Overhaul

Front Disc Brake Caliper

Disassembly

• Before disassembling the brake caliper, remove it from the vehicle. Refer to => [ Front Disc Brake Caliper ] Front Disc Brake Caliper.

• Before disassembling the brake caliper, clean and inspect it. Refer to => [ Disc Brake Caliper Cleaning ] Disc Brake Caliper Cleaning and to => [ Disc Brake Caliper Inspection ] Disc Brake Caliper Inspection.


Under no condition should high pressure air ever be used to remove a piston from a caliper bore. Personal injury could result.


Do not use excessive force when clamping caliper in vise. Excessive vise pressure will cause bore distortion.

- Mount the caliper in a vise equipped with protective jaws.






• 1 - Wood block.


Do not place face or hands near caliper and piston if using compressed air pressure to remove piston. Do not use high pressure.

- Place a wooden block (1) in the caliper as shown.

- If necessary, apply low pressure compressed air to the caliper fluid inlet in short spurts to force the piston out.

- Remove the piston from the caliper.

- Remove the dust boot from the piston and discard it.






• 1 - Trim stick.

• 2 - Seal.


Do not use a screw driver or other metal tool for seal removal. Using such tools can scratch the bore or leave burrs on the seal groove edges.

- Using a soft tool such as a plastic trim stick (1), work the piston seal (2) out of its groove in caliper piston bore. Discard the used seal.

- Clean the piston bore and drilled passage ways with alcohol or a suitable solvent. Wipe it dry using only a lint-free cloth.

- Inspect both the piston and bore for scoring or pitting. Bores that show light scratches or corrosion can usually be cleared of the light scratches or corrosion using crocus cloth.

Assembly

• Always have clean hands when assembling a brake caliper.

• Always use fresh, clean brake fluid when assembling a brake caliper.






• 1 - Seal.

• 2 - Groove.

• Never use an old piston seal.

- Dip the new piston seal in clean brake fluid and install it in the groove (2) of the caliper bore. The seal (1) should be started at one area of the groove and gently worked around into the groove using only clean fingers to seat it.






- Coat the new piston with clean brake fluid.

- Coat the new piston boot with clean brake fluid leaving a generous amount inside the boot.

- Position the dust boot over the lower section of the piston.

- Extend the dust boot below the bottom of the piston and guide the lip seal into the groove in the caliper piston bore.






• 1 - Piston groove.


Force applied to the piston to seat it in the bore must be applied uniformly to avoid cocking and binding of the piston.

- Install the piston (1) into the bore, carefully pushing it past the piston seal using hand pressure. Push the piston in until it bottoms in the caliper bore and the dust boot lip seal falls into the groove near the top of the piston.

- Install the caliper on the vehicle and bleed the brakes as necessary. Refer to => [ Front Disc Brake Caliper ] Front Disc Brake Caliper.