Replaced rear wheel bearing, hub still wobbles

[E30 Wagen]

When I was swapping trailing arms, I had a friend press new wheel bearings in. But, then I made a stupid mistake and I thought I may have accidentally ruined the passenger side bearing with a torch. I could wiggle the hub very easily with my hands.

But, after pressing the new bearing in it still wobbles just the same and now I feel like an idiot for ruining two bearings which were likely fine. What could possibly be going on? Could the trailing arm hole be too big, which is allowing some play? Yet I can't really see the outer race moving, only the inner. I had no difficulty pressing the new bearing in.

[jlevie]

Were these OE or OEM bearings? If they were then I'd suspect a problem when pressing the bearing in and then pressing the hub in. When pressing the bearing into the trailing arm pressure must only be applied to the outer race. When pressing in the hub only the inner race must be supported.

I use a Sir Tools B90 kit for this which has the appropriate "pressure plate" for each operation.

[E30 Wagen]

I was able to press the bearing in while only putting pressure on the outer race. I didn't know about having to support the inner when pressing in the hub though. The bearings were both new FAG brand. I'm also using a SiR kit

[E30 Wagen]

Any other thoughts on this before I start working on it again tomorrow? Did I damage the bearing by not supporting the inner race when pressing the hub in?

[TobyB]

This is without the halfshaft in? I vaguely recall that mine were a bit wobbly
before I pulled the halfshaft, then they were nice and tight.
The flange only
goes into the outer race, and without the shaft going through it and clamping the
whole mess together, the only thing holding the flange in place is the
outer dust shield...
... but hell, that was 4+ years ago, and I haven't done one since. So I'm just another internet doofus...

t

[jlevie]

This is without the halfshaft in? I vaguely recall that mine were a bit wobbly
before I pulled the halfshaft, then they were nice and tight.
The flange only
goes into the outer race, and without the shaft going through it and clamping the
whole mess together, the only thing holding the flange in place is the
outer dust shield...
... but hell, that was 4+ years ago, and I haven't done one since. So I'm just another internet doofus...

No you aren't an "internet doofus" and you have a good point. Until the half shaft is in the bearing isn't loaded and could wobble.

[E30 Wagen]

It wobbles with the half shaft out.

What do you mean about the bearing being "loaded"? It shouldn't matter if the half shaft is in or not. Once the bearing and hub are pressed in, there should be zero play in the hub. I was getting like 5* wobble in all directions.

[wilholl]

Any other thoughts on this before I start working on it again tomorrow? Did I damage the bearing by not supporting the inner race when pressing the hub in?

Yes, do not press the hub into the bearing without supporting the inner race!

Get this kit... It works great and made the job very easy for me.

http://www.harborfreight.com/fwd-front-wheel-bearing-adapters-66829.html

Got mine on sale for $79 and I did not have to buy the expensive $$$$ tool and did not have to make my own like some have done.
Not knocking those who have found a different way to do it, some have been really clever!
This is what worked best for me.

[E30 Wagen]

Did the job again today, and was concerned after pressing in the new bearing that I could still wiggle the inner races quite a bit. Apparently this is normal so i pressed in the hub anyway, this time supporting the inner race. Not supporting the inner race must have been the mistake I made since now there's zero play. Lesson learned I guess.

Also realizing i should have posted this in the suspension section, oops

[TobyB]

It shouldn't matter if the half shaft is in or not.

...but it does. The E30 rear is a dual row ball bearing, with 1 outer race and 2 'split' inner races.
But neither inner race is positively retained by the balls. heh, heh....
They're just half- races, with no 'wrap' past 90 degrees.
There's a name for that in the bearing world, but I forget what it is...

So if you don't have the halfshaft and the hub sandwiching the inner races together, they
are only held from falling out by the dust shields- this is why you can rip one apart by
disassembling or assembling it in the wrong order (he learned, the expensive way).

So you can push IN on the inner races, but not pull OUT on them, IF the halfshaft's
not in there. (If it is, it transfers load to whichever race is against its balls, and everything's fine.)
And that's also why the inner race always comes out on the hub when you go to
replace one- the hub- side inner race has no resistance to 'pull', only push, and the
hub's a light interference fit with the bearing.

Yeah, semantics mostly, but it explains the 'why' for supporting the inner race when pulling
the whole mess together.

And why you got wobble...

t

[ahlem]

Save your old bearing races to use to press in the new bearings next time. They are also handy for other similar projects. The loose ball bearings can also be good for stress relief toys and wrist rocket ammo.