Regular visual brake checks will prevent your rotor from getting damaged.
Brake pad manufacturers include an indicator that produces a high-pitched squealing sound when it is time to change your brake pads. You cannot always rely on this signal as you may not always be able to hear it. If you wait too long, your rotors will be damaged by the exposed metal scraping against it. Regular visual checks on the thickness of your brake pads will ensure that your brake pads are replaced as needed.
1. Move and park your car in a shady area. Set your parking brake and place a large rock behind each of the two rear wheels to prevent your car from rolling.
2. Loosen the lug nuts on one of the front tires with the tire iron that comes with most cars. The tire iron is the metal rod that has a lug socket on its ends. Remove any hubcaps, if necessary, to reach the lug nuts. Loosen the lug nuts just enough for them to be easy to remove completely but don’t remove them completely.
3. Place your jack under your car directly behind the front wheel whose lug nuts you have just loosened. You want the jack to hoist up that wheel by lifting up the car frame and not something that can be damaged by the jack. Follow the manufacturer’s instructions for your brand of jack to hoist up the car and free the wheel from the ground.
4. Remove the lug nuts and the wheel. Your brake pad and rotor for that wheel should now be clearly visible. The brake pad is part of the caliper that is next to the rotor. The rotor is the big, round, shiny metal piece that you see.
5. Measure the pad width using a ruler. The pad will be the portion of the brake caliper that is between the metal part and the rotor. According to Edmunds, if your brake pads are under 0.25 inches, you need to replace them soon. If they are under 0.125 inches, then you need to replace them immediately or as soon as possible before your rotor starts getting damage. These are general guidelines and your particular brand of brake pad may have slightly differing guidelines.
6. Replace the wheel and the lug nuts. Lower the car to the ground and tighten the lug nuts completely. Replace any hubcaps that were removed. Repeat the above steps for the other front wheel.