Why Would My Breaks on My Car Squeak?

Squeaking brakes can occur for a variety of reaons, including hardening of brake pad surfaces, the composition of the brake pad material, or loose or missing brake parts. An expert mechanic should be consulted to diagnose the problem properly.

Brake Pad Hardening

A brake pad may develop a hard surface, called "glazing," or the entire brake pad may become hard, known as "crystallization." Either condition can cause a squeaking noise. Glazing and crystallization result from frequent or sudden braking while applying large amounts of force (abusively), or when braking in conditions that are especially sandy or humid.

Semi-Metallic Brakes

In 1989, the United States Environmental Protection Agency (US EPA) placed a ban on original equipment manufacturer (OEM) and aftermarket brake pads containing asbestos. Although the ban was reversed, most car manufacturers had already gone through the process of replacing asbestos brake pads with semi-metallic brake pads. Semi-metallic brake pads contain layers of metal slivers, have better stopping power and generally last longer. However, when the metal slivers on the semi-metallic brake pads press against each side of the metal brake rotor, a jaw-clenching high-pitched sound is common (and expected).

Loose or Missing Brake Parts

Squeaky brakes are associated commonly with overlooked or overdue maintenance issues. Possible causes of squeaky brakes include loose brake pads, missing anti-rattle clips or springs, insufficient silicone on the back of the brake pad or resurfaced rotors that are not smooth.