2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 311Get this manual
FRONT AND REAR BRAKES CHAS
CHECKING THE MASTER CYLINDER 1.Check: Brake master cylinder Wearscratches Replace the brake master cylinder assemblyBrake master cylinder body Cracksdamage ReplaceBrake fluid delivery passage (brake master cylinder body) Blockage Blow out with compressed air Front Rear