Disc brake service begins by removing a small amount of fluid from the master cylinder. Next, using use a C-Clamp, push the caliper piston back into the bore. This will let the pads clear the ridge of rust that accumulates on the edge of the rotor. It also provides room for the new pads during reassembly. If you find yourself working on a vehicle with fixed calipers, you'll do this step after the caliper has been removed. Once the piston has been pushed back into the bore, unbolt the caliper, but don't loosen the brake hose fitting. Instead, remove the caliper from the spindle and hang it out of the way using a piece of wire or a bungee cord. Next, remove the pads and inspect them for wear and damage. Measure the pad friction material at its thinnest point. If the pads are 2/32 inch thick or less, they should be replaced. Uneven pad wear often means that the caliper is sticking and not providing equal pressure to both pads. Pads with excessive wear or cracks should be replaced. Then inspect the caliper for fluid leaks, and check the dust boot for cracks or damage. If the piston seal is leaking, the caliper will have to be rebuilt or replaced. Check the caliper mounting slides for rust and proper lubrication. Next, check the rotor. If it's scored, shows signs of overheating, or does not meet the manufacturer's thickness and runout specifications, it should be machined or replaced. Many manufacturers don't recommend turning rotors, only replacing them. As always, refer to the service information for the vehicle you are working on. After servicing the rotor, install the pads in the caliper bracket. Then install the caliper assembly on the vehicle. Be sure to lubricate the caliper slides with high temperature silicone grease and tighten all of the fasteners to the proper torque specification. Before test driving the vehicle, pump the brake pedal several times, and check and add new brake fluid as necessary. During the test drive, be sure to follow the manufacturer's recommendations for breaking in the pads. Proper break-in will help ensure optimal brake system performance.
View transcript