What are the signs of failing wheel bearings?

[TheOtherLeft]

Hiya all,

What are the signs of failing wheel bearings?

Earlier in the week I replaced my front brake pads and rotated my tyres. Since then I have a whurring sound at speed, both coasting and accelerating and at all speeds above 40km/h.

The brakes appear to be fine and are not dragging when driving (it steers straight) or braking (when hard braking it stops straight).

Now my front tyres were quite worn and the rears still had square shoulders. The newer ones are now on the front. Could the whurring noise be from the square shoulders?

After driving for about an hour on the highway both my free qheeling hubs are hot to touch (maybe 60 degreees). I can't smell hot brakes.

Other then the whurring sound my car drives fine.

How do I check the wheel bearings?

Thanks.

[MrGrim]

jack up axel loosen brake shoes pry away from disc a little then try to jiggle wheel up n down the should be no movement

[GaryP]

You will feel the movement without backing off the disc pads. Give them a spin they should run freely. When my last set of bearings were on the way out I would hear a squeal when going straight ahead and the squeal would dissapear when the brakes were applied or the steering wheel was turned. It could also be your tyres as you suggested, an easy way to check would be to rotate the tyres again and see if that makes a difference. My hubs are warm/hot to the touch when driving as well , you will find this is common with a lot of vehicles

[DamTriton]

I would be putting the tyres back the way they were for comparison in the first instance.

Wheelbearing noise is not usually continuous early on, more an intermittent whirring as it is usually only a couple of the balls/rollers and one area of the bearing surface that are shot (ie "hammered down" damaging 1/4" of bearing surface and a couple of the surrounding balls, noise will be most apparent when all thing line up again.).

Good way to tell what it is would be by the number of wheel revs per "whirr". Tyres will be a definite 1:1 ratio, and bearings will will be ~3 revs to one whirr.

[chimpboy]

The timing strongly suggests that it's more likely to be something you did when changing the pads etc than it is to be the wheel bearings.

[chris_stoffa]

What are the signs of failing wheel bearings?
Thanks.

A very obvious sign for me one night was a bright glowing around and under the trailer and a very, very tilted wheel
Lucky it happened in Broken Hill and not somewhere on the Yunta to Arkaroola Rd

Two days later got home

[TheOtherLeft]

Thanks for the tips so far fellas.

Is it still necessary to bed new brake pads in? The Bendix box said it's not needed so I didn't. The last time I installed Bendix 4WD pads I bedded them in (a dozen hard stops from 80km/h) but not this time. I didn't machine the discs either as they were relatively smooth.

[poppywhite]

Tend to agree with chimp boy here.
Also it is good maintance practice to regreace the bearings regularly as they cop a bit of abuse and grease is a consumable lubricant.

[thehanko]

Its fairly normal for hubs to get warm, but if they are too hot to keep your hand on comfortably then I would be pulling the beerings down.

But I also agree that its likely be the brakes or tyres as they were just changed.

if you swap the tyre back it will eliminate that possible reason and reduce the options down to brakes and bearings.

[TheOtherLeft]

Thanks for the tips.

I changed the tyres back and the noise is still there so it's definitely not the tyres.

I pulled the pads out and found this very unusual wear.
Left outside pad:


Right pads (with flash)


Right pads (no flash):


The gouge looks pretty bad in the pic with no flash but it's actually somewhere in between the flash and no flash pic.

What's with the wear on the inside of the pad? When I compressed the piston I used both old pads on the piston and a G clamp to push it back in. It appeared to go back in smoothly and squarly.

Spinning the right hub:
http://flic.kr/p/8X1jpB
http://flic.kr/p/8X4kwC

It appears quite noisy. Is this a bearing problem.

After I put it all back together and drove it, it still had the whurring noise but it still brakes straight and there doesn't appear to be any brake drag at all.

It's got me stumped.

[DamTriton]

Asymmetric wear is usually caused by the caliper pins not being lubricated (and occasionally bent as a result of this). Give them a bit of high temp (lithium based) grease.

Possibility that this has also caused undue pressure on the bearings causing them to collapse, may be simple coincidence that all things happened together when you were doing your wheel change.

Bearing does not sound healthy. Is the preload set OK?

[TheOtherLeft]

Asymmetric wear is usually caused by the caliper pins not being lubricated. Give them a bit of high temp (lithium based) grease.

Possibility that this has also caused undue pressure on the bearings causing them to collapse, may be simple coincidence that all things happened together when you were doing your wheel change.

Bearing does not sound healthy. Is the preload set OK?

When I installed the pads the first time I checked the caliper pins and they appeared OK so I didn't bother with any grease. Maybe I need to put some just to be sure.

I've never touched the bearings so not sure about the preload.

[drr]

Did you replace or machine the discs when you installed the new pads? Looks as if the disc thickness isn't uniform causing the uneven pad wear.
Whirring noise sounds as if it is tyres. Get an alignment, the toe might be a bit out of whack.

[MrGrim]

those wheel bearings are DRY ! watched your flicker vid's

i just spun an old diff i have thats stuffed and the bearings are dry sounds the same "bearing is dry sounds amplified through the disc cover "