2008 Polaris Sportsman 700/800/700 X2 EFI Service Manual, Page 283Get this manual
BRAKES This system also incorporates diaphragm (E) as part of the cover gasket; and vent port (F) located between the gasket and the coverThe combination diaphragm and vent allow for the air above the fluid to equalize pressure as the fluid expands or contractsMake sure the vent is open and allowed to functionIf the reservoir is over filled or the diaphragm vent is plugged the expanding fluid may build pressure in the brake system leading to brake fail When servicing Polaris ATV brake systems, use only Polaris DOT-approved brake fluid
BRAKE NOISE TROUBLESHOOTING
POSSIBLE CAUSE Operator error (riding the brakepark brake applied) Loose wheel hub or bearings Brake disc warped or excessively worn Brake disc misaligned or loose Noise is from other source (chain, axle, hub, disc or wheel) Wrong pad for conditions REMEDY Educate operator Tighten wheel, hub nuts or replace bearings if worn Replace disc Inspect and repair as necessary If noise does not change when brake is applied check other sourcesInspect and repair as necessary Change to softer or harder pad (if available)