Rotor Minimum Thickness
Measure rotor thickness at the center of the brake shoe contact surface. Replace the rotor if it is worn below minimum thickness or if machining the rotor will cause its thickness to fall below specifications.
CAUTION:
DO NOT machine (turn) the rotor if it will cause the rotor to fall below minimum thickness.
Minimum thickness specifications are cast on the rotor's unmachined surface (or stamped into the hat section).