Cracked rotors may be caused by mishandling, brake balance issues, wear beyond the minimum allowable thickness, or driver abuse. If a crack extends through a section of the rotor, the rotor should be replaced. If a crack is found on the mounting section of the rotor, the rotor should be replaced. Figure 4 shows a cracked rotor that should be replaced. The crack in figure 5 is
acceptable to run, but the rotor should be inspected on a regular basis to ensure that the crack has not progressed.