2005 Polaris Sportsman 700/800 EFI Service Manual, Page 239Get this manual
BRAKES when the lever is released and the master cylinder piston is outwardAs the temperature within the hydraulic system changes, this port compensates for fluid expansion (heated fluid) or contraction (cooled fluid)During system service, be sure this port is openDue to the high temperatures created within the system during heavy braking, it is very important that the master cylinder reservoir have adequate space to allow for fluid expansionNever overfill the reservoir! Fill to 14516 (.64.80 cm) from top of the cylinderThis 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 failureWhen servicing Polaris ATV brake systems, use only Polaris DOT Brake Fluid (PN 2870990)WARNING: Once bottle is opened, use what is necessary and discard the rest in accordance with local lawsDo not store or use partial bottle of brake fluidBrake fluid is hygroscopic, meaning it rapidly absorbs moistureThis causes the boiling temperature of the brake fluid to drop, which can lead to brake fade and the possible loss of controlNOTE: Uppermost (inner) bleed screw and brake line (A) is for hand brake systemLower (outer) bleed screw and brake line (B) is for auxiliary (foot) brake system