How to Replace Brake Disks

Disk brakes are the dominant automotive braking technology in use today. The working principle is simple. A stationary caliper uses specially designed pads to "grab" a disk that is fixed to the rotating wheel, and the resulting friction slows the vehicle. The pads and the disk are subjected to tremendous forces and heat during this process, and both are exposed to the harsh environment created beneath the vehicle as it is moving. As a result of wear or damage, it often becomes necessary to replace the brake disks, and vehicle owners can save themselves money if they are willing to spend a couple of hours doing this relatively easy task themselves.

Instructions

1

Park the vehicle on a firm and level surface. Put automatic transmissions in park and put manual transmissions in first or reverse gear. If working on a front brake, set the parking brake and block both rear wheels. If working on a rear brake, do not set the parking brake and block both front wheels. Partly loosen the lug nuts on the wheel to be serviced, jack up the vehicle and support the vehicle on a safety stand. Completely remove the lug nuts and pull the wheel off.

2

Remove any protective caps that might cover the heads of the two caliper guide bolts, and then remove the caliper guide bolts. Grip the caliper assembly and roll it back and forth a few times to spread the brake pads, and then lift the caliper assembly up and off the disk. Do not damage the rubber brake hose. Hang the caliper assembly out of the way on the vehicle suspension using a bungee cord or similar.

3

Remove the old disk by removing any retaining bolts or screws and pulling the disk off the hub. If the disk is seized, tap the center part of the disk firmly with a rubber or plastic mallet to loosen. Some disks have one or more threaded holes in the center part of the disk. Bolts can be threaded into these holes and simultaneously tightened to jack the disk off the hub.

4

Clean the hub thoroughly with brake cleaning fluid. Be sure to catch all used fluid in a catch pan and dispose of the used fluid in accordance with local regulations. Work in a well-ventillated area and take care not to breathe brake cleaning fluid vapors. Use a wire brush to remove stubborn dirt and deposits. Wipe the hub down with rags. Check the surface of the new disk that will contact the hub and be sure it is free from dirt. Clean with brake cleaning fluid if necessary.

5

Place the new disk on the hub and secure it with retaining bolts or screws if applicable.

6

Pry the caliper assembly brake pads apart using a thin piece of wood or similar soft object. Replace the caliper assembly over the disk. Lubricate the caliper guide bolts with brake grease and reinstall to secure the caliper. Reinstall the wheel and lower the vehicle. Test the brake operation before driving the vehicle normally.