Inspect the brake linings at regular intervals, and any time the wheels are removed (tire rotation, etc.) The outer shoe has a wear sensor which makes noise when the linings wear to the point of requiring lining replacement.

When any lining thickness is worn to within 0.76 mm (1/32 inch) of the shoe or rivet, replace the shoe and lining assemblies in axle sets.

When inspecting the disc brakes, check both ends of the outer shoe and lining by looking in at each end of the caliper. These points are where the highest rate of wear normally occurs. Also, check the inner shoe lining to make sure that it has not worn prematurely. Look down through the hole in the top of the caliper to view the inner shoe. Some inboard shoe and linings have a thermal layer against the shoe, integrally molded with the lining. Do not confuse this extra layer with uneven inboard-outboard lining wear.