A: Loosen the wheel lug nuts, raise the vehicle and support it securely on jackstands. Apply the parking brake. Remove the wheels. Visually inspect the disc surface for score marks and other damage. Light scratches and shallow grooves are normal after use and won't affect brake operation. Deep grooves require disc removal and refinishing by an automotive machine shop. Be sure to check both sides of the disc. To check disc run out, place a dial indicator at a point about 1/2-inch from the outer edge of the disc. Install the lugnuts, with the flat sides facing in, and tighten them securely to hold the disc in place. Set the indicator to zero and turn the disc. The indicator reading should not exceed the run out limit. If it does, the disc should be refinished by an automotive machine shop. If you elect not to have the discs resurfaced, deglaze them with sandpaper or emery cloth. The disc must not be machined to a thickness less than the specified minimum thickness, which is cast into the disc. The disc thickness can be checked with a micrometer. Remove the Brake Caliper (don't disconnect the brake hose) and hang it out of the way. Remove the caliper mounting bracket. Remove the lug nuts installed and pull the disc off the hub. If the disc is held in place by pressed on washer-like retainers, cut them off. Installation is the reverse of removal. Tighten the caliper mounting bracket fasteners to the torque. Lower the vehicle and tighten the wheel lug nuts to the torque.