Replacing Rear Disc Brakes

Replacing rear disk brakes will not be required as often as front disk brakes, since front disk brakes provide as much as 80% of the required braking power. Rear disc brakes are important however, as they are often responsible for the emergency brake system.

Disc brakes work like the brakes on a bicycle, except that disc brakes use a metallic composite pad instead of rubber. The rotor is a metal disc that serves the same purpose as the rim of a bike tire and the caliper is the device that holds the brake pads in place.

How To Replace Rear Disc Brakes

• Going up. Chock the tires so the car won't slip off the jack. Loosen the lug nuts on the rear wheels. Jack the rear of the car up and remove the wheels. Lower the car onto a jack stand.
• Remove the calipers. The rear brake calipers are mounted so that they sit over a portion of the rotor. On smaller cars, the calipers may be spring mounted, but on most cars, the calipers are bolted to a supporting bracket. Remove the calipers, leaving the brake line hoses attached. Find a stable location to place the calipers so that the brake hoses do not stretch or come loose.
• Remove the brake pads. Depending on the design, the brake pads will remain in the caliper or on the rotor. In either case, remove the brake pads and their hardware.
• Inspect the rotors. The rotors sit over the wheel hubs and have a flat metal surface. If the surface is grooved or glazed (has a shiny surface) the rotors will have resurfaced at a machine shop or auto store. The rotors of some rear disc brakes slide off over the wheel hub, but many are held in place using a setscrew.
• Reset the caliper. The rear disc brake calipers have a piston that applies pressure to the brake pads. Before new brake pads can be installed, the caliper pistons must be reset. Piston compression methods vary: some calipers require that the piston be screwed into position using a special tool, while others can be compressed using a c-clamp or an inexpensive spreader tool. Use extra care with this step-damaging the piston will mean replacing the caliper.
• Reinstall the brake pads. Either reinstall the brake pads or install new ones as required.
• Reinstall the calipers. Return the calipers to their proper positions and mount appropriately with springs or bolts.
• Bleed the brake lines. You'll need to bleed your brakes to remove any air that has gotten into the brake lines.
• Replace the wheels. When you're finished, replace the wheels securely and lower the car. Before driving the car, press the brake pedal down completely and then slowly release it. Test the brakes thoroughly before driving the car at normal driving speeds.