RearCaliper Piston and Seal

CALIPER PISTON AND SEAL

NOTE: Before disassembling brake caliper, clean and inspect it. Disc Brake Caliper - Inspection

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

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

1. Mount caliper in a vise equipped with protective jaws.




2. Place a wooden block (1) in caliper as shown. Block should be sized to allow piston to push out of bore far enough to be removed by hand after being loosened by air pressure, yet large enough keep piston from coming completely out utilizing air pressure.

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

3. Apply low pressure compressed air to caliper fluid inlet in short spurts to ease piston out of bore.
4. Remove piston from caliper.




5. Remove dust boot (3) and discard it.




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

6. Using a soft tool such as a plastic trim stick (1), work piston seal (2) out of its groove in caliper piston bore. Discard old seal.
7. Remove caliper bleeder screw.
8. Clean piston bore and drilled passage ways with alcohol or a suitable solvent. Wipe it dry using only a lint-free cloth.
9. Inspect both piston and bore for scoring or pitting. Bores that show light scratches or corrosion can usually be cleared of light scratches or corrosion using crocus cloth.