How to Bleed and Replace Brake Fluid on a 2021 Polaris Sportsman 570 EPS

Shop parts for a 2021 Polaris Sportsman 570 EPS ATV.

This MotoSport-exclusive guide walks you through flushing and bleeding the hydraulic brake system on a 2021 Polaris Sportsman 570 EPS. Follow these steps to maintain braking performance and safety. Read and follow all safety precautions, and consult your owner's manual for torque specs and fluid recommendations specific to your machine.

Tools & supplies

  • DOT 4 brake fluid (Polaris recommends DOT 4; use fresh, unopened fluid)
  • Clear plastic tubing that fits the bleeder nipples
  • Brake bleeder wrench or appropriate open-end wrench (typically 8mm or 10mm, check bleeder size)
  • Turkey baster or fluid syringe for reservoir removal
  • Clean rags and a drain pan
  • Rubber gloves and safety glasses
  • Torque wrench for caliper/reassembly fasteners
  • Jack and stands or ATV lift to keep wheels off ground (if required)
  • Assistant to operate brake lever/pedal for pressure bleeding

Model notes for the 2021 Polaris Sportsman 570 EPS

  • Factory system is a closed hydraulic circuit with ABS not present on base models; EPS refers to Electronic Power Steering only.
  • Master cylinder reservoir is on the handlebar for front brakes and a separate rear reservoir located near the rear brake master cylinder or integrated under the seat area depending on trim & accessory layout. Confirm which reservoir serves front vs. rear before starting.
  • Brake lines are routed to resist abrasion but inspect for chafing near racks and suspension pivots when replacing lines or re-routing.
  • Use DOT 4 only; mixing fluids or using DOT 5 silicone will damage seals and degrade performance.
  • ABS-equipped units (if your build has ABS accessory) require specific bleed procedures — this guide assumes non-ABS or conventional hydraulic calipers. If unsure, verify with VIN or service manual before proceeding.

Safety first

  • Work on a level surface with the engine off and parking brake engaged when applicable.
  • Brake fluid is corrosive to paint and plastics. Wipe spills immediately and protect finish with rags.
  • Wear gloves & eye protection. Dispose of old fluid per local regulations.

Step 1 – Prepare the ATV

  • Place the ATV on a stable lift or stands so wheels are off the ground if you plan to operate brakes fully. Turn handlebars to center for front caliper access.
  • Clean the master cylinder reservoir cap area to avoid contamination. Remove cap and diaphragm carefully.
  • Inspect reservoir fluid color — dark or contaminated fluid indicates the need for full replacement.

Step 2 – Remove old fluid from reservoir

  • Use a turkey baster or syringe to extract as much old fluid as possible from the reservoir(s) without allowing air into the system.
  • Refill reservoir with fresh DOT 4 fluid to the recommended level.

Step 3 – Bleeding order and general method

Standard bleeding order for Sportsman 570: farthest caliper first, then closer. For example, if bleeding front and rear separately:

  • For front system: right/front caliper (farthest from master), then left/front.
  • For rear: if single caliper, bleed that caliper last. If dual-rear, farthest first then closest.

Use a two-person pressure bleed or manual pump & hold method. Alternatively use a one-way vacuum bleeder to simplify and reduce air ingestion.

Step 4 – Bleeding procedure (manual pump & hold)

  1. Attach clear tubing to the bleeder nipple and place the other end into a container partially filled with clean fluid to prevent air return.
  2. Have an assistant slowly squeeze the brake lever or press the brake pedal several times and hold pressure on the lever/pedal.
  3. Open the bleeder nipple one-quarter to one-half turn to allow fluid and air out. Close the nipple before the assistant releases the lever/pedal.
  4. Repeat pump-hold-open-close cycles until you see only clear, uncontaminated fluid with no bubbles in the tubing.
  5. Keep reservoir topped between cycles to avoid introducing air.
  6. When complete, tighten bleeder nipple to spec (do not over-torque) and wipe excess fluid.

Step 5 – Vacuum or pressure bleeder option

  • Attach vacuum bleeder to the bleeder nipple per tool instructions, open nipple, and operate until clear fluid flows without bubbles.
  • If using a pressure bleeder on the reservoir, follow tool instructions and ensure the cap seals properly. Monitor reservoir level closely.

Step 6 – Replace fluid in both systems

  • Bleed all calipers in the proper order until the entire system is refreshed with clean DOT 4 fluid and no air is present.
  • Once finished, top reservoirs to the correct level and reinstall diaphragms and caps securely.

Step 7 – Final checks

  • Verify firm feel at lever & pedal with no sponginess. If spongy, repeat bleeding until firm.
  • Check for leaks at bleeder nipples, calipers, lines, and master cylinder. Tighten fasteners to spec as required.
  • Operate brakes at low speed to confirm performance before full use.
  • Properly dispose of old brake fluid and clean any spilled fluid from painted surfaces immediately.

Torque & hardware notes

  • Use manufacturer torque values for caliper and master cylinder mounting bolts. If you don't have specs on hand, note bolt sizes and consult your service manual or MotoSport service team.
  • Inspect bleeder nipples for corrosion; replace if rounded or leaking. Use new crush washers where applicable.

Troubleshooting

  • Persistent soft lever/pedal: likely air still present or internal master cylinder seal failure. Re-bleed; if problem persists, inspect master cylinder and calipers.
  • Fluid foaming or rapid aeration: stop, clean reservoir, ensure assistant is not allowing fluid to fall below minimum, and use proper bleed technique.
  • Contaminated fluid returns quickly: suspect caliper seals failing or internal contamination; consider caliper rebuild or replacement.

Maintenance tips specific to the Sportsman 570 EPS owner

  • Schedule brake fluid exchange every 2 years or sooner if you ride in wet or dusty conditions to avoid moisture buildup and decreased boiling point.
  • Check brake line routing near EPS components — ensure nothing rubs or interferes with steering travel.
  • If your machine has accessory racks or skid plates, remove or loosen as needed for access, then re-check line routing after reinstallation.
  • Keep a small bottle of DOT 4 in your service kit for topping off during long rides, but avoid storing open bottles long-term as moisture absorption degrades fluid.

When to call a pro

  • If you suspect internal ABS issues, master cylinder failure, or a leaking line that won't stop, have the unit inspected by a qualified technician.
  • If you cannot achieve a firm pedal after multiple bleed attempts, stop riding and seek professional service.

Performing a proper brake fluid replacement and bleed protects stopping power and prolongs the Sportman 570 EPS braking components. For replacement parts, hoses, replacement bleeder hardware, and DOT 4 fluid compatible with your model, MotoSport stocks parts tailored to your 2021 Polaris Sportsman 570 EPS — use the link above to get the right parts fast.

Related Shopping Categories

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Shop Brake Tools for a 2021 Polaris Sportsman 570 EPS 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.