2003 Polaris ATV Trail Boss 330 Factory Service Manual, Page 182Get this manual
TROUBLESHOOTING
Brakes Squeal Dirtycontaminated friction pads Improper alignment Worn disc Worn disc splines Poor Brake Performance Air in system Water in system (brake fluid contaminated) Caliperdisc misaligned Caliper dirty or damaged Brake line damaged or lining ruptured Worn disc andor friction pads Incorrectly adjusted lever Incorrectly adjusted stationary pad Worn or damaged master cylinder or components Improper clearance between lever and switch