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 DiscIdle Speed Control Valve Actuator Resistance Inspection
Turn the ignition switch to OFF.
Remove the air cleaner housing (see Air Cleaner Housing
Removal in the Fuel System (DFI) chapter).
Disconnect the idle speed control valve actuator connector
[A].
Connect a digital meter to the idle speed control valve
actuator connector [A]
...
Fuel Tank Cap
To open the fuel tank cap, pull up the
key hole cover. Insert the ignition key
into the fuel tank cap and turn the key
to the right.
To close the cap, push it down into
place with the key inserted. The key
can be removed by turning it to the left
to the original position. Close the key
hol ...
Check 3-4: Turn Signal Indicator Light (LED) Inspection
Connect the leads in the same circuit as Check 3-2.
Connect the terminal [5] to the battery (+) terminal.
Connect the terminal [6] to the battery (+) terminal.
Check that the turn signal indicator light (LED) [A] goes
on.
If the indicator light does not go on, replace the meter ...