How to Bleed & Replace Brake Fluid on a 2017 Polaris Sportsman Touring 850 SP

Shop parts for a 2017 Polaris Sportsman Touring 850 SP ATV.

This MotoSport procedural guide covers a complete brake fluid service for the 2017 Polaris Sportsman Touring 850 SP – flushing old fluid, bleeding lines, and refilling the master cylinder safely. Follow these steps precisely to restore firm braking performance and protect the brake system from contamination.

What you need

  • DOT 4 brake fluid (Polaris recommends DOT 4; do not use DOT 5 silicone)
  • Clear vinyl tubing that fits bleeder nipples
  • Brake bleeder catch bottle or clear container
  • Wrenches for bleeder nipples and banjo bolts (size per bike)
  • Turkey baster or fluid transfer syringe
  • Clean rags & disposable gloves
  • Torque wrench (use factory torque specs for banjo/bolts)
  • Assistant (recommended) or a pressure/vacuum bleeder
  • Jack or lift (if needed for wheel access)

Safety & preliminary checks

  • Work on a level surface with the engine off and parking brake engaged.
  • Protect painted surfaces from brake fluid; it damages finishes. Cover surrounds with rags.
  • Confirm the system type on your MMY ATV — brake routing on the Sportsman Touring 850 SP is hydraulic discs front and rear. If your unit has electronic systems (EPS or traction systems), avoid spilling fluid on electrical components.
  • Check reservoir location — typically under the front access panel. Clean the area around the cap before opening to avoid contamination.

Step 1 – Remove old fluid from reservoir

  1. Open the master cylinder reservoir cap and remove the diaphragm cover. Use a turkey baster or syringe to remove as much old fluid as possible from the reservoir.
  2. Wipe the inside surfaces with a clean lint-free rag if contaminated. Never reuse removed fluid.
  3. Top the reservoir with a small amount of fresh DOT 4 fluid to prevent air intake while bleeding.

Step 2 – Determine bleed order

Bleed starting with the caliper farthest from the master cylinder and proceed to the nearest. A recommended sequence for the Sportsman Touring 850 SP is:

  1. Rear caliper (if single rear, do it first)
  2. Right front caliper
  3. Left front caliper

If your unit's reservoir or plumbing places the master cylinder differently, follow farthest-to-nearest relative to the reservoir. If unsure, follow the manual's sequence.

Step 3 – Bleeding technique (manual pedal/lever with assistant)

  1. Put a clear tube on the bleeder nipple and submerge the other end in a bottle partially filled with clean brake fluid to prevent air entry back into the line.
  2. Have your assistant slowly squeeze the brake lever/pedal several times and hold it on the next squeeze.
  3. Open the bleeder nipple about 1/4 turn to allow fluid and air to exit. Close the nipple before the assistant releases the lever.
  4. Repeat until clear, bubble-free fluid flows and no air is visible in the tubing.
  5. Top the master cylinder reservoir frequently to avoid running dry and introducing air into the system.
  6. Move to the next caliper in the bleed sequence and repeat.

Step 4 – Bleeding with vacuum or pressure tool (single-person option)

  1. Attach the vacuum bleeder to the bleeder nipple and pull until you see clean fluid without air. Keep reservoir topped up during the process.
  2. With a pressure bleeder on the reservoir, open each bleeder in sequence until clean fluid flows.

Step 5 – Final checks & finishing

  • When all calipers have been bled, ensure reservoir is filled to the specified level and install the diaphragm and cap tightly.
  • Pump the brake lever/pedal several times to confirm a firm feel. If the lever is spongy, repeat bleeding focusing on suspected lines.
  • Inspect banjo bolts and bleeder nipples for leaks. Tighten fasteners to factory torque specifications in the service manual.
  • Clean any spilled fluid immediately and dispose of used fluid according to local regulations.

Model-specific notes for the 2017 Polaris Sportsman Touring 850 SP

  • The Touring 850 SP may come with EPS and auxiliary electrical components near the master cylinder — keep fluid off connectors and sensors to avoid corrosion or damage.
  • Polaris uses DOT 4 on this model; mixing DOT 4 with DOT 5 (silicone) will ruin the system. If you find an unknown fluid, flush completely and use DOT 4 only.
  • If your Sportsman has a combined parking-brake or integrated park mechanism at the rear caliper, take care when loosening banjo bolts; some rear systems incorporate handbrake linkages that must be re-centered after service.
  • Use new crush washers on banjo fittings whenever you remove them to avoid leaks.
  • If you encounter persistent air that won't purge, inspect flex lines and hoses for internal collapse or the master cylinder for internal seals that may be failing. These components are wear items and should be replaced per symptoms.
  • After service, monitor brake performance closely for the next few rides, and recheck fasteners and fluid level.

Troubleshooting quick tips

  • Spongy lever after bleeding: repeat bleed sequence and ensure reservoir never ran dry.
  • Fluid containing dark particles: system contamination; consider a full system flush and caliper inspection.
  • Persistent leak at banjo: replace crush washers and torque to spec.

Performing a proper brake fluid change and bleed on your 2017 Polaris Sportsman Touring 850 SP restores consistency and safety to your braking system. If you prefer shop assistance or need OEM replacement parts, MotoSport stocks parts specific to this MMY ATV to get you back on the trail quickly.

Related Shopping Categories

Shop Brake Fluid for a 2017 Polaris Sportsman Touring 850 SP ATV.

Shop Brake Bleeders for a 2017 Polaris Sportsman Touring 850 SP ATV.

Shop Brake Pads for a 2017 Polaris Sportsman Touring 850 SP ATV.

Shop Brake Lines for a 2017 Polaris Sportsman Touring 850 SP ATV.

Shop Brake Tools for a 2017 Polaris Sportsman Touring 850 SP ATV.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.