15. REAR BRAKE/REAR FORK/REAR WHEEL/REAR SHOCK ABSORBER GRAND DINK 250 Remove the piston from the brake caliper. If necessary, use compressed air to squeeze out the piston through the brake fluid inlet opening and place a shop towel under the caliper to avoid contamination caused by the removed piston. Check the piston cylinder for scratches or wear and replace if necessary. Compressed Air Push the piston oil seal outward to remove it. Clean the oil seal groove with brake fluid. Be careful not to damage the piston surface. Check the piston for scratches or wear. Measure the piston O.D. with a micrometer gauge. Service Limit: 30.14mm Check the caliper cylinder for scratches or wear and measure the cylinder bore. Service Limit:30.28mm 15-4