Snowmobile Polaris 800 RMK / 800 Pro-RMK / 800 RMK (2010 year). Manual - part 21

85

MAINTENANCE

Drive Chain Tension

Check drive chain tension weekly and before each long trip. 

1. Remove the side panels.

2. Rotate the driven clutch 

counter-clockwise to move all 
chain slack to the tensioner 
side. Lock the brake lever 
lock, or have an assistant hold 
the brake lever firmly.

3. Loosen the adjuster bolt jam 

nut.

4. Finger tighten the adjuster bolt 

until it can no longer be 
adjusted by hand, then back 
off 1/4 turn.

5. Tighten the jam nut while 

holding the adjuster bolt. 
Torque to 21 ft. lbs. (28 Nm).

6. Reinstall the side panels.

7. Release the brake lever lock.

Jam 

Nut

Adjuster 

Bolt

86

MAINTENANCE

Brakes

Hydraulic Brake Inspection

Inspect the brake lever reserve before each use of the snowmobile. See 
page 51.

Brake pads must be replaced when the brake pad material becomes thin-
ner than the backing plate (approximately 1/16I). A kit is available for 
replacing brake pads. See your dealer.

WARNING! Brake failure during operation can result in serious injury or death. 
Properly functioning brakes are vital to your safety. Be sure the brake pads do 
not drag on the disc and that brake lever travel is not excessive. Always replace 
brake pads when the brake pad material becomes thinner than the backing plate 
(approximately 1/16

I

).

Brake Components

1. Brake Caliper

2. Brake Disc

3. Brake Pad Material (Replace 

when thickness is less than 1/
16I/1.5 mm).

4. Anti-rattle springs (come 

with brake pad kit)

Excessive Lever Travel

Hydraulic brakes are self-adjust-
ing, but if excessive brake pad 
clearance develops, bring the 
snowmobile to an authorized 
POLARIS dealer for inspection 
and adjustment.

2

1

3

4

87

MAINTENANCE

Brakes

Brake Fluid

The brake fluid level can be seen through a plastic sight glass in the 
brake reservoir. If the fluid is sufficient, the sight glass will be black. If 
the sight glass is any color other than black, add brake fluid.

Replace brake fluid at least every two years with POLARIS DOT 4 high 
temperature brake fluid. See page 104 for the part numbers of POLARIS 
products.

WARNING! After opening a bottle of brake fluid, always discard any unused 
portion. Never store or use a partial bottle. Brake fluid is hygroscopic, meaning it 
rapidly absorbs moisture from the air. The moisture causes the boiling 
temperature of the brake fluid to drop, which can lead to early brake fade and 
the possibility of accident or serious injury.

WARNING! Keep the master cylinder cover free of dirt and debris. The vent slits 
allow for diaphragm movement, and if they become plugged, movement of 
brake fluid below the diaphragm may be restricted, altering brake function.

NOTICE: Brake fluid will damage labels, paint and some plastics. Always wipe 

up spills immediately.

88

MAINTENANCE

Brakes

Bleeding the Hydraulic Brake System

Air in the hydraulic brake system will cause spongy brake lever action. 
Bleed the system before operating the snowmobile.

WARNING! Operating the vehicle with a spongy brake lever can result in loss of 
brakes, which could cause an accident and lead to serious injury or death. 
Never operate the vehicle with a spongy-feeling brake lever.

During the bleeding procedure, keep the brake handle as level as possi-
ble. The reservoir must be in this position to minimize the possibility of 
air entering the system through the reservoir vent.

1. Remove the brake master cylinder reservoir cover and gasket.

2. Fill the master cylinder reservoir to between the MIN and MAX 

marks or 1/4-5/16I (.6-.8 cm) below the lip of the reservoir opening. 
Reinstall the gasket and cover.

3. Slip a rubber tube over the ball of the bleeder valve and direct the 

flow of fluid into an approved container.

4. Squeeze the brake lever a full stroke. Then unscrew the bleeder 

valve 3/4 of a turn to release air.

5. Close the bleeder valve and release the brake lever.

6. Repeat steps 4 and 5 until fluid flows from the bleeder valve in a 

solid stream free of air bubbles.

WARNING! Overfilling the master cylinder leaves no room for fluid expansion 
and may cause the brakes to lock, resulting in serious injury or death. Always 
add brake fluid to the fill line as recommended.

7. After bleeding is complete, refill the reservoir to the proper level. 

See page 87. 

8. Reinstall the gasket and cover.