1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 193Get this manual
HYDRAULIC DISC BRAKES OISASSEMBLY
Removethe piston bootandthesnap ringfromthe mastercylinderTOOL: Snap ring pliers
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Remove the master piston and spring from the master cylinderClean the master cylinder and master piston in clean brake fluid
(1) SNAP RING PLIERS
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 1.014.055 mm 10.5533 in) MASTER WSTON 0.0 13.945 mm 10.5490 in) NOTE The piston, piston cup and spring must be replaced as set