How to Bleed & Replace Brake Fluid on a 2020 Polaris Sportsman 570

Shop parts for a 2020 Polaris Sportsman 570 ATV.

This MotoSport service guide walks you through safely replacing and bleeding the hydraulic brake fluid on a 2020 Polaris Sportsman 570. It’s written for owners who want a reliable, professional-level result at home or in the shop. Follow each step exactly, use the correct fluid, and observe all safety cautions.

Overview & model notes

  • The 2020 Polaris Sportsman 570 uses a sealed hydraulic disc brake system with a single master cylinder reservoir feeding front & rear circuits (check your model's exact configuration; some variants have independent front/rear reservoirs).
  • Factory specification calls for DOT 4 brake fluid. Use fresh, unopened DOT 4 fluid only – do not mix with DOT 5 silicone fluid.
  • Reservoir is mounted near the handlebar/master cylinder assembly. On some trims the reservoir sight window may be on the side; confirm orientation before starting.
  • ABS is not present on standard Sportsman 570 models, but if your unit has electronic aids, consult Polaris service documentation before performing work that may trigger sensors.

Tools & materials

  • Fresh DOT 4 brake fluid (one or two 12 oz bottles depending on bleed volume)
  • Brake bleeder kit or clear tubing and a catch bottle
  • Wrenches for bleeder nipples (commonly 8mm or 10mm) and master cylinder cap
  • Torque wrench for caliper bolts (if removing calipers)
  • Clean lint-free rags, brake cleaner, and gloves
  • Safety glasses and a well-ventilated workspace
  • Small funnel or syringe for reservoir topping
  • Jack or stands to safely lift wheels if needed

Preparation & safety

  • Park on level ground, set parking brake, and remove ignition key to prevent accidental starts.
  • Clean around the master cylinder cap to prevent contamination when opened.
  • Protect painted surfaces – brake fluid will damage plastics and paint. Place rags or taped cardboard under work areas.
  • Wear eye protection & gloves. Dispose of old fluid per local regulations.

Step 1: Inspect system & drain old fluid

  1. Open master cylinder cap, remove diaphragm/foam insert, and inspect fluid color. Dark or contaminated fluid requires full replacement.
  2. Use a turkey-baster, syringe, or suction tool to remove as much old fluid from the reservoir as possible. Do not let debris fall into the reservoir.
  3. Top the reservoir with fresh DOT 4 fluid to the fill line to avoid introducing air when you begin bleeding.

Step 2: Wheel-by-wheel bleeding order

Standard bleeding order for best results on many Polaris ATVs is farthest wheel first working toward the master cylinder. For Sportsman 570 follow this sequence unless your machine has a different plumbing layout:

  • Rear caliper (if rear is single and farthest from master)
  • Front passenger-side caliper
  • Front driver-side caliper
  • Master cylinder (final reservoir topping/check)

Step 3: Manual two-person bleed method

  1. One person sits on the ATV or stands with foot on the brake lever/pedal, the other handles the bleeder nipple and reservoir level.
  2. Attach clear tubing to the bleeder nipple and route into a catch bottle partially filled with fresh fluid to prevent air re-entry.
  3. Loosen the bleeder nipple about a 1/4 turn. The helper depresses the brake slowly and holds it down. The bleeder handler opens the nipple to let fluid and air escape, then closes it before the helper releases the lever. Repeat pump-release until you see clean fluid with no bubbles in the tubing.
  4. After clearing that caliper, tighten the bleeder nipple to recommended snugness. Check reservoir fluid level – do not let it fall below the minimum while bleeding other calipers.

Step 4: One-person vacuum or pressure bleeding (preferred for consistency)

  1. Attach a vacuum bleeder to the caliper bleeder nipple or use a pressure bleeder on the master cylinder. Follow the tool manufacturer’s instructions.
  2. Operate the tool until clear, bubble-free fluid flows from the bleeder. Vacuum or pressure bleeding reduces the chance of introducing air and is faster for a thorough flush.
  3. Work through the bleeding order, keeping the reservoir topped.

Step 5: Flushing vs. just bleeding

  • If fluid has dark particles or you are doing scheduled maintenance, perform a full flush: remove old fluid from the reservoir, then pump fresh fluid through each caliper until clean fluid exits.
  • A partial bleed (only removing air) is acceptable after minor repairs, but fluid replacement on a 2-year interval is recommended for longevity and safety.

Step 6: Final checks & reassembly

  1. With all calipers bled, ensure bleeder nipples are tightened to spec snugness. Wipe any spilled fluid clean immediately.
  2. Top reservoir to proper level, reinstall diaphragm/foam insert, and secure master cylinder cap.
  3. Test lever/pedal firmness with the ATV stationary. Firm, consistent pressure indicates no air. If spongy, repeat bleeding sequence.
  4. Lower the ATV, test brakes at low speed in a safe area to confirm proper operation before riding normally.

Torque & hardware notes

  • If you remove calipers or brake hoses, use a torque wrench and Polaris torque specs where available. Tighten bleeder nipples finger-tight plus a small quarter-turn with a wrench – do not over-torque.
  • Replace any rubber hoses that are cracked, swollen, or older than recommended service intervals.

Troubleshooting

  • Persistent spongy lever: check for air still in system, collapsed hose, or master cylinder issues. Repeat bleeding and inspect hoses.
  • Brake drag after bleeding: ensure bleeder nipple fully closed, caliper pistons not seized, and no overfilled reservoir that prevents pistons from retracting.
  • Fluid leaks: replace seals, banjo bolts, or hoses as needed and re-bleed after repairs.

Maintenance tips specific to the 2020 Sportsman 570 owner

  • Rotate brake fluid every two years or sooner if used in wet/muddy conditions often encountered by ATV riders.
  • Inspect master cylinder reservoir boot & cap seal for aging — failing seals can draw moisture into the system and accelerate fluid degradation.
  • If your Sportsman 570 is used for towing or heavy loads, inspect pads for accelerated wear and monitor rotor condition for heat-related warping.
  • Keep a small sealed bottle of DOT 4 in your toolbox for roadside top-offs — only for emergencies and not for long-term topping without a proper bleed afterward.

Disposal & final safety

  • Do not pour used brake fluid on the ground or down drains. Collect and dispose of old fluid at an approved recycling or hazardous-waste facility.
  • After service, verify brake light switches and safety interlocks operate normally before riding.

Follow these steps and your 2020 Polaris Sportsman 570 will have a fresh, properly bled brake system ready for confident riding. If you prefer professional service, MotoSport technicians can assist with a complete brake system inspection and fluid replacement.

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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.