The brake calipers on your car or truck are essential components of its safety and performance aspects. Calipers are responsible for clamping the brake rotor when the brakes are applied, which in turn slows the wheels and the car. Inside the caliper are round seals that prevent the brake fluid from leaking out and ensure that the calipers deliver the proper pressure needed to slow the car. Calipers can be rebuilt with the proper rebuild kits.
Loosen the lug nuts for the vehicle's road wheels. Using a floor jack, raise the vehicle with the proper jacking points and lower it safely onto jack stands. Remove the wheels and place them out of the way.
Clean the caliper and nearby parts (rotors, brake line, hub, etc.) with brake cleaner. Wipe everything down with a clean rag. Remove the caliper bolts with a socket. The caliper bolts are located behind the caliper on the top and bottom. Remove the brake line that is attached to the caliper.
Clean the entire brake caliper on the work bench with brake cleaner. The pistons are held firmly in the caliper because of the rubber seals. There is a rubber O-ring seal in the caliper that ensures that brake fluid does not leak out. There is also a dust seal on the outer part of the piston where it makes contact with the brake pad.
Remove the dust seals over the pistons and then withdraw the pistons from the caliper. You may need to blow some compressed air into the hole for the brake line to get the piston to come out. Place a block of wood between the pistons to prevent the calipers from flying out suddenly from the air. Use an air compressor or a bicycle pump to pump air into the caliper.
Remove the old O-ring seals inside the caliper. Clean the insides of the caliper with brake cleaner and a clean, dry rag until they are completely clean.
Lubricate the new rubber seal and the caliper pistons with clean brake fluid to ease installation of the pistons. Insert the new seal into the groove in the caliper. Slide the pistons back into the caliper. Install the dust seals on the pistons once they are slid far enough into the caliper to allow the dust seals to be installed. The seals are usually installed by pulling them over the lip of the piston and then installing a round metal ring that clamps the rubber seal to the piston.
Slide the caliper back over the rotor. You may need to compress the caliper pistons into the caliper to allow enough clearance to fit over the rotor. Tighten the caliper bolts with a socket. Install the brake line. Bleed the brakes according to the manufacturer's procedure.
Replace the road wheels. Lower the vehicle to the ground and tighten the lug nuts. Carefully test drive the vehicle to make sure the brakes are working properly.