The Stovebolt Site Forums The Shop Area Driveline rear axle seal replacement - oil deflector??? 1948 3100 1/2 ton

The right rear axle seal is leaking badly in my 1948 Chevy Thriftmaster 3100 pickup (see attached picture). Obviously the axles need to come out in order to replace the seals, which is explained under Axle Shaft or Drum removal in section 4-3 Rear Axle of the Chevrolet Truck Shop Manual.

However, under "Replacement" on page 4-3, it talks about installing a gasket to the hub aligning the center hole of the three holes closest together with the notch in the hub, then install the oil deflector over gasket aligning oil pocket with notch in the hub. Then it goes on to say I need to insert six special bolts and force the heads down onto the deflector and peen the end of the shoulder on the bolts into the counter-sink around the bolt holes in the flange. Figure 4 shows a picture of the axle in a holding fixture on a bench where it says you are peening the flange bolts.

I don't see anything explaining these hub gaskets or oil deflectors or a disassembly procedure for them. It seems like it was a bit of an oversight of the author of the shop manual to not explain a disassembly process for this oil deflector that I assume is on the axle shaft itself.

Can anyone here shed some light on this?

The gasket and oil deflector are held in place by the wheel studs on the inside of the axle flange, and unless the gasket is severely compromised (any oil on the outside of the deflector opposite the drain hole?) then there's no need to remove the wheel studs to replace the gasket. The deflector is supposed to route oil seepage to the outside of the axle flange and brake drum. The best way to remove the wheel studs is with a ball joint press (see pic) that's way easier than driving them out with a hammer and potentially damaging something.
Check to be sure that your axle tube vent is not clogged, which will force oil out the axle seals as the axle heats up while driving.

The axle vent did have dirt build-up around it, but I'm not sure it was plugged enough to allow pressure to build inside the axle. In any case, it has now been cleaned, so it should no longer be a concern.

There is oil covering the entire axle, inside (facing the brakes) and outside facing the drum. Does this mean the oil deflector gasket is bad? I have a roll of gasket material, can I make a new gasket for the oil deflector - or is this something I need to buy (where)?

It's really doubtful if the gasket is bad. I would clean things up and inspect before making a decision. Replacing all the wheel studs isn't a trivial matter.

I agree with Kevin that the gasket isn't probably an issue. More likely a failed axle seal. But (a big but), have you checked your fluid levels in the axle and transmission??? If you still have the original torque tube setup, and the seal in the transmission end of the tube has failed, it will allow transmission fluid to travel down into the rear axle causing it to overfill and create excessive leakage/failure of the axle seals. Just offering another thing to check to help confirm or eliminate as a possible cause. Either way, you need to replace that axle seal for sure.

I drained the rear axle and pulled both axle shafts. It did not seem like I got an abnormal amount of oil out of the differential.

The good news is both axles are good and both outer axle bearings are good. The seals appear to be original (1948) and are simply worn out from use. New seals and brake shoes are on the way.

When you change the shoes remember to inspect the backing plate pads for any grooves. When assembling the brakes put a thin film of anti-seize on each of the 6 backing plate pads. Not much and don't get it on the brake pad surface.

Twin Jimmys, There were some groves in the backing plate pads where the shoes contact them. Welded those groves up and ground them down to where they should be. Will use anti-seize sparingly.

The quality of seals these days are so much better than they were back then they quit putting all those deflectors on. The deflectors didn't work that good as you can tell.
New seals & shoes should take care of it. You need to o-haul or replace the wheel cylinders. They don't have any deflectors.

George