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 DiscRear Frame Front Removal
Remove:
Rear Frame Rear (see Rear Frame Rear Removal)
Rear Fender Front (see Rear Fender Front Removal)
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracket [B]
Rear Frame Front Bolts [C]
Left Rear Frame Front [D]
Remove:
Rear Footpeg Bracket Bolts [A]
Rear Footpeg Bracke ...
Seat Cover Removal
Remove:
Rear Seat (see Rear Seat Removal)
Remove the bolts [A].
Remove the upper seat cover backward [B] to clear the
hook portions.
Remove:
Front Seat (see Front Seat Removal)
Quick Rivets [A]
Bolts [B]
Seat Covers [C]
...
Specifications
Whenever you see the symbols
shown below, heed their instructions!
Always follow safe operating and maintenance
practices.
DANGER
DANGER indicates a hazardous
situation which, if not avoided,
will result in death or serious injury.
WARNINGWARNING indicates a hazardous
situation whi ...