? rear axle bearing seal

[laynrubber]

Pulled my one drum tonight to start my rear brake rebuild. Used my home made drum puller Then removed the whole brake backing plate, saw the shims but where is the seal to seal the outside of the rear axle bearing. I see the seal in the brake backing plate but should there not be a gasket under tha brake backing plate ?

[Dodgeb4ya]

There is a thick seal behind the tapered axle bearing- Pull the axle shaft out to service it. Then there is just the backing plate thinner seal. The shims are all that act as a seal against oil/grease leakage.

[laynrubber]

So in order of removal.....drum, backing plate (with axle seal pressed in backing plate), and then shims.

What prevents gear oil from leaking between the axle housing and the brake backing plate ?

Sorry if i seem dense

[james curl]

Isn't there an inner seal between the bearing and the gear lub?

[blueskies]

So in order of removal.....drum, backing plate (with axle seal pressed in backing plate), and then shims.

What prevents gear oil from leaking between the axle housing and the brake backing plate ?

Sorry if i seem dense

There is no gear oil in the outer axle bearing. The inner seal, behind the bearing, keeps the gear oil in the axle tube and center section of the rear end. The bearing is lubed with grease, and is seperate from the gear oil. There is a pipe plug on the bottom of the axle tube just in from the end behind the backing plate to put grease into the bearing. It doesn't take much, and it is a pipe plug instead of a grease zerk so that you can't pressurize the grease and push it through the seals. The outer seal that is in the backing plate keeps the dirt out of the grease, and the tight fit of the backing plate over the shims to the axle tube is enough of a seal there.

Pete

[Joe Flanagan]

I never saw the inner seals on my axle, so I assumed there weren't any. They are inside the axle tube where you can't see them I suppose. In any event, I replaced the bearings at both ends but did not replace the inner seals. I hope they're OK because I'm not taking it apart again.

[blueskies]

I never saw the inner seals on my axle, so I assumed there weren't any. They are inside the axle tube where you can't see them I suppose. In any event, I replaced the bearings at both ends but did not replace the inner seals. I hope they're OK because I'm not taking it apart again.

Joe-

Here's a couple of diagrams of the rear axle, and the seal in question- (click reload if the pics don't show)

The inner seal is number 8 in both diagrams. You can see from the first diagram that the seal sits just behind the bearing, and just past the grease pipe plug (#47) in the axle tube.

Hate to be the nay-sayer, but if you didn't see the seals, they probably weren't there... Without them, I don't think your bearings will maintain the correct lube.

Pete

[FMSPEED49]

There is a pipe plug on the bottom of the axle tube just in from the end behind the backing plate to put grease into the bearing.

Pete

Hmm, yup there it is, never knew that was there, thanks.

[laynrubber]

Well isn't that interesting i never knew there was a grease zerk for that bearing .......I will head out later tonight and check. This will explain the lack of a gasket. Thank you

[Dodgeb4ya]

Be careful not to blow the seals out with too much grease!

[blueskies]

Well isn't that interesting i never knew there was a grease zerk for that bearing .......I will head out later tonight and check. This will explain the lack of a gasket. Thank you

but it's not a zerk, it's a plug...

Pete

[Dodgeb4ya]

When I do new axle bearings I prepack them W/ new grease and put grease in the axle housing-I don`t take the plugs out to lube the bearings. When I want to just pump up the bearings in a so so don`t care car I pull the plug and screw in a zerk to get some grease in there, the right way is to take the axle out and inspect it and apply only new clean grease after washing out the old. You shouldn`t mix greases.

With a hand trigger gun you can feel resistance when your about to over-do it,then STOP!

[Young Ed]

Ya towed home a few junkyard relics after pumping grease into that hole. Fittings screw right in there

[Dodgeb4ya]

Yes Sur! Don`t like lookin back while towin a junker home and seein the axle a foot out side the fender!

[Normspeed]

If it's in good condition, is that outer seal, #4 in the pic, a tight enough seal to retain the gear oil if the inner seal fails?

[FMSPEED49]

I just pulled the plugs, and held the gun right up to the axle, gave her bout 6 squirts, and spun it, put the plug back in.

[38plymouth]

When you grease the bearing don't you have to screw something into the threaed hole to pump the grease in? My shop manual talks about screwing in a temporary fitting to grease it. What do you use, just a zerk fitting??

[blueskies]

When you grease the bearing don't you have to screw something into the threaed hole to pump the grease in? My shop manual talks about screwing in a temporary fitting to grease it. What do you use, just a zerk fitting??

Here's what the same book that the above diagrams came from says about the lube:

"Rear wheel bearings should be given a very small amount (about half an ounce) of short-fiber wheel bearing grease, medium, by removing the plugs as indicted by the arrow, and using a hand-operated pressure gun. Do not overlubricate. There is a special lubricant fitting with a valve arrangement that will allow only a small amount of lubricant to enter the bearing."

The lube chart in the same book says these bearings should be greased every 20,000 miles or two years.

Pete

[38plymouth]

Any idea what to use for this fitting? I never even knew there was a plug there until last night when I was reading the manual.

[Young Ed]

A regular grease fitting threads right in there. Thread it in give it a shot of grease and replace the plug. Rinse repeat

[FMSPEED49]

I didn't use any fitting, just held the end of the gun up to the hole and squeezed, while spinning the axle.

[ferdball]

Maybe I'm denser than I thought but How do I get to the inner seal, past the bearings. I didnt want to just start pulling on the axle?! I read through the shop manual but didn't find out HOW to simply get to the seal. I'm just doing all the breaks and ordered up the seals from Andy...now I just need to figure out how to get to it! DUHHH

OR since I see no oil coming out of the bearings should I not worry about the inner seal? Just looks like grease in there to me. I am probably just silly NOT to pull the bearings out and do it now but didnt want to have to get a tool to get the bearings out and then another tool to get them back in etc....? yikes

appreciate the help!

1948 b1b

Edited September 5, 2011 by ferdball

[busycoupe]

My inner seal was leaking a couple of months ago. I found oil dripping out of the brakes. To get the inner seal out I removed the backing plate, drilled a small hole in metal face of the inner seal then used a small slide hammer to pull it out. I think that I tapped the new one into place with a dowel, or a brass rod.

The leaking seal was one I put in four years ago. It was a leather seal that I got from Andy B. Perhaps I didn't install it correctly, or it may have been old and dried out, but for whatever reason it didn't last long. The new seal is neoprene, made by National. I hope that lasts longer.

Dave

[ferdball]

busycoupe: I'm a little confused. are you talking about the outter seal that is mounted in the backing plate itself? The inner seal I'm talking about is buried behind the bearings, does that make any sense? I dont know how to pull the bearings out.

This truck is so mix-n-match I just hope its the right rear end!

and thanks for the info on Andys Leather seals.

Edited September 5, 2011 by ferdball

[Andydodge]

Re the leather seals.......did you leave them in some oil overnight b4 installing?........andyd