Thickness Variation Check
Check thickness variation by measuring the rotor thickness at four or more points around the circumference of the rotor. Use a micrometer calibrated in ten-thousands of an inch. Make all measurements at the same distance in from the edge of the rotor. A rotor measuring thicker than .0005" (.013 mm) can cause pedal pulsation and/or front end vibration during brake applications. A rotor like this should be refinished or replaced.