Content Source: 2019 850 PRO-RMK / SKS 155 Owner’s Manual (9928946 R01) > Maintenance Chapter

IMPORTANT

The Owner's Manual for this vehicle contains warnings, instructions and other information you must read and fully understand before safely riding or performing maintenance on this vehicle.Always follow the warnings and instructions in Owner's Manual.

Click the CONTENTS link above for the Table Of Contents, or download a full PDF of the Owner Manual in the Owner Support area of Polaris.com

Brakes

Hydraulic Brake Inspection

Inspect the brake lever reserve before each use of the snowmobile. See Brake Lever Travel.
Brake pads must be replaced when the brake pad material becomes thinner than 1/16 inch (1.5 mm). A kit is available for replacing brake pads. Your POLARIS dealer can assist.
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 1/16 inch (1.5 mm).

Brake Components

  • Brake Caliper
  • Brake Disc
  • Brake Pad Material - Replace when thickness is less than 1/16 inch (1.5 mm).

Image

Excessive Lever Travel

Hydraulic brakes are self-adjusting, but if excessive brake pad clearance develops, bring the snowmobile to an authorized POLARIS dealer for inspection and adjustment.
TIP
The lightweight brake discs have vent holes that may cause a high-pitched sound during operation.

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, or an equivalent product.
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.

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 possible. 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 1/4-5/16 inch (.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 4–5 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 Brake Fluid.
  8. Reinstall the gasket and cover.
NOTE
6–8 in lbs (0.7–0.9 Nm)

© Copyright Polaris Industries Inc. All rights reserved.