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Ok,

Before I go any further on the rear axle, I need to understand something. Are bearing cups supposed to be flush with the housing flange, or are they supposed to have some play to slide in and out? There is really nothing in the service manual that describes this. Are they supposed to be greased on the outside where they contact the housing? Is it supposed to be partially inserted, and drawn down into place when the backplates are tightened? I checked the manuals from 50-56 and they just say to insert the bearing cup, then shims and backing plate, but dont describe anything further.

Also I noticed the shim stack on each side was different. So I imagine whomever was in there previously did not do something right. So I want to recheck the end play. But I want to make sure I understand how the bearing cups are reinstalled first.

Different # of shims of each side is of no significance and is typical of factory assembly, depending on how axle shaft end play was orignally adjusted.

The cups (races) must fit tightly! If they don't, then you should stake the inside of the housing so they will. The races must NOT rotate within the housing.

You only grease where there is motion, there is no motion between the exterior edge of the race and the backing plate, so no grease. Just grease where the rollers contact the cup.

You add/substract shims between the backing plate and the axle housing to obtain the correct axle shaft end play. You can estimate it by feel; if you feel motion but can't see it, it's probably about 0.001. If you feel motion and just barely see it, it's probably about .002 or .003.

But better to make a simple tool to measure that will position a threaded bolt against the end of the axle shaft; a couple of right-angle bends on some steel stock with one end bolted to the axle housing and the other threaded for the bolt. Pull the axle shaft out, contact the bolt against the end of the shaft, tap the shaft in, and measure the resulting end-play with feeler gauges. Wish I had a picture.

So is the cup partially inserted into the housing, and then pressed into place when the backing plate is bolted down?

Not quite as O-D described but could make something similar.

https://packardinfo.com/xoops/html/modules/newbb/viewtopic.php?post_id=17905#forumpost17905

when i put mine in they were tight. i had to tap them in place going around in a circle with my hammer. they are pretty much flush with the axle carrier. i used a small piece of wood to help soften the blow. i greased on the outside a bit as it pretty much gets all over the place when inserting. i put the axle in first with the well greased bearing and then slide the race over it. kinda hard not to get some grease on the outside of the race. i test it and it move smoothly and the race stays in play fine.

take a look at my blog...you can see pics of my race in place on the driver's side. just did the passenger's tonight. easy as 123.

Hank

Well I seated the cup flush with the face also. But what I am hearing is that the cup actually needs to be pulled back a bit so it sits flush against the back on the backing plate when bolted down. That is why the shims are there to allow it to come back enough until the correct end play is achieved. If it was supposed to be flush against the housing flange, then there would be no reason for the shims.

Or am I wrong?

This is what the shop manual fails to explain.

Are there any shims between the backing plate and the axle flange?????? Such shims would be shaped like the axle flange but with a centre hole big enuf to allow the race to protrude thru it a little bit.

Ring shaped shims inserted into the axle housing BEFORE the bearing race is installed would be there to keep the race tite against the backing plate and to keep race from moving back and forth in the bore of the axle.

I'll try to look at Cli55er pictures.

If u don't feel comfortable checking end play by 'feel' then u can buy a Dial Indicator. Get the magnetic base with it. Very useful and universal application precision measuring tool. Cheap ones start at about $20 at 1-800-use-enco. Tell them to send a free cataloug wheather u buy anything or not. Great cataloug.

" ... the cup actually needs to be pulled back a bit so it sits flush against the back on the backing plate when bolted down. "

This leads me to believe that the cup is recessing into the axle housing deeper than flush with the end of the axle housing??????

Take the new cup (if it's a new cup) and lay it flat on a flat smooth surface. Palce the ORIGINAL cup u removed next to it. Place a streight edge over the top of them to see if the new cup is thinner than the original cup u removed.

look.....maybe i am a dumbass....or maybe i am just following the KISS method....but once i put the shims and backing plate on the thing...then tug the end of the shaft to get it to sit next to the backing plate....etc etc.......see where i am going with this.

seriously if you took it apart carefully and put it back the same way, especially if you didn't change the bearing or race like me, then it should all just go back the way it was when you took it apart. i don't know why this has to be so difficult. not trying to be a jerk and i really appreciate all the discussion, but really....i just don't see why this has to be so hard.

on my z3 i replaced the rear diff.....put it back together the way i took it apart and i have had 0, count them....0 problems since and it has 320 hp and 300 dynoed ft lbs trq. it has axles and shims too....it really isn't that hard. just put it back the way you found it. i have had nearly 10k miles since then...no problems. (apples and oranges i know, but it is still a rear diff)

now if i was to replace the bearing, etc...then i would be a bit more worried about it.

see you on the road, several thousand miles later......and i bet mine will still be going.

flame suit on.....okay now give it to me!

later,

Hank