not 9/16s) .  I won't be able to get to pulling the axle for a while to check the seals again.