If a master cylinder or piston shows any damage, replace them.

If a cup is worn, damaged softened (rotted), or swollen, the piston assembly should be replaced to renew the cups.
If fluid leakage is noted at the brake lever, the piston assembly should be replaced to renew the cups.
If they are damaged, replace them.
If the springs are damaged, replace them.
If the relief port becomes plugged, the brake pads will drag on the disc. Blow the ports clean with compressed air.
Front Master Cylinder [I] Rear Master Cylinder [J]

Rear Master Cylinder Installation
Brake DiscExhaust Butterfly Valve Actuator Installation
Install the pulley [A] on the actuator so that the hole side
[B] align with the groove [C] on the shaft.
Make sure that the groove on the shaft is pointing toward
the center of the screw [D].
If the shaft position is incorrect, refer to the following
NOTE and procedures to electrically ad ...
Front Brake Pad Installation
Check that the pad spring [A] is in place on the caliper.
Push the caliper pistons in by hand as far as they will go.
Install the brake pads [A] on the pad spring correctly.
Fit the pad into the groove of the caliper as shown in the
figure.
Install the pad pins while pushing t ...
Stator Coil Installation
Apply a non-permanent locking agent to the threads of
the stator coil bolts and tighten them.
Torque - Stator Coil Bolts: 12 N·m (1.2 kgf·m, 106 in·lb)
Using a high flash-point solvent, clean off any oil or dirt
that may be on the silicone sealant coating area. Dry
them with a clea ...