How to Check the Rotor, Caliper and Wear Indicator

Your car braking system is one of the most important components of your vehicle's safety. Proper inspection and maintenance are essential. With a little knowledge and a few tools you can check the rotor, caliper and wear indicator to ensure the safety of your braking system.

  • Loosen the wheel lug nuts and raise the vehicle on a set of jack stands. Remove the wheel and reinstall the lug nuts to hold the rotor, or disc, in place. Remove the caliper. After removing the caliper mounting pins, suspend the caliper with a piece of wire, out of the way. Do not let the caliper hang by the hose and ensure the hose is not twisted or crimped.

  • Visually check the rotor, or disc, surface for scoring or other damage. If there is deep scoring or grooving on the rotor, or disc, it will probably need to be replaced. Be sure to check both sides of the rotor, or disc, for damage. Check the wheel bearings to ensure they are properly installed.

  • Check the rotor, or disc, run out. This can be done with a dial indicator placed a half inch from the edge of the rotor, or disc. Set the indicator to zero and turn the rotor, or disc. It should not exceed the allowable run out time as indicated in your vehicle's manual. If it does, it should be resurfaced by a machine shop.

  • Notice the wear indicator located on the base of the caliper. This is a window that shows the wear on your brake pads. Note how close the wear indicator is to the rotor, or disc, indicating the brakes need changes.

  • Inspect the brake hose for leaking, damage, cracks or other problems. If there are problems, replace the hose. If not, leave as is and make a note to check again at your next brake inspection.