14. REAR WHEEL/SWING ARM/ HYDRAULIC BRAKE ATV 50 Disassembly Remove the piston rubber cover and snap ring from the brake master cylinder. Snap Ring Pliers Master Cylinder Remove the washer, main piston and spring from the brake master cylinder. Clean the inside of the master cylinder and brake reservoir with brake fluid. Spring Main Piston Snap Ring Inspection Measure the brake master cylinder I.D. Inspect the master cylinder for scratches or cracks. Service Limit: 12.75 mm (0.51 in) replace if over Measure the brake master cylinder piston O.D. Service Limit: 12.64 mm (0.5056 in)replace if below 14-21