Operation Overview - Polaris Hawkeye Repair Manual

BODY AND STEERING

Operation Overview

Must be clear to
allow proper
diaphragm
movement
F
A B
Move Brake Pad
The Polaris disc brake system consists of the following
components or assemblies: hand brake lever; foot brake lever,
hand and foot brake master cylinders; hydraulic hoses; brake
calipers (slave cylinders); brake pads; and brake discs, which
are secured to the drivetrain.
When the hand activated brake lever (A) is applied it contacts
piston (B) within the master cylinder. As the master cylinder
piston moves inward it closes a small opening (compensating
port C) within the cylinder and starts to build pressure within
the brake system. As the pressure within the system is
increased, the piston (D) located in the brake caliper moves
outward and applies pressure to the brake pad. This pad
contacts the brake disc and moves the caliper in its floating
bracket, pulling the stationary side pad into the brake disc.
The resulting friction reduces brake disc and vehicle speed.
As the lever pressure is increased, the braking affect is also
increased.
6.6
- www.instant-manuals.com -
Compensating port
E
compensates for
temperature changes by
allowing fluid back to
master cylinder
C
D
The friction applied to the brake pads will cause the pads to
wear. As these pads wear, the piston within the caliper moves
further outward and becomes self adjusting. Fluid from the
reservoir fills the additional area created when the caliper
piston moves outward.
Brake fluid level is critical to proper system operation. Too
little fluid will allow air to enter the system and cause the
brakes to feel spongy. Too much fluid could cause brakes to
drag due to fluid expansion.
Located within the master cylinder is the compensating port
(C) which is opened and closed by the master cylinder piston
assembly. The port is open when the lever is released and the
master cylinder piston is outward. As 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 open. Due 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 expansion. Never overfill
the reservoir! Fill to 1/4, - 5/16, (.64 - .80 cm) from top of
the cylinder.
This system also incorporates a diaphragm (E) as part of the
cover gasket; and a vent port (F) located between the gasket
and the cover. The combination diaphragm and vent allow for
the air above the fluid to equalize pressure as the fluid
expands or contracts. Make sure the vent is open and allowed
to function. If 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 DOT 3
or DOT 4 Brake Fluid.
WARNING
Once a bottle is opened, use what is necessary and dis-
card the rest in accordance with local laws. Do not store
or use a partial bottle of brake fluid. Brake fluid is hy-
groscopic, meaning it rapidly absorbs moisture. This
causes the boiling temperature of the brake fluid to drop,
which can lead to brake fade and the possible loss of con-
trol.