Brake System Service Notes; Brake System Operation - Polaris Sportsman XP 1000 S 2020 Service Manual

BRAKE SYSTEM

BRAKE SYSTEM SERVICE NOTES

Disc brake systems are light weight, low maintenance,
and perform well in the conditions this vehicle will
routinely encounter. There are a few things to remember
when replacing disc brake pads or performing brake
system service to ensure proper system function and
maximum pad service life.
• DO NOT over-fill the master cylinder fluid reservoir(s).
• Make sure the brake lever / pedal returns freely and
completely.
• Adjust stop pin on calipers after pad service.
• Check and adjust master cylinder reservoir fluid level
after pad service.
• Make sure atmospheric vent on reservoir is
unobstructed.
• Test for brake drag after any brake system service and
investigate cause if brake drag is evident.
• Make sure caliper moves freely on guide pins (where
applicable).
• Inspect caliper piston seals for foreign material that
could prevent caliper pistons from returning freely.
• Perform a brake burnishing procedure after installing
new pads to maximize service life. See Brake
Burnishing Procedure page 10.33.
• DO NOT lubricate or clean the brake components with
aerosol or petroleum products. Use only approved
brake cleaning products.
• DO NOT allow brake cleaning products to contact
painted surfaces. Paint damage will occur as a result.

BRAKE SYSTEM OPERATION

The brake system consists of the following components
or assemblies, which are secured to the drive line.
• Front brake master cylinder with brake lever
• Rear brake master cylinder with brake pedal
• Brake fluid reservoirs
• Brake lines
• Brake calipers
• Brake pads
• Brake discs
• Distribution block reducing valve (International Models
only)
• Reducing valve (International Models only)
10.4
When the brake lever or pedal is applied, it moves the
hydraulic piston within the master cylinder. As the piston
moves inward it closes a small opening (compensating
port) within the cylinder and starts to build pressure
within the brake system. As the pressure within the
system is increased, the pistons located in the brake
calipers move outward and apply pressure to the
moveable brake pads. These pads contact the brake
discs and move the calipers in their floating bracket,
pulling the stationary side pads into the brake discs. The
resulting friction reduces brake disc and vehicle speed.
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 which is opened and closed by the master cylinder
piston assembly. As the temperature within the hydraulic
system changes, this port compensates for fluid
expansion or contraction. 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.
IMPORTANT
Do NOT fill the reservoir beyond the MAX LEVEL line.
When servicing Polaris brake systems, only use Polaris
DOT 4 Brake Fluid.
Once a bottle is opened, use what is necessary and
discard the rest in accordance with local laws. Do not
store or use a partial bottle of brake fluid. Brake fluid is
hygroscopic, meaning it rapidly absorbs moisture. This
causes the boiling temperature of the brake fluid to
drop, which can lead to early brake fade and the
possibility of serious injury.
9931493 R03 - 2020-2021 Sportsman XP 1000 S Service Manual
WARNING
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