Brake rotor, pad, or hub bearing problem (or some combo of the three)?
 

There are mysterious, metal-on-metal, dull rubbing sounds (not squeals) coming from my wheels. I suspect brake pads dragging, drums worn out, hub bearings, and would love input.

Lifted on a jack, the rear wheels will spin but will turn only a few times, for under ten seconds. The front wheels hardly spin more than one or two turns, a total of one or two seconds. The brake pads seem engaged slightly on the back wheels, indicated a dull metal rubbing sound, like shuffling shoes on sandy floors (bearings?). That sound seemed more pronounced in the front wheels.

Any help greatly appreciated. I'm worried the front could be transmission-related.

james

The easiest way to figure out what is wrong is with your hand, CAREFULLY. Whatever is the hottest is your culprit.

Thank you, Daox. I tried that test this morning on each of two 6 mile legs of a mornign trip. Here is a report back. The front brake calipers were not really notably different in temp. But the discs were, though just slightly. It was hard to tell, but the front driver side disc was hotter. That wheel also spun slightly less freely than the passenger side front wheel in my test yesterday. This could be warping of the disc? Uneven wear on the pads? I looked up in the shop manual and online how to disassemble and inspect. I'll do that. But if you or anyone else has tips... thanks!

Your rotor may be warped.
Take your wheel off and spin it and try to see what is rubbing on what.
High heat can cause the rotors to warp.
1 more maybe even more common problem would be the caliper is sticking / needs to be honed out and a rebuild kit put in. They can be if not pitted honed out with emery cloth and reused. Most people just buy new ones.

Drums or disks in the back?

The rears should spin freely longer than that. Here in the Rust Belt, parking brake cables corrode stuck especially if they aren't used daily. A hung-up parking brake cable could prevent full release of the shoes on rear drums, or the special parking brake shoes or pads on disk brake cars.

If the pedal isn't pulsating when you brake, the rotors are probably not warped.

Jack it up again, pull the wheels, inspect the rotors, pads, and if present drums and shoes. Scoring on the rotors and/or drums (if bad enough) indicates a need for resurfacing or replacing them. Thin/gone/unevenly worn pads/shoes should be replaced. Calipers should be free to slide back and forth on their guides. Flexy brake lines shouldn't be cracked, their brackets shouldn't have really heavy corrosion; hard brake lines shouldn't be badly rusted. If one goes that far they may as well pull the pistons outta the calipers for inspection of the bore, piston, and seals. Same with wheel cylinders in the rear for drum brakes.

It's usually a filthy job but someone's gotta do it.

do you have a manual transmission? the input shaft bearing will growl as it gets old also and i don't mean the throw out bearing. have you lifted the front and physically tried to wiggle the wheels in and out from the top or sides? if they do, try to look behind the wheel and see where the play is coming from.

Hi guys, thanks. @ Frank: they are drums in the rear, Frank, and rotor/discs up front. The brakes work well, actually. No pulsing like you describe, Frank. Just a rubbing sound that increases with the speed of the wheels, not with RPM. And I noticed it changes a little when I steer, louder or much softer. Thanks for the description of the service procedures too. I suspect I'll need it. And thanks scivicblu83 for the test description. I'll try that today and report back.

The brake pads will make a noise when they get down to the minimum spec and the noise is like what you are describing. if the rotor is well worn it will have a ridge on the outer edge that can also cause the noise you describe.

The fron calipers are of the floating type, if the pins the caliper "floats" on are corroded then the caliper will not float properly. It usually causes the pads to wear unevenly.

Pretty sure the rear stub axles are sealed bearing units, so there is not much you can do there except to replace them when you get a bearing noise, but they last a long time.

It may also be an accumulation of brake dust in the rear brakes.

A good 4 wheel inspection is your best bet. If the rears have a lot of dust and a ridge on the rear drum, you should clean and deridge the drum, and replace the shoes if necessary.

Fronts, you should remove the hydraulic portion of the caliper (leave the hose connected). Check the pads and replace as necessary, turn- replace the rotors if necessary. When you compress the caliper piston make sure it is not binding, and lubricate the pins the caliper slides on to make sure it can move easily.

regards
Mech

James-
The curiosity of your question/issue and the wheel roll/spin made me think how well my wheels spin/roll freely. So I was in the garage, with a camera and made you a film! Since my car is the same series and a little older, I thought it would be a decent comparison.


http://www.youtube.com/watch?v=r25xShdxRNU

As you can see, I feel that Frank is correct something is sticking with your rear brakes, I discontinued using my e-brake a couple months ago as it would stick at times.. upon release. Maybe something similar has occurred?

Hope this helps.

-Dave

Front brakes have maybe 8K on them, and much more on the rear.

These too are great responses. Many thanks! I was out of town yesterday with a friend at the junkyards. In the afternoon had "Black and Green" on jack stands and did some inspection of the front hubs and half-axles. (I had not read these newer responses yet, unfortunately.) But during inspection I saw that there really is no play in the front wheels that might suggest a hub bearing problem, but the hub, without the wheel on, did not make the grinding noise at low RPM in first gear (I wish I had tested at higher RPMs... forgot). Other things showed themselves: the CV boot on the passenger side half-axle is showing wear and there's a little grease leaking from the boot. The steering arm thing on the driver side is also leaking a little grease (nothing alarming in either case, but I'm gonna start collecting tools and reading-up on how to DIY replace the half axles with new).

That video is VERY helpful too. Big contrasts with my wheels.

So I'll get to these inspections today, after quality time with the family, and report back here.

Cheers!