The manufacturer may have installed a thin plate with a small V-notch pointing to one of the wheel studs between the disc and the hub flange to correct disc runout. Before removing the plate, mark the stud that the V-notch points to. If the disc is to be machined or replaced, the plate can potentially be removed and discarded. Check the disc runout on the machined or replacement disc with the plate and disc installed; if excessive runout is present, remove the plate and check again. Begin by loosening the wheel lug nuts, raising the vehicle, and securely supporting it on jackstands before removing the wheel. Next, remove the brake caliper without disconnecting the brake hose, and suspend it out of the way with wire, ensuring the hose is not stretched or twisted. Reinstall three inverted lug nuts to hold the disc against the hub, possibly using washers to take up space. Visually inspect the disc surface for score marks, cracks, and other damage; while light scratches and shallow grooves are normal, deep score marks or cracks may necessitate refinishing or replacement. If pulsating occurs during brake application, suspect disc runout. Common symptoms of damaged or worn brake discs include pulsation in the brake pedal or loud grinding noises from severely worn
Brake Pads, indicating potential replacement. To check disc runout, place a dial indicator about 1/2-inch from the outer edge of the disc, set it to zero, and turn the disc; a reading exceeding 0.003 of an inch may require refinishing or replacement. The disc must not be machined below the specified minimum refinish thickness, which is cast into the disc; use a micrometer to measure thickness. Remove the caliper mounting bracket, mark the disc in relation to the hub for proper reinstallation, and then remove the disc, cutting off any wave washers if present. Clean the hub flange and inside of the brake disc thoroughly before installing the disc onto the hub assembly. Install the caliper mounting bracket and tighten the bolts, then place the caliper over the disc and onto the bracket, securing it with mounting bolts. Finally, install the wheel, lower the vehicle, torque the lug nuts, and depress the brake pedal a few times to bring the brake pads into contact with the rotor, checking the operation of the brakes thoroughly before normal use.