2000 Explorer squeaks

If the noise is there only when moving, double check the brake sensor. It could be bent and rubbing the rotor. Also, check to make sure the backing plate behind the rotor isn't bent or rusted and rubbing the rotor. If the sound changes when you turn, check wheel / hub bearings. If the noise is only heard when bouncing over bumps, check sway bar bushings, ball joints, shock mounts.

Causes of brake squeal include:
* Vibration is the source of most brake noise. When noise is heard it is usually due to the vibration between the pad and the rotor, or failure in other brake hardware. Hardware should be replaced with every brake job.
* A noise may also be heard if brake †wear’ indicators or †sensors’ touch the disc brake rotor. When this occurs the †sensor’ often emits a high pitch noise to alert that brakes need immediate attention. If this occurs have the brakes checked immediately by a certified brake system specialist.

If your brakes squeal when you don’t have your foot on the pedal:
* It is possible the wear indicator is contacting the rotor because the linings are too thin. It could be time to change your brakes.
* Caliper slide pins that are not properly lubricated may bind causing brake drag. Also, corroded brake hardware and/or bracket will cause brake drag as well.

If you hear grinding sounds when you apply the brakes:
* The most common cause for this condition is when the lining has worn past its service limit and the metal plate is contacting the rotor.
* Some drivers may experience a grinding noise only when the pedal is slightly applied and the vehicle is moving very slow (such as slightly releasing the pedal from a stop position). This operation is normal.