How to Bleed and Replace Brake Fluid on a 2017 Polaris Sportsman 850 HIGH LIFTER

Shop parts for a 2017 Polaris Sportsman 850 HIGH LIFTER ATV.

This MotoSport-exclusive guide walks you through safely draining, flushing, and bleeding the brake system on a 2017 Polaris Sportsman 850 HIGH LIFTER (MMY). Follow these steps and model-specific notes to restore firm, reliable brakes.

Model-specific notes for the 2017 Sportsman 850 HIGH LIFTER

  • The HIGH LIFTER package raises ground clearance and uses heavier-duty suspension components; extended travel can shift brake line routing and mounting points compared to base models. Inspect hoses for rubbing at extended suspension positions.
  • Many Sportsman 850s use standard DOT brake fluid (DOT 3/DOT 4). Confirm the correct DOT rating in your owner's manual or the reservoir cap marking before service. Never mix DOT types unless specifically permitted by the manual.
  • Polaris machines can have separate front & rear reservoirs or a combined system depending on options; identify your reservoir layout so you drain and refill the proper circuit(s).
  • Parking brake components, caliper parking mechanisms, and mud-shedding design on High Lifter machines make it important to clean calipers and pivot areas before bleeding to avoid contamination and binding.

Tools & supplies

  • Correct DOT brake fluid (confirm DOT 3 or DOT 4 per reservoir)
  • Clear plastic tubing that fits bleeder nipples
  • Catch bottle for old fluid
  • Wrenches sized to caliper bleeder nipples
  • Brake cleaner, clean rags, gloves, eye protection
  • Turkey baster or fluid transfer pump (for draining reservoirs)
  • Optional: vacuum bleeder or pressure bleeder for faster, cleaner bleeding
  • Service jack or ramps and stands to safely lift and support the ATV

Safety & preparation

  • Work on a flat, stable surface with the ATV in park/neutral and engine off; block wheels to prevent rolling.
  • Wear eye protection and gloves. Brake fluid damages paint & plastics — clean spills immediately.
  • Keep the reservoir caps closed until you're ready to refill to minimize moisture contamination.
  • If you're unsure of the reservoir type or DOT rating, stop and consult the owner's manual before proceeding.

Step 1 – Inspect and clean

  • Wash the area around reservoirs and calipers to prevent dirt entering the system.
  • Check hoses, fittings, and caliper boots for cracks, leaks, or damage. Replace any compromised parts before bleeding.

Step 2 – Drain old fluid from reservoirs

  • Remove the reservoir caps (and diaphragms if present). Use a turkey baster or fluid pump to remove as much old fluid as possible.
  • Dispose of old fluid responsibly — do not pour it down drains.

Step 3 – Refill with fresh fluid

  • Fill the reservoir to the MAX line with the specified DOT fluid. Keep the cap loosely in place so air can escape but contamination is limited.

Step 4 – Bleeding sequence – general rule

Bleed from the caliper farthest from the master cylinder first, then proceed to the next-farthest, finishing with the caliper closest to the master cylinder. On most Sportsman setups that means: rear caliper first, then right front, then left front (confirm by locating master cylinder/reservoir on your machine).

Step 5 – Manual bleed procedure (recommended for one-person jobs)

  1. Fit clear tubing over the bleeder nipple and route it into a catch bottle partially filled with fresh fluid to prevent air re-entry.
  2. Have a helper slowly press the brake lever/pedal repeatedly and hold it down. While held, open the bleeder nipple about 1/4 turn until fluid & air bubbles flow into the tube, then close the nipple before the helper releases the lever. Repeat until only clean fluid with no air bubbles appears.
  3. Top the reservoir frequently to prevent it from running dry — running dry draws air into the entire system.
  4. Work through the bleed sequence: farthest caliper to nearest. After bleeding each caliper, ensure its bleeder nipple is snug but do not over-torque.

Step 6 – Alternative: vacuum or pressure bleeder (faster, cleaner)

  • Attach the device per manufacturer instructions. Operate until clear, bubble-free fluid flows from each bleeder in the correct sequence. Maintain reservoir level during the process.

Step 7 – Final top-off, checks & cleanup

  • After bleeding all calipers, top the reservoir to the MAX line and reinstall caps and diaphragms securely.
  • Clean any spilled brake fluid with brake cleaner and rinse painted surfaces with water; inspect for leaks at bleeders, banjo bolts, and hose fittings.
  • Pump the brake lever/pedal to confirm a firm feel before riding. If it feels spongy, repeat bleeding until firm.
  • Test ride cautiously at low speed to verify braking performance and re-check for leaks after the test ride.

Maintenance intervals & best practices

  • Brake fluid absorbs moisture over time. Replace brake fluid every 1 to 2 years, or sooner if you ride in wet/muddy conditions or if the fluid appears dark or contaminated.
  • Inspect hoses, caliper boots, and lines whenever you service brakes; High Lifter suspension travel can accelerate wear on lines and connections if not inspected regularly.
  • Keep a small spare bottle of the correct DOT fluid in your shop for topping off — never substitute DOT 5 silicone fluid unless your system is specifically designed for it.

Troubleshooting

  • Persistent spongy lever after multiple bleeds: suspect trapped air in master cylinder, a leaking component, or contaminated master cylinder. Consider bench-bleeding the master cylinder or replacing faulty parts.
  • Leaking bleeder: replace the bleeder screw or caliper if threads/ports are damaged. Always use new copper crush washers on banjo fittings when disturbed.
  • Soft pedal that firmed up then softened: check for reservoir leaks or a hose with an internal collapse allowing fluid to bypass under pressure.

Follow this MotoSport-specific guide to keep your 2017 Polaris Sportsman 850 HIGH LIFTER stopping reliably. If you find corrosion, damaged hoses, or persistent problems, replace components or consult a qualified technician for a professional inspection and repair.

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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.