Squeaking front wheels (brakes?)

brakes

#1

'93 Toyota Corolla

I’ve taken my car in to the shop twice for a squeaking/twittering noise coming from the front wheels. The first time, they machined the rotors, regreased the system, and rebalanced the front-rear braking. They maintain that there is a hard spot on the pads that is causing the squeaking. Here are the details that I gave to them describing the noise:



* Intermittent ? problem comes and goes.

* Squeaking generally seems to be more frequent and intense after the car has been sitting for at least a few hours ? especially if it has been sitting in the sun.

* Doesn?t squeak constantly ? squeak occurs once per wheel revolution as if there?s a high-spot somewhere.

* With the windows closed, it sounds like a relatively high-pitched squeak (not as high-pitched as worn brake pads though) ? almost like wet rubber on glass.

* With the windows open, it has a more metallic scraping/grinding sound.

* Squeak occurs most often when braking.

* Applying additional pressure to the brake pedal does not change the sound or intensity of the squeak.

* Squeaking will often continue after releasing the brake pedal.

* Squeaking will often occur when going around corners or roundabouts ? even when not braking.

* As far as I remember, the squeaking started last winter, possibly from driving over rough ice.



Reversing while turning and applying the brake lightly (as if backing out of a driveway or parking space) often causes a grinding/scraping/crunching sound. I think that this is the same sound that occurs when braking, but sounds different because the wheels are turning more slowly and in the opposite direction.



When coasting at a constant speed, slightly depressing the accelerator to maintain the current speed causes a squeaking/twittering sound. Depressing the accelerator further so that the car accelerates, or releasing the accelerator causes the squeaking to stop immediately. This noise is most obvious when coasting at about 40 Mph. I don?t know if this is the same squeak that occurs when braking.



The mechanics said that it’s not a safety hazard, but suggested that I get ceramic brake pads to stop the squeaking if I find it annoying.



Does anyone have any other opinions?


#2

Have the vehicle raised off the ground and grip the tires (one at a time) at 3&9 o’clock and shake it back and forth.

Then do the same at 12 & 6. If there is a little play, the wheel bearings MAY need to be changed.


#3

Thanks for the reply. By shake back and forth I assume you mean towards and away from the car, not in the direction of wheel rotation (?). Can this be done one wheel at a time using the jack, or does the car need to be up on a lift?


#4

BTW, the car only has ~86,000 miles on it. I found some additional information here: http://en.wikipedia.org/wiki/Wheel_bearing

This sounds like it may be a possibility, but the noise usually only occurs when I’m braking. This could be an explanation for the accelerator-induced noise. I’ll perform the wheel bearing test to see if I can notice any play.