Brake Rotor Thickness Variation Check
THICKNESS VARIATION CHECKCheck thickness variation by measuring the rotor thickness at four or more points around the rotor's circumference. Use a micrometer calibrated in ten-thousandths of an inch, and make all measurements at the same distance in from the edge of the rotor.
A rotor which varies in thickness by more than 0.013 mm (0.0005 inch) can cause pedal pulsation and/or front end vibration during braking, and thus should be refinished to specifications, or replaced.