What Makes Car Brakes Squeal?

A car’s braking system stops or slows the motion of the vehicle. This braking system can experience problems resulting in a noise audible to the driver when the brakes are applied, called brake squealing.

Causes

  • Brake squealing can be produced by resonance instability, or vibrations between brake pads and discs. Dust, oil or other elements can accumulate in the brake rotors, which can also cause brake squeal. Lining wear indicators, which take the form of either an external sensor or semimetallic layer located in the brake pads, squeal when the brake lining wears down.

Results

  • Some causes of brake squealing, such as dusty brake and resonance instability, do not negatively impact braking performance. Worn-down brake linings cause the brake pads to deteriorate down to their backing plate, eat grooves in the rotor, and may ultimately lead to brake failure.

Remedies

  • Resonance instability that causes squealing brakes can be remedied by greasing the contact between the brake pads and caliper or by adding bonding insulators to the pad backplate. Common brake cleaning products can often remove dust or other contaminants that can lead to buildup on the rotors. Replacing the brake pad at the first indication of lining wear will often solve brake squealing problems.