Haynes Tech Tips - Brake Squeal
You’ve probably heard this before. You (or the guy next to you) brake to a stop with an annoying high-pitched squeal coming from the front of the car. The cause of this noise can be a few things, but usually it’s because of direct metal-to-metal contact between the brake pad back- ing plates and the caliper frame and/or piston. This results in a high-frequency vibration, which causes the accompanying squealing sound.
The fix is fairly easy and inexpensive, although the brakes will have to be disassembled. A special anti-squeal compound is available at auto parts stores. Apply some of it to the back of each brake pad, allow it to set up for a few minutes and then reassemble the brakes.
Be sure to use this whenever you do a brake job yourself, and talk to your mechanic about it if you are having the work done by a garage.