Brake Rotor Damage

Disc brake rotors are exposed to the elements and must also withstand the extreme forces and temperatures generated during braking. As a result, they are susceptible to damage.

Rust and Corrosion

Rotors are made from cast iron, which rusts. This is generally rubbed off the friction surface during braking. Under extreme conditions, or if the vehicle is left idle for an extended period, severe rust can damage the rotor.

Warping

Rotor warping is usually caused by improper tightening of the lug nuts, which puts uneven stresses on the rotor. In extreme cases, a rotor can be warped by the extreme heat generated during severe braking.

Cracking

The stresses generated in braking can cause rotors to crack. This is normally associated with poorly manufactured rotors or long worn out rotors.

Scoring

Sometimes, a piece of grit can become lodged in the pad, and this can wear a deep groove, or score, into the rotor. Grooves deeper than 0.06 inches are generally considered too deep, requiring rotor resurfacing or replacement.

Heat Checking

Heat from extreme braking sometimes causes areas of the rotor to become brittle and hard. This is known as heat checking. Low-quality disks made from poor quality cast iron are particularly susceptible.