Front Wheel Bearing won't go on

[Jokester]

I've done the same mistake twice, I go to put the front wheel bearing on and it won't slide on. I tried putting anti seize on, tried using a hammer and 2x4, nothing works.

I have ruined two sets of bearings and still don't have my front end complete. Both were genuine BMW bearings from fcp euro. The inner race just gets wedged on the shaft and I have to pry off the wheel bearing as it has a ton of play but still rotates easy, effectively ruining them.

I'm fucking pissed as this is supposed to be an easy install for an e30, any help would be greatly appreciated.

[roguetoaster]

First I'd inspect the axle for damage. Then if there isn't any you should in theory be able to slide the bearing on, using the nut to seat it, all without any hammering of any sort.

If you have measuring tools it wouldn't hurt to measure the OD of the axle and the ID of the bearing/hub, just in case they are not correct for some reason.

Worst case if they are slightly off you could reduce the OD of the axle stub as a last resort, but you'd have to be very careful to reduce the OD evenly.

[Jokester]

First I'd inspect the axle for damage. Then if there isn't any you should in theory be able to slide the bearing on, using the nut to seat it, all without any hammering of any sort.

If you have measuring tools it wouldn't hurt to measure the OD of the axle and the ID of the bearing/hub, just in case they are not correct for some reason.

Worst case if they are slightly off you could reduce the OD of the axle stub as a last resort, but you'd have to be very careful to reduce the OD evenly.

there seems to be some deep scratches on the axle, would those cause the issue, does the axle have to be 100% smooth? I attached photos to give a better idea.

Driver (this is the worst one)
Untitled by Joseph Sleeman, on Flickr

Passenger
Untitled by Joseph Sleeman, on Flickr

Untitled by Joseph Sleeman, on Flickr

Untitled by Joseph Sleeman, on Flickr

[e30davie]

I would get some emery paper and clean up the axels. They would need to be perfectly smooth for it to slide on smoothly. And if it gets hung up and you belt it you only make it 10x worse. keep sanding it as even as you can until it slides on by hand. don't touch the hammer!

[ForcedFirebird]

A file works great for the scratches, I've had to work on some mangled spindles in the past years. The bearings probably weren't "ruined" just because they spin easily, the inner halves probably just separated a little, and would go back to normal once bolted in.

If you must use a hammer, use a rubber/plastic dead blow and a piece of pipe or something so you only hit the inner race - but realistically they should go on by hitting them with the palm of your hand.

Also, your dust covers are hosed, replace them. The dents will rub the ABS sensor ring.

[S.J.1981]

I would get some emery paper and clean up the axels. They would need to be perfectly smooth for it to slide on smoothly. And if it gets hung up and you belt it you only make it 10x worse. keep sanding it as even as you can until it slides on by hand. don't touch the hammer!

This is good advice.

Just replaced front and rear bearings, surprisingly the rears came off and went in without any fuss. The driver's side front pulled one of the inner race carrier caps (if that makes sense) just maybe a bit, not enough to cause any play or issues, but im replacing it. Passenger side was a slow and very watchful event to be absolutely sure it is dead straight and not causing problems.

[Jokester]

Measured the axle diameter and the wheel bearing inner diameter. Axle was 30.9mm and the wheel bearing was 30.6mm, not a huge difference at all. Seems like it should go right on but it’s not :/

[E30-325iS]

The axle is 0.3 mm bigger than the bearing so it's not going to go on. It's not like the inner race of the bearing is going to stretch to fit around the axle.
If the axle is 30.9mm, I would expect the inner diameter of the bearing to be 31.0mm.
I'd send the hub back and try to get one from a different manufacturer.
It'll be difficult to remove 0.4mm from the axle evenly. As Roguetoaster said in post 2, you would only consider this as a last resort.

[Jokester]

The axle is 0.3 mm bigger than the bearing so it's not going to go on. It's not like the inner race of the bearing is going to stretch to fit around the axle.
If the axle is 30.9mm, I would expect the inner diameter of the bearing to be 31.0mm.
I'd send the hub back and try to get one from a different manufacturer.
It'll be difficult to remove 0.4mm from the axle evenly. As Roguetoaster said in post 2, you would only consider this as a last resort.

I’ve tried three sets of wheel bearings, two were genuine bmw, the other was junk Meyle. Seems like the only resort is to buy new strut tubes, maybe GC coils :devil:

[steelynorm]

Re:

I just bought some cheap hubs from rock auto.
those bearings would not go on without persuasion.
If I would have read this, I would probably taken some emory paper to my axles.
Instead I took a rubber mallet and a socket to get them on.
torqued it down, pinched down the safety nut and thought it was good.
don't have many miles on it yet, but it sounds and feels better than what was on their previously.


Good luck.

[straight6pwr]

i have also differentially heated the parts to help persuade them.

throw ice packs over the hub and put the bearing in front of a hairdryer for awhile. 80 deg of difference between the two can really help.