When the brake pads come in contact with the brake rotor to slow and stop a vehicle, the pressure and friction occasionally cause a vibration that produces a squeaking sound. These squeaks are often normal, but they may also mean that the brakes are starting to wear out.
Brakes typically produce noise when the driver brakes hard or travels in dusty or sandy locations among other reasons. Brand new cars also have fairly unused brakes that may make high-pitched noises. The noise can be minimized or eliminated by using sandpaper to soften brake pad surfaces, applying milk or lotion at the back of the pads or replacing the brake pad with another brand.