Look for rust buildup on the back side of the rotor. If the rotor appears dull gray and rough, look closer at the inside pad. They can wear unevenly so one end looks fine and the other end is grinding metal-on-metal.
Does the car have anti-lock brakes? If so, could you be hearing the hydraulic control unit activating?
Saturday, March 20th, 2010 AT 3:24 PM