Rear Wheel Bearings - How much $$$

[jdoublehcubed]

Tell me if you think this is rear wheel bearings.

In preparation for replacing the front brakes rotors, I thought I would remove my rear brake rotors and have them turned. I had recently noticed a bit of a shudder/vibration coming from the rear during hard braking. I also put my car away just after a wash in December and the rear pads were stuck to the rotors when I got it out, so I thought I had left a deposit which developed into a slight uneven wear (or a warp or something else).

So I got the car up, wheels off, and rear calipers off, and... less than .002 runout. WTF. I also noticed that when spinning the hub/rotor, I felt some scraping/grinding, what I would imaging a failed wheel bearing or perhaps CV joint would feel like.

Replacing wheel bearings on a drive axle is out of my skill range, so I need to call my indy tomorrow and make an appointment. How painful is this going to be?

Also, if you think it could be something else, let me know. Something is causing the brake shudder, its from the rear only (no vibration in steering wheel, only seat), and I really don't think its the rotors.

[gas-can]

Do you hear the bearings when you drive? Especially when you corner? Usually rear wheel bearing going out will start sounding like one of those maglev roller coasters - especially at high way speeds. I would imagine it would be even more pronounced on the zeds cause you are directly sitting on the drive axles...

How many miles on the car?

-gc

[jdoublehcubed]

82k miles.

I haven't noticed any noises from the rear wheels while driving, but I also have RPI mufflers, so...

The shudder seems to be only at decent speeds (at least 40 mph). I can't recall ever feeling the shudder at a low speed, like rolling up to a stop light.

[inTgr8r]

Highly unlikely to be bearings from what you describe

Sounds like pad deposit to me.... Especially considering your frozen pad situation.
You won't detect pad deposit by checking run out.

Easiest way to correct is to run a set of aggressive track pads to grind the surface deposit off.

[jdoublehcubed]

I took the brake calipers off, then spun the rotors and felt/heard the grinding. Also, the rotors felt completely smooth.

Where would the pad deposit be, if not on the rotor or pad? I would think it would have to be on the rotor surface, which should be both visible and show up as runout in that spot.

[gas-can]

Yup, I agree with Intgr8r. Wheel bearings also don't usually go bad so abruptly (unless there was a collision)...


Pad deposit seems to be the prime suspect. You might be able to remove this deposit by re-bedding the pads - in a deserted road with no cops, speed up to 60mph and then brake really hard to around 10 mph - this should be hard, but not so much to activate the ABS. Now speed up again immediately to 60 - repeat this about 10 times in close succession. You will smell the pads and the pedal may go soft. After the 10 times, drive around for about 10 minutes to cool the brakes down. Don't stop anywhere and hold the brakes down during this cool down or you will redeposit the compound.

-gc

[gas-can]

Originally Posted by jdoublehcubed

I took the brake calipers off, then spun the rotors and felt/heard the grinding. Also, the rotors felt completely smooth.

Where would the pad deposit be, if not on the rotor or pad? I would think it would have to be on the rotor surface, which should be both visible and show up as runout in that spot.

Interesting... Was there any play from side to side? (Grip the bearing/wheel at 3 and 9 o'clock - now try to push/pull). There should be no play. Spinning a non drive wheel bearing will usually give a small amount of resistance. If it's really lose, then that's a sign of a bad one as well...

Just to rule out the obvious, the rest of the suspension looks ok, right?

Regarding pad deposits, you would be extremely hard pressed to determine this by touch. The amount of deposit you need to provide a shudder during braking is ridiculously thin. Discs can feel absolutely smooth but shake like a bugger during braking...

I still feel it's the discs. A wheel bearing that's going out will make a noise that will usually steadily increase with speed. It may also disappear/increase when you take corners as the forces redistribute according to the curve. The fact that this also only happens during braking is also a clue.

-gc

[inTgr8r]

Read this....

It's mainly about track use, but still applies.
See the section on imprinting which is likely what you have done. ( but in a different way)

[jdoublehcubed]

OK, you've convinced me that it might be pad deposit. I'll take the rotors off and have them turned to eliminate that possibility. I don't have any race pads to use.

BUT, that doesn't explain the significant grinding/grittyness I feel when spinning the hub/rotor with no caliper installed, so I still think I have a wheel bearing problem unless someone can explain that.

[jdoublehcubed]

My indy says $585 per side in the rear. 4 hours of labor.

[Vanne]

if you are going to tackle the bearings, id sugest aslo doing the bushes while the rear end is apart.

[inTgr8r]

Originally Posted by jdoublehcubed

OK, you've convinced me that it might be pad deposit. I'll take the rotors off and have them turned to eliminate that possibility. I don't have any race pads to use.

BUT, that doesn't explain the significant grinding/grittyness I feel when spinning the hub/rotor with no caliper installed, so I still think I have a wheel bearing problem unless someone can explain that.

sorry I missed that.

[Shipkiller]

How are you going to have your brake rotors turned? A normal brake rotor turning machine will not work on drilled rotors...

[The HACK]

Originally Posted by jdoublehcubed

BUT, that doesn't explain the significant grinding/grittyness I feel when spinning the hub/rotor with no caliper installed, so I still think I have a wheel bearing problem unless someone can explain that.

A bad rear bearing is pretty obvious when you drive. Car would have a low hum or rumble constantly when driven but vary in pitch and intensity with speed, and also will vary in intensity and speed as you load one side or another. You can't miss it.

The spinning rotor/hub and grinding noise can be from a poorly adjusted hand-brake, especially for a car that sat for so long. It's possible that the hand-brake may have rusted onto the hub and left some minor rust deposit (even through the hub is aluminum, the shoe is a metallic compound and the drum is an iron ring inserted into the aluminum hub), and every time the rotor/hub turns the shoe is scrubbing against the high-spot on the ring. Take both rotors off and try and spin the hub by and and see if it still makes that grinding noise. If it still does...You've got other issues to worry about.

[jdoublehcubed]

Originally Posted by The HACK

A bad rear bearing is pretty obvious when you drive. Car would have a low hum or rumble constantly when driven but vary in pitch and intensity with speed, and also will vary in intensity and speed as you load one side or another. You can't miss it.

The spinning rotor/hub and grinding noise can be from a poorly adjusted hand-brake, especially for a car that sat for so long. It's possible that the hand-brake may have rusted onto the hub and left some minor rust deposit (even through the hub is aluminum, the shoe is a metallic compound and the drum is an iron ring inserted into the aluminum hub), and every time the rotor/hub turns the shoe is scrubbing against the high-spot on the ring. Take both rotors off and try and spin the hub by and and see if it still makes that grinding noise. If it still does...You've got other issues to worry about.

I will try that tonight.

I don't know if I would hear the wheel bearing hum over the RPI mufflers, seems unlikely unless it was really screaming.


A lathe should work fine with rotors with holes drilled in them. A lot of shops don't like to do it, but theres nothing about a lathe that makes it inherently unable to cut a disc with holes drilled. It will just make a lot of noise as the cutter passes over the holes.

[StickMon]

^WHS
The noise is the parking brake shoes.
I wouldn't worry about it, as long as the rotor spins free and the hand brake works.

[jdoublehcubed]

Originally Posted by StickMon

^WHS
The noise is the parking brake shoes.
I wouldn't worry about it, as long as the rotor spins free and the hand brake works.

Handbrake works fine. But I'm still back to the original problem, brake shuddering. Could deposits on the parking brake drum cause brake shudder (while applying regular brakes via the caliper)?

[jdoublehcubed]

Originally Posted by Vanne

if you are going to tackle the bearings, id sugest aslo doing the bushes while the rear end is apart.

just the trailing arm bushings, or is there something else that commonly fails thats going to be more accessible?

I don't think the rear end will need to be taken apart nearly far enough to get to (for example) the subframe or diff bushings.

[inTgr8r]

yup... I agree re handbrake.

[inTgr8r]

Originally Posted by jdoublehcubed

Handbrake works fine. But I'm still back to the original problem, brake shuddering. Could deposits on the parking brake drum cause brake shudder (while applying regular brakes via the caliper)?

no.

It would definitely be on the rotors.

one thing you can try instead of track pads to clean is;
use some brake cleaner and a scotch-brite scour pad and clean them up by hand, then go rebed them.
this depends on how badly they are pad stamped from the pad being frozen to the rotor.

do you have any etched pattern that you can see where the pad was frozen? (look closely)

[jdoublehcubed]

Originally Posted by inTgr8r

no.

It would definitely be on the rotors

OK, so I should be able reach a definitive conclusion by
(1) checking the parking brake surfaces for rust/deposit
(2) checking for play in the wheel bearing
(3) having the outside surface of the rotors turned
(4) (if possible) having the parking brake surface turned

If I do all of these things and still have a problem, its a wheel bearing. true? anything other than brake rotor or wheel bearing?

[inTgr8r]

way over-kill.
just clean the rotors and rebed.

(you cant turn these rotors)