The Stovebolt Site Forums The Shop Area Driveline Rear wheel seal leak

I noticed fluid on the back rim of my 58 3/4 step van. From different posts I read, I guessed rear wheel seal was bad. Brakes and hardware were layered in black gunk. The seal looked ok, but what do I know-I then read about other things that might cause leaks. Too much fluid, some axle vent? At this point I will likely replace the seal anyway. I also remember this leak coincided with my differential swap. Coincidence? Anyway, could someone please school me on what might going on.

Chaz 58
If you pulled the axle all the way out of the rear end housing, you may have dragged the axle splines on the rubber seal. Damaging the seal, thus the leak. Just a thought.

Possibly. I couldn't detect any damage to it though.

A worn axle bearing that allows the axle to bounce up and down on the seal, or a worn surface on the axle shaft where the bearing rides is the most common cause of a leaky seal. Try to move the axle shaft up and down with the brake drum removed. Anything other than a very tiny up/down movement is too much. If you can see the axle move up and down, replace the bearing and/or the axle as well as the seal. There's no way to get all the oil out of the brake linings, also.
Jerry

I had no movement when moving the axle shaft. I read about the brake pads needing replaced. They were looking a little thin anyway. Is there a "best" way to knock out the seal. I'm a little worried about getting everything back together right. I took pics, so...

I use a big pry bar and just manhandle the seal out of there. Be sure to inspect the axle shaft just inboard of the flange for pitting, scoring, or other damage. Sometimes there's a wear ring where the axle has been running in the bearing, noticeably smaller diameter than the rest of the shaft. If so, the axle is junk.

Lincoln did you ever hear about anything about high fluid level or vent being clogged causing seal failure? I briefly looked for a vent on my axle but did not see any trace of it.

He said this is a 3/4 ton. It will have full floating brgs. The vent is a little noggin somewhere on top of the housing. It has a little cap on top of a tube. If you can wiggle the cap, generally the vent is clear. Too much rear end grease can cause it to leak. It should be level with the plug on the rear cover. You more then likely have a bad seal.
George

I wouldn't replace the shoes without doing the seals. The hub bearings need to be adjusted correctly in order for the seal to work.

How old are the seals? Seals don't last forever, sounds like a bit of over-thinking going on. Even new parts can fail, or maybe they were installed incorrectly if they were recently changed.

Glad you caught this, I was about to chime in!

Glad you caught this, I was about to chime in!
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Yes, the axle doesn't ride on the brg. The seal doesn't ride on the axle shaft.
George

I use the end of the axle shaft to pry out the bearing.

OOPS! I missed that "3/4 ton" part! If those seals are leaking, you've either got a bearing problem or improper preload on the adjusting nuts that retain the hubs. The seals are very sensitive to nicks and tears while the hubs are being installed.
Jerry

Are you sure it's not brake fluid from leaky cylinders?

No, it's definitely the differential fluid. I ordered a seal, so now I wait.

Do you have a shop manual? If not, you can find useful info here in the 55 Truck Shop Manual. Good luck.

The new seal is on. I'm putting on the retaining nuts. How tight should they be? The hub spins about half way around with one spin right now. Thanks for the manual sir.

You're welcome. Glad it worked out.

I usually tighten the inner nut firmly, enough to require a little effort to turn the hub, then back off slightly until one of the lock ring tabs can be bent down to secure the nut. Then tighten the outer nut securely with a socket or a flat-tipped punch and bend a lock tab outward to retain its position.
Jerry