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 DiscIntake Air Pressure Sensor #1 Input Voltage Inspection
NOTE
Be sure the battery is fully charged.
Turn the ignition switch to OFF.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the intake air pressure sensor #1 connector
and connect the measuring adapter [A] between these
con ...
KIBS Hydraulic Unit Removal
NOTICE
The KIBS hydraulic unit [A] has been adjusted
and set with precision at the factory. Therefore, it
should be handled carefully, never struck sharply,
as with a hammer, or allowed to fall on a hard
surface.
Be careful not to get water or mud on the KIBS hydraulic
unit.
Drain the b ...
Storage of Removed Parts
After all the parts including subassembly parts have been
cleaned, store the parts in a clean area. Put a clean cloth
or plastic sheet over the parts to protect from any foreign
materials that may collect before re-assembly.
Inspection
Reuse of worn or damaged parts may lead to serious acci ...