Polaris ATP 330 4x4 Owner's Manual page 97

MAINTENANCE AND LUBRICATION
Adjustments
Auxiliary Brake
The auxiliary brake is a hydraulic disc brake. The rear brake system is
self-adjusting and requires no maintenance other than periodic checks
of the pads for wear.
Pads should be changed when worn to 3/64" (.1 cm), which is about
the thickness of a U.S. dime.
Inspect the brake disc spline and pad wear surface for excessive wear.
Your vehicle's auxiliary brake system is intended to be used as a
backup for the main brake system. Should the main system fail, the
rear brake can be activated by depressing the foot pedal on the inside of
the right footrest.
NOTE: Since the auxiliary brake is a rear brake only, it will not be as
effective for braking as the all-wheel single lever system.
94