When Should I Turn Brake Rotors?

Disc brake-equipped automobiles have brake rotors, or discs. Some vehicles are equipped with front disc brakes and rear drum brakes, and others have four-wheel disc brakes. A few simple methods can be used to check whether rotors need to be replaced.

Initial Checks

Deciding whether to turn or replace rotors isn't always easy, but If pressing down on the brake pedal causes you to feel a rhythmic pulsation of the brake pedal, it is likely that the brake rotors are warped and need to be turned or replaced. Rotors might also require turning if the vehicle has gone unused for an extended period of time.

Measure the Rotor

The only way to know for sure whether the rotors can be turned, or if they should be replaced, is by using a micrometer to measure the thickness of the rotor. With the tire removed and the vehicle safely supported by jackstands, remove the brake caliper and measure the thickness of the rotor in the area where the caliper affixed. Check the manufacturers specifications for the minimum rotor thickness, and don't turn the rotor if doing so would make the rotor thinner than the factory-specified minimum. In that case, replace the rotor instead. Also, look at the rotor carefully because many rotors have the specification cast into the rotor hub. Some automakers suggest replacing the rotors every time the brake pads are replaced and do not recommend ever turning the rotors.