How to Bleed & Replace Brake Fluid on a 2016 Polaris Sportsman 850

Shop parts for a 2016 Polaris Sportsman 850 ATV.

This MotoSport guide gives a clear, step-by-step procedure for replacing and bleeding the hydraulic brake fluid on a 2016 Polaris Sportsman 850. Follow safety steps, use the correct fluid, and complete the bleed sequence so brakes feel firm and consistent. If your ATV is equipped with ABS or an electronic brake module, read the model notes below before starting.

Tools & materials

  • DOT 4 brake fluid (or the specification listed in your owner’s manual)
  • Clear tubing that fits snugly over bleed nipples
  • Catch bottle for old fluid
  • Brake bleeder wrench or appropriately sized box wrench
  • Turkey baster or fluid syringe (to remove old fluid from reservoir)
  • Clean lint-free rags and isopropyl alcohol
  • Jack or stands to stabilize the ATV (if needed to access calipers)
  • Gloves and eye protection

Prep and safety

  • Work on a level surface, engine off, parking brake engaged and key removed.
  • Wear gloves & eye protection. Brake fluid damages paint & plastics — wipe spills immediately.
  • Keep the master cylinder reservoir cap and diaphragm clean. Do not allow dirt to enter the reservoir.
  • If your unit has ABS, follow the model notes below before draining fluid; ABS systems can trap old fluid and need specific procedures.

Step 1 – Inspect and remove old fluid from reservoir

  1. Locate the front brake master cylinder reservoir (usually on the handlebar) and rear reservoir if separate. Clean the exterior thoroughly.
  2. Remove the cap and diaphragm. Using a turkey baster or fluid syringe, remove as much old fluid as possible from the reservoir.
  3. Top the reservoir with fresh DOT 4 fluid to prevent air entry while you work.

Step 2 – Identify bleed order

Bleed starting with the brake caliper farthest from the master cylinder and finish with the nearest. On most Sportsman 850 layouts this means:

  • 1st: Rear passenger side (farthest)
  • 2nd: Rear driver side
  • 3rd: Front passenger side
  • 4th: Front driver side (nearest)

If your bike has a different plumbing layout, adapt the sequence so the most remote caliper is bled first.

Step 3 – Bleeding procedure (single-person method)

  1. Attach clear tubing to the bleeder nipple on the caliper and insert the other end into a catch bottle partially filled with old fluid to prevent air return.
  2. Loosen the bleeder nut about a quarter to half turn. Do not remove it completely.
  3. Squeeze the brake lever or press the brake pedal slowly until resistance begins and then hold it down. If working single-handed, a one-way bleed valve tool helps trap pressure.
  4. Open the bleeder slightly to allow fluid to flow until the lever/pedal reaches the floor, then close the bleeder before releasing the lever/pedal to avoid sucking air in.
  5. Repeat this squeeze-open-close cycle until you see clean, bubble-free fluid coming out and the lever/pedal feels firm.
  6. Keep the reservoir topped with fresh fluid during the entire process to prevent air from entering the system.

Step 4 – Two-person (faster) method

  1. Partner holds steady pressure on lever/pedal while you open the bleeder to let fluid and air escape, then close the bleeder before they release pressure. Repeat until clear fluid appears.
  2. Always close the bleeder before the lever/pedal is released to prevent drawing air back into the system.

Step 5 – Finish up

  • When all calipers are bled in sequence, top the reservoir to the proper level, reinstall the diaphragm and cap, and tighten bleeder nipples to spec (snug, do not over-torque).
  • Clean any spilled fluid from painted or plastic surfaces with water and mild detergent, then wipe dry.
  • Test the brakes at low speed in a safe area to confirm firmness and consistent braking.
  • Properly dispose of used brake fluid per local regulations.

Model-specific notes for the 2016 Polaris Sportsman 850

  • The Sportsman 850 uses a hydraulic brake system that responds to DOT 4 fluid; confirm the exact spec in your owner’s manual if unsure. Using the wrong fluid can damage seals.
  • Some 2016 Sportsman 850 models were equipped with an optional ABS or traction control module. ABS-equipped units can trap fluid and air in the hydraulic control unit; simple caliper bleeding may not purge all air. If you have ABS, plan on a full system bleed that may require cycling the ABS pump or a dealer-level scan tool to command the module during bleeding. If you are not sure whether your unit has ABS, check for wheel speed sensors at the hubs and an electronic module under the bodywork before starting.
  • Avoid prolonged exposure of the reservoir diaphragm to open air — too much time with the cap off can let moisture into the system and reduce fluid life.
  • If you notice spongy brakes after bleeding, repeat the bleed sequence and verify there are no soft hoses, leaking fittings, or internal caliper seal failures.
  • Replace any flexible brake hoses that are cracked, swollen, or leaking. Hoses older than manufacturer service intervals should be renewed to maintain consistent pedal feel.

Troubleshooting

  • Persistent soft pedal after several bleeds: check hoses, caliper pistons, master cylinder seals, and ABS module requirements.
  • Brake drag after bleeding: ensure caliper pistons return fully and that bleeder caps are reinstalled; check caliper slides/pins for smooth operation.
  • Air returns after release of pressure: make sure bleeder is closed before releasing lever/pedal and reservoir level never drops below the minimum while bleeding.

Maintenance tips

  • Change brake fluid every 1-2 years or sooner if it appears dark or contaminated.
  • Inspect calipers, pads, and rotors while you have lines and wheels exposed.
  • Keep a small sealed bottle of DOT 4 on hand for topping off in the field; always reseal the bottle to prevent moisture absorption.

Keep this MotoSport procedure with your maintenance notes and schedule regular inspections to preserve stopping performance and safety on your Sportsman 850.

Related Shopping Categories

Shop Brake Fluid for a 2016 Polaris Sportsman 850 ATV.

Shop Brake Bleeders for a 2016 Polaris Sportsman 850 ATV.

Shop Brake Pads for a 2016 Polaris Sportsman 850 ATV.

Shop Brake Lines for a 2016 Polaris Sportsman 850 ATV.

Shop Brake Tools for a 2016 Polaris Sportsman 850 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.