1985-1986 Honda ATC250R Shop Manual, Page 215Get this manual
HYDRAULIC DISC BRAKES BOOT
DISASSEMBLY
Remove the following: rubber bootsnap ring and push rodmaster piston, primary cup and springClean the master piston and inside of the master cylinder with clean brake fluid
SNAP RING PLIERS
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INSPECTION
Check the primary and secondary cups for wear, deterioration or damageCheck the master cylinder and master piston for scratches, scoring or damageMeasure the master cylinder inside diameter and master piston outside diameterSERVICE LIMITS: MASTER CYLINDER 1.0 14.055 mm (0.5533 in) MASTER PISTON 0.0 13.945 mm (0.5490 in) NOTE [-The replaced as set-