Snowmobile Polaris IQ (2007-2008 year). Manual - part 45

6.10

Final Drive and Brakes

BRAKE SYSTEM

Overview

The Polaris snowmobile hydraulic brake system consists of the
following components or assemblies: brake lever, master
cylinder, hydraulic hose, brake caliper (slave cylinder), brake
pads, and a brake disc which is secured to the drive line.

When the hand activated brake lever (A) is applied, it contacts
a piston (B) within the master cylinder. As the master cylinder
piston moves inward it closes a small opening called a
compensating port (C) within the cylinder and starts to build
pressure within the brake system. As the pressure within the
system is increased, the pistons (D) located in the brake caliper
move toward the disc and applies pressure to the moveable
brake pads. As the lever pressure is increased, the braking effect
is increased.

The friction applied to the brake pads will cause the pads to
wear. As the pads wear, the piston within the caliper self-adjusts
and moves further outward.

Brake fluid level is critical to proper system operation. A low
fluid level allows air to enter the system causing the brakes to
feel spongy.

Compensating Port

Located within the master cylinder is a small compensating port
(C) which is opened and closed by the master cylinder piston
assembly. The port is open when the brake lever is released and
the piston is outward. As the temperature within the hydraulic
system changes, this port compensates for fluid expansion
caused by heat, or contraction caused by cooling. 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 the brake fluid to expand. Master cylinder reservoirs
should be filled to the top of the fluid level mark on the inside
of the reservoir, 1/4" - 5/16" (.6 -.8 cm) below lip of reservoir
opening.

This system also incorporates a diaphragm (E) as part of the
cover gasket and a vent port (on cover) 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. Be sure the vent is open and allowed to
function. If the reservoir is overfilled or the diaphragm vent is
plugged, the expanding fluid may build pressure in the brake
system and lead to brake failure.

A

B

E

C

D

6.11

Final Drive and Brakes

6

General Guidelines

Keep these points in mind when bleeding hydraulic brakes:

• The master cylinder reservoirs have limited capacities. 

It is easy to empty them during the bleeding procedure. 
This introduces air into the system which you are trying 
to purge. Watch the reservoir closely and add fluid 
when necessary to prevent air from entering the system.

• Apply only light to moderate pressure to the lever or 

pedal when bleeding the brake system. Extreme 

pressure will cause a surge of fluid through the small 
orifices of the brake system when the bleeder screw is 
opened and introduce air into the system by means of 
cavitation.

• Small amounts of air can become trapped in the banjo 

bolt fittings at the master cylinder(s) and junction points 
of brake lines. These fittings can be purged of air by 
following a standard bleeding procedure at these 
fittings (instead of the bleed screw on caliper) if 
necessary to speed the bleeding process. This is usually 
only needed if system was completely drained of fluid. 
Bleed each line connection, starting with the fitting 
closest to the master cylinder, working toward the 
caliper, and ending with the bleed screw. 

• Always torque banjo bolts and other brake system 

fittings to specified torque.

• Change fluid every 2 years, or when fluid is dark or 

contamination is suspected.

Brake Fluid Replacement & Bleeding

This procedure should be used to change fluid or bleed brakes
during regular maintenance, or after complete brake service.
Brake fluid may damage painted or plastic surfaces. Take care
not to spill, and wipe up any spills immediately. Cover parts to
avoid damage.

1.

Clean the reservoir cover.

2.

Remove the two T-15 Torx™ screws from the cover.

3.

Carefully remove the cover and diaphragm assembly from
the reservoir.

4.

Under the cover, inspect the vent slots under the bellows
and remove any debris or blockage.

5.

Bleed or replace the fluid by attaching a clear hose from the
caliper bleeder fitting to a clean container. Be sure the hose
fits tightly on the bleeder fitting.

6.

Pump the brake lever a few times and hold.

7.

Slowly open the bleeder fitting and let the old fluid or air

WARNING

An unsafe condition exists when air is trapped in the 

hydraulic brake system. Air in the brake hydraulic 

system acts like a soft spring and absorbs a large 

percentage of the pressure developed by the master 

cylinder. Without this pressure, the braking system 

cannot develop full braking force to allow for safe, 

controlled stops. It is extremely important to bleed the 

brakes properly after any brake system work has been 

performed or when inspection reveals spongy brakes.

A soft, spongy feeling in the brake lever and/or brake 

pedal could indicate a hazardous condition in the brake 

system. Do not operate the vehicle until the failure in 

the brake system is corrected.

Keep brake fluid tightly sealed and out of reach of 

children. Brake fluid can accumulate moisture, 

reducing it's effectiveness.

Contaminated brake discs or brake pads greatly 

reduce braking performance and increase stopping 

distance. Do not attempt to clean contaminated pads. 

Replace them. Clean the brake disc with brake cleaner.

This brake system requires ethylene-glycol based fluid 
(DOT 4). Do not use or mix different types of fluid such 

as silicone-based or petroleum-based.

Do not use brake fluid taken from old, used or unsealed 

containers. Never reuse brake fluid.

CAUTION

Pressure bleeding is not recommended. When fluid 

surges through the fittings, it is possible to cavitate the 

fluid and create air in the system. In addition, the fluid 

stored in a pressure bleeder may be contaminated. Al-

ways use fresh DOT 4 brake fluid from a sealed con-

tainer.

6.12

Final Drive and Brakes

escape. You will feel the lever release as you let the fluid
or air escape.

8.

Pump the brake lever a few times and hold it again.

9.

Repeat steps 7 and 8 until you see new brake fluid coming
from the caliper bleeder fitting or if you are bleeding the
air, repeat this step until you see only fluid coming out. This
may take several intervals.

10. Torque the bleeder screw to 8-11 ft-lb (11-15 N-m).

11. When adding fluid, add DOT 4 brake fluid to 1/4-5/16" (.6-

.8 cm) from the reservoir top.

12. Install cover and diaphragm assembly.

13. Tighten the cover screws to 16-20 in-lb (1.8-2.3 N-m).

14. Field test machine before putting into service. Check for

proper braking action and lever reserve. Lever reserve is
when the lever is firmly applied, the lever reserve should
be no less than 1/2" (1.3 cm) from the handlebar. 

15. Verify that the sight glass indicates a full reservoir. 

16. Check brake system for any fluid leaks.

Master Cylinder / Lever Service

1.

To remove the brake lever, remove the E clip from the
lever pin.

2.

Extract the pin from the housing, then remove the lever.

3.

To remove the parking brake lever, the housing cover must
be removed. Once removed, carefully extract the spring
noting it its position inside the housing. Remove the
parking brake lever.

4.

To remove the cartridge, completely drain the brake fluid
from the housing. Remove the brake and parking brake
levers.

5.

Disconnect the brake hose from the cartridge. Carefully
pop the cartridge out of the housing.

6.

To install the cartridge, lubricate the entire surface with
DOT 4 brake fluid.

7.

Align the cartridge with the housing tabs, then firmly press
the cartridge back into the housing until the cartridge is
engaged with the tabs.

8.

Refill and bleed the brakes system as outlined in this
chapter. See “Brake Fluid Replacement & Bleeding” on
page 6.11.

= T 

Bleeder Screw: 8-11 ft-lb (11-15 N-m)

= T 

Cover Screws: 16-20 in-lb (1.8-2.3 N-m)

COVER SCREWS

COVER

PARKING BRAKE LEVER

CARTRIDGE

BRAKE LEVER

LEVER PIN

E CLIP

SWITCH

6.13

Final Drive and Brakes

6

Brake Line Replacement

Follow these steps if the brake line is to be replaced.

1.

If needed bleed the brake system by attaching a clear hose
to the caliper bleed fitting.

2.

Attach the other end to a Mity Vac or similar vacuum tool.

3.

Bleed the system of brake fluid.

4.

Note the orientation of the brake line. The brake line will
need to be replaced in the same orientation.

5.

Remove the brake line from the caliper. Cap or cover the
end to catch any brake fluid that may still be in the line.

6.

Loosen the brake line from the master cylinder 1/4 to 1/2
turn.

7.

Remove the 4 screws that hold the master cylinder to the
handlebar. This will separate the master cylinder from the
switch pack.

8.

Unplug the brake light switch harness from the master
cylinder.

9.

Remove the brake line from the master cylinder.

10. Install new brake line on caliper and orientate it as noted in

step 4.

11. Torque the caliper banjo bolt to 168-216 in-lb (19-24 N-m).

12. Insert the new brake line and install into the master

cylinder. Torque the brake line to 144-192 in-lb 
(16-21 N-m).

13. Tighten the brake line into the master cylinder in an

orientation so that the line does not have any sharp bends
when it is installed on the handlebar.

14. Route the brake light switch in the harness correctly.

15. Place the switch pack with the master cylinder onto the

handle bar. Two smaller screws should be placed on the top
and the longest screw is placed on the lower right.

144-192 in-lb (16-22\N-m)

brake light switch

168-216in-lb (18.9-24.4 N-m)

= T 

Caliper Banjo Bolt: 168-216 in-lb (18-24 N-m)

= T 

Brake Line: 144-192 in-lb (16-22 N-m)