What Problems With Disc Brakes?

Besides normal wear, a disc brake other things can happen. The three most common are warping, scaring and cracking. Warping of a brake rotor is usually caused by excessive heat. This occurs when the rotor's brake friction area is at a much higher temperature than the inside of the rotor brake. This difference in temperature causes different amounts of expansion within the disc brake with resulting warping. Warping of a disc brake will usually occur when overheating is caused by excessive braking, such as racing or descending hills or mountains. Other causes are "riding" the disc brake or a stuck disc pad, where the brake pad always touches the disc. Minor warping can be correct on a disc brake lathe.

•   Scaring or scoring of your disc brake can take place if the disc brake pads are not changed when worn out. When enough of the brake friction material has worn away, the pad's steel backing plate, if glued, or the pad's retainer rivets, if riveted, will touch the discs surface and make scratches on the disc. If the disc brakes are operating satisfactory, then you can install new brake pads without replacing or resurfacing the rotor. Scored rotors can be cleaned up with a brake lathe, but again they must not be taken down or thinned out beyond the manufactures recommendation.
• Rotor cracking is usually seen only on drilled rotors in a disc brakes. The drilled holes may get small cracks around the outside edges of the holes. This is caused by the rotor's uneven rate of expansion in severe duty environments. This can be on only one rotor. As a general rule, all cross drilled rotors will eventually show small hairline cracks in them, and this is normal. A major crack in the disc brake rotor cannot be repaired and it must be replaced.

•   While we have discussed rotors and pads being replaced at different times, there are some other thoughts on the subject. Some disc brake repair shops believe that it is better and safer to replace each disc and the brake pads at the same time.