Rear Axle set up/52 3/4 ton b3

[Guest brewbag1]

Ok u grey beards....how the heck do I set up the rear axles on this beast? Original b3c with chrysler floating type axles. When installing axles and brake back plates ther is about 1/8 in floating end play in the axle. So the inner bearing is not seated completely in its cone. The existing shims only shim out the back plate. they dont actually shim the outer race of the inner bearing. Seams the outer race needs to be shimmed so it fits tighter against the bearing.

Are there special shims just for this (to push the outer race inward)?

or;

are the drums, wheels supposed to have that much float?

service manual doesent address short of a spec which says 3 to 5 thousanths end play.

My take is I should shim the bearings untill the axle only moves 3-5k.

Any old time takers who have done this interested in commenting?

I can launch rockets, but cant shim an axle!

[Merle Coggins]

The shims behind the backing plate are for adjusting the bearings. When you remove the shims, it pushes the bearing cup (outer race) tighter onto the cone to reduce the end play. If all of your shims are removed and there is still end play (loose bearing) than the thrust block in the differential is worn. The thrust block sits between the side gears in the differential and is used to position the axle shaft and allow the axle bearing preload to be set. If the block is worn, then the axle can retreat further into the diff and you will run out of adjustment. If you can find some narrow shims to press the bearing cup further into the housing, you may be able to achieve the proper bearing adjustment, but you may find other problems, as the axle shaft is set further into the axle, which will set the brake drums tighter against the backing plate, etc.

Also, are you sure your bearings are in good shape? A worn bearing may be causing the same symptom.

Merle

[Guest brewbag1]

First, thanx for the response. Sounds dead on. Except, both axles fit this way, both bearings are/were in good shape. Does the thrust block wear evenly so both axles would slip in farther as it wears? Am replacing 1 bearing due to a cracked cage. I did not want to pull the differential if i could avoid it!

Lee

[Guest P15-D24]

backing plates fully installed and bolted in.

[Merle Coggins]

Good point, GT.

The thrust block, I believe, is not permanetly attached inside the diff. If you are trying to set up the bearing on one side without the other axle in place, you will push the block over and can't get the bearing tight. You need tension on both sides of the thrust block to center it, then set up both bearings together.

If both axles are in place and you can't get the bearings set, then I'm afraid you don't have much choice but to address the thrust block in the diff.

Merle

[Guest brewbag1]

Ok, So I did not check end play with both axles installed. I will do so before condeming the diff.

Thanks for the advice/help.

52 B-3-C long bed. Still up on jacks!

[Guest brewbag1]

Well, a little more info. installed both axles/brgs. both bearing races are inside the axle flange by about 1/16th inch. Thrust block is installed.

has anyone seen a thrust block wear this much?

[grey beard]

Merle is telling you what you need to know here. Couldn't do better myself. The only other thoughts I have had on your prtoblem are these:

1. Are both backing plates clean and free from scoring in the bearing area where they back up the bearing? Do either show any signs of scoring from close encounters with a siezed bearing in a past life?

2. Before you pull the center member, check the numbers on your bearings. Someone may have installed a "will-fit" bearing in the past that had the correct external dimension but was too narrow in cross section. This suggestion takes only a few minutes and is easy to do.

If you do not have access to parts books and bearing numbers, find your local Bearings Inc. store and give them the numbers. Since your problem is mighty unlikely to happen, I'm betting on your finding the wrong parts installed somewhere, and the bearings are most likely suspects. Are both bearings the same thickness?

Please let us know what you find, so we will all be smarter in the end.

Lots of luck.