Brake Piston Repair: A How to Guide

A vintage car
  • 2-8 hours
  • Intermediate
  • 30-100
What You'll Need
Piston kit
Car jack
Lug wrench or ratchet
Brake caliper piston removal tool
Air hose (optional)

Brake piston repair should be immediately taken care of, especially when you find out that the brakes of your vehicle are not functioning properly. In fact, the job can be done by anyone with basic mechanical knowledge. Before you undertake brake piston repair task, it is essential to understand the role of this component in the braking system.

When brake pedals are pressed, the force applied is transferred onto brake pistons, which press the brake liners against the wheel drum. This causes friction between brake pads and wheel drum forcing the wheel to reduce its rotational speed. Due to lot of friction and mechanical movements, brake pistons are subject to wear and tear. Thus, to keep the brake system of your vehicle in proper working condition, occasional repair or replacement of brake pistons becomes necessary.

Replacing brake pistons should be done slowly and methodically. Be sure that you have ample time and patience to undertake this do-it-yourself task.

Step-by-Step Procedure for Repairing Brake Pistons

Step 1: Park your vehicle on a leveled surface and raise it using a jack stand.

Step 2: Loosen the lug nuts using a ratchet or lug wrench. Once the loose lug nuts are removed, pull out the wheel and place it on the ground facing upwards.

Step 3: Detach the brake pads from caliper by removing the retaining clips that hold them.

Step 4: Use a large C-clamp to squeeze piston into caliper for clearance to remove caliper from rotor. This will ease pressure on calipers, thereby allowing you to easily remove them.

Step 5: The brakes pistons need to be removed now, but the one brake piston should not move while the other is being removed. A brake caliper piston removal tool comes handy in here.

Step 6: Alternatively, a pressurized air hose can also be used for blowing out the other piston while the first one is securely held in place. In this case, you have to use a C-clamp for securing the piston in place. Make sure that the caliper is wrapped in rags to prevent brake fluid from spraying while pressurized air in blown on it.

Step 7: The caliper can be cleaned now as both the pistons are out and ready to be repaired or replaced.

Step 8: The piston kit comes with piston cylinder seal, rubber dust boot, and retainer pins for pistons and brake pads. Check the condition of the brake pistons.

Step 9: If there are no apparent cracks, scratches, or fissures on the brake pistons, they just require some cleaning. Possibly, the seal or the retainer pins were damaged, which can be easily replaced.

Step 10: After everything is properly cleaned, start reassembling the entire system one by one.

Important Tips

  • Pistons must be properly oriented with the rotor.
  • Before you replace brake pads, seat the pistons in caliper using a C-clamp if necessary to gain clearance.