Rear Axle: Excessive end play

[Harryhawk]

Hi, I have excessive end play after over hauling the rear axle with all new parts, about 40thou before using any sims. I followed the manual and the advice offered on the forum. Can anybody help with an explanation of what's happened or what I've done? Cheers Harryhawk

[JoeHall]

If your overhaul included new bearings on the old axles, you may not have pressed the new bearings as far onto the axles as the old ones were. That's why it is a good idea to mark the location of the old bearings before pressing them off. In pressing the new bearings on, ever how far you stop short will show up as extra end clearance when you install the axles. Since you now have an extra .040" end play, I'd put each axle back in the press and see if I could not get another .040" of movement, collective between the two bearings.

[Ron Dame]

The reinforcement should be outside of the brake backing plate, though that would leave more like 0.25" of excess play. I'm leaning towards Joe's theory.

[Harryhawk]

Joe Hall & Ron Dame thanks for your replies. In the rear axle over haul I used new bearings, races, inner and outer oil seals & gasket on the old axles. It took little force to remove the old bearings so I pressed the new bearing on only lightly. Joe I will try what you suggested by pressing the bearings a little further, but wouldn't that cause a bigger gap between the bearing and the race there by increasing the end play. If you have the time could you please explain a bit more, your help is much appreciated. Cheers Harryhawk

[Dwain G.]

Is this a Twin Traction rear end?

[Harryhawk]

Dwain, thanks for your interest. It is a Std Dana 44 in a 62 GT. Any comments and suggestions are much appreciated. Cheers Harryhawk

[JoeHall]

Joe Hall & Ron Dame thanks for your replies. In the rear axle over haul I used new bearings, races, inner and outer oil seals & gasket on the old axles. It took little force to remove the old bearings so I pressed the new bearing on only lightly. Joe I will try what you suggested by pressing the bearings a little further, but wouldn't that cause a bigger gap between the bearing and the race there by increasing the end play. If you have the time could you please explain a bit more, your help is much appreciated. Cheers Harryhawk

Yes, you are correct, pressing the bearing(s) on farther results in more shims needed. Brain fart on my part. It's the reverse, to reduce shims, you'd need to press the bearing the other direction. But the way you describe the bearings' light press fit, that may not be advisable. Perhaps you pressed them on too far, but that's hard to do, because the axle surface is tapered, so the bearing sort of hits a wall when pressing it on.

Regardless of the above, how much shimming is too much? Not sure, but I have several spare shims on hand, and the thickest one is .035" if I recall correctly. So the factory musta been OK with up to .035". If I understand correctly, you'd need .042" to .046" to arrive at the specified .''002 to .006" end clearance? I have needed that much shimming sometimes in the past, and never experienced any related problems.

As for why the clearance changed with new bearings, another possibility is off shore bearings, or brand new bearing versus worn bearings. Hopefully you will let us know if you ever figure it out. But I'd have no problem running .042-.046" of shims. Biggest danger is moving the brake backing plate outward too far, causing interference with the drum lip.

Finally, all the above is based on what I think you mean. You said the problem is," excessive end play", but I think you meant excessive shimming needed to achieve proper end play (.002" to .006"). Is that correct, or am I totally out in left field?

[doofus]

Maybe you had excessive end play before tear down and didn't notice, the axles run against the diff. cross pin. if that is worn you will have to much end play. i have same problem on my 63 but it's a TT rear and needs the thrust buttons replaced, when i do this i will change to correct "Auto Adjust " backing plates. it's an older rear end. check that cross pin before you get to involved. Luck Doofus

[JoeHall]

Maybe you had excessive end play before tear down and didn't notice, the axles run against the diff. cross pin. if that is worn you will have to much end play. i have same problem on my 63 but it's a TT rear and needs the thrust buttons replaced, when i do this i will change to correct "Auto Adjust " backing plates. it's an older rear end. check that cross pin before you get to involved. Luck Doofus

I believe the OP's verbiage is confusing, and has you making the same mistake I did, in thinking of it in reverse. If it has, as he said, "excessive end play" that would mean all shims removed, and still has excessive end play, unless the race is driven below the surface of the axle housing. I believe he means that it requires EXCESSIVE SHIMMING in order to create the specified .002" to .006" of end play. But will wait for him to answer my question above, for clarification.

After sleeping on it, I offer the following (for excessive shimming): insure you install the left axle first, including the backing plate, and torque it down to spec. Then, after slipping the right axle in place, use a brass drift to tap (soundly, several times) on the axle end, in order to drive the left axle's bearing race out fully flush against its backing plate. The tapping sound will change to a thud when the race becomes flush against the backing plate. Often, the first 1-2 taps will sound differently, which means the race was being moved outward. Any outward movement by the left axle race, decreases the total thickness of shims needed on the right side. This MUST be done first.

[Jeffry Cassel]

Right. Pull it out and seat the bearing snugly. re-install and shim to .003 to .005 or 6. Don't get it too tight! Measure slop with a dial indicator. If .040" the select shims .035 or .036 with a micrometer. Put 'em in and close it up.

[Harryhawk]

Joe Hall, thanks again for you time and help. Yes that's what I meant left side all buttoned up the race flush with the flange on the right side and no sims. Now for the good news, problem solved and you eluded to it in post #7 '' off shore bearings'' who would have thought new bearings straight out of the box would be incorrect, inside diameter was wrong there for pressing on to axle to far creating too much end play or should I say movement between the bearings and races. The positive side to all this is that I have a far better understand of the rear axle set up AND don't take things for granted. Once again thanks Joe and to all the other blokes for you input, much appreciated. Cheers Harryhawk

[JoeHall]

Glad you got er figured out. Not much surprises me anymore with offshore stuff. A lot of it is good, especially if it has a legit USA name brand, i.e. ACDelco. But some of it has problems. I once bought a couple of rear axle nuts for Studebaker. They were somewhere between metric and SAE, but not exactly either. I tossed them, and found good OEM ones. Sounds like your bearings were similar to my axle nuts. Agree, you just learned a couple of things in this venture.

Again, glad you got it figured out!

[Jeffry Cassel]

Chinese inches don't always equal American inches.