Axle Shaft Bearings

[RHO]

The manual says to lubricate, remove the pipe plugs and temproarily install lubrication fittings. Open the vent valve hole above each pipe plug holr with a piece of wire before lubricating.
Two questions:

Even though the axle has been cleaned, I can find no vent hole on either side.
Why cannot I just use a grease gun an squirt the grease in there until it tries to back out the pipe plug hole?


'55 Commander
'55 President

[Bud]

If you continue to pump grease into the bearing flange without cleaning the vent hole, you risk the chance of contaminating the brakes because the grease will bypass the outer grease seal on the axle flange especially if it hasn't been replaced in recent history. Please don't ask how I know about this. Bud

[RHO]

Thanks Bud, but even though the service manual shows a drawing of where the little vent hole is supposed to be, it must be really really small because the axle has been cleaned and painted and I am unable to find the hole. Do you know if it is on the same side as the pipe plug or opposite or up high where you need a mirror?

'55 Commander
'55 President

[StudeRich]

The axle tube vent is only a tiny pin hole usually drilled on the top, or an hour or less forward or rearward of top center on the axle tube and about 8-10 inches from the backing plate, on later axles I have only found one on the drivers side, but the early ones with the grease plugs may have one on each side.

These would only vent the axle (Diff.) inside of the seals, not outboard of the seals where the bearing is, so they must be talking about another vent somewhere. [?]

I would not put more than one pump of a hand pump grease gun of grease in there, to avoid blowing the seals.

I think the only way to do this on an unknown condition car, is the hard way, I think you know what that is!

StudeRich

[RHO]

OK, I found the vent holes on the very top up near the edge. Got 'em cleaned out with small wire and found a grease fitting in the tool box, so next I'll do the one pump of grease. Thanks for the help.

'55 Commander
'55 President

[jclary]

If you have the holes cleaned out...pump until a small amount of grease weeps out the hole. Don't be timid, they are not that delicate.

John Clary
Greer, SC

Life... is what happens as you are making plans.
SDC member since 1975

[Bud]

There should be a hole in the backing plates on the bottom side of the axle housing flange that is supposed to vent the old grease from the bearing when pumping in fresh grease. I've never trusted pumping grease into the rear bearings using a grease gun. I've had grease bypass the outer seal contaminating the brake lining. It's also not a good idea to mix greases as you can end up with a bearing failure due to the mixing of different grease formulations. The different formulations are not compatible with each other. If you don't know when the bearings were last inspected and repacked, I would recommend dissassembly for inspection and cleaning of the bearings and then repack them by hand. Bud

[RHO]

Thanks for the advice. We repacked the driver side but the other side is unknown. We'll proceed with caution.

'55 Commander
'55 President