Re: What causes brakes to squeak?
The squealing noise doesn't come from the pads rubbing on the disc as such, but more of a result of the action. If it came from pad material rubbing on the disc it would do it all the time. The noise comes from the metal on metal contact between the caliper piston and the brake pad backing. It can also be caused by the metal on metal contact between the metal of the pad and where it slides, sits or is retained in the caliper body. Ever heard the noise a non lubricated wheel nut can make when tightening a standard wheel? Or even a rusted bolt or nut your trying to undo? A rusted gate hinge perhaps? Put any metal to metal contact under high pressure, throw in a vigorous back and forth movement and bingo, a hideous high pitched squeak, squeal or squealing. From experience, Rubber back pads almost never seem to squeal.