Checking the caliper piston and replacing the piston protection ring

If the protective ring is damaged or carelessly installed, dirt and moisture penetrate the caliper cylinder. In this case, it is necessary to replace the ring as soon as possible, otherwise the piston may seize due to dirt and corrosion, which will lead to increased wear of the brake pads and disc and uneven braking.



SEQUENCE OF WORK

1. Remove the brake pads as described above.

2. Check if the brake pads move easily in their guides. Otherwise, grind the guides to a shine, being careful not to damage or move the piston protection ring from its place. Apply some grease to the mating surfaces before installing the brake pads (copper paste).

3. Check up smoothness of movement of brake supports and if necessary grease them with copper paste.

Caliper Piston Check

1. To check if the piston moves easily, place a clamp with a block of wood inserted as brake pads for the piston to prevent the piston from extending too far. Naturally, the caliper on the second wheel must be in its normal working position.

2. Have an assistant gently depress the brake pedal. Check if the piston moves easily. If the piston does not extend, depress the brake pedal until the piston begins to move. Press the piston into the caliper cylinder with a clamp. Repeat this operation until the piston moves easily. Lubricate the sides of the piston with brake fluid.


WARNING

If you are unable to restore the mobility of the piston, stop work and return the caliper for repair.

Replacing the piston protection ring

1. Using a bent wire or small bent screwdriver, remove the protective ring from the brake caliper and sliding piston. At the same time, try not to scratch the working surfaces of the sliding piston and cylinder. At the same time, check to see if brake fluid is leaking from the cylinder. Just in case, it is better to take the brake caliper to a car repair shop.

2. Clean sealing surfaces with alcohol or clean brake fluid. Before you install a new protective ring, lubricate the cleaned surfaces with a preservative.

3. Carefully place a new protective ring on the sealing surfaces. Make sure that the protective ring sits tightly in its place.

4. Press the piston back into the cylinder until it stops.

5. Install the brake pads.

6. After finishing work, check the level of the brake fluid and the tightness of the hydraulic drive of the brake system.