General Information

GENERAL INFORMATION
Any servicing of the rotor requires extreme care to maintain the rotor within service tolerances to ensure proper brake action. Before refinishing or refacing a rotor, the disc should be checked and inspected for the following conditions:
^ Braking surface scoring, rust, impregnation of lining material and worn ridges.
^ Excessive lateral runout or wobble. Runout Check
^ Thickness variation (Parallelism). Thickness Variation Check
^ Dishing or distortion (Flatness).

If a vehicle has not been driven for a period of time, the rotor surface will rust in the area not covered by the brake lining and cause noise and chatter when the brakes are applied. Excessive wear and scoring of the rotor can cause temporary improper lining contact if ridges are not removed before installation of new brake pad assemblies. Some discoloration or wear of the rotor surface is normal and does not require resurfacing when linings are replaced. Excessive runout or wobble in a rotor can increase pedal travel due to piston knock back. This will increase guide pin sleeve wear due to tendency of caliper to follow rotor wobble. Thickness variation in a rotor can also result in pedal pulsation, chatter and surge due to variation in brake output. This can also be caused by excessive runout in rotor or hub. Dishing or distortion can be caused by extreme heat and abuse of the brakes.