1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 117Get this manual
BRAKE SERVICE Type Hydraulic Caliper Service (Continued) Cleaning And Inspecting
Check all parts for wear or damage and replace any found defective123Clean all parts, except brake pads, with denatured alcohol and wipe dry with clean, lint-free clothUsing an air hose, blowout the drilled passages and boresInspect casting cylinder bore for scoring, pitting, or corrosionA corroded or deeply scored casting should be replaced; light scores and stains may be removedPolish any discolored or stained areas with crocus cloth onlyUse finger pressure and rotate the crocus cloth in the cylinder boreDo not slide the cloth in and out of the bore under pressureDo not use any other kind of abrasive or abrasive clothCheck piston to see if it is pitted, scored, or wornIf so, discard and replace the pistonDo not attempt to polish or sand pistonClean piston with denatured alcohol and wipe dry with clean, lint-free clothUsing an air hose, blow dryCheck inlet and bleeder hole threads for damage