How to Bleed & Replace Brake Fluid on a 2015 Polaris Scrambler 850

Shop parts for a 2015 Polaris Scrambler 850 ATV.

This MotoSport-exclusive service guide walks you through replacing and bleeding the brake fluid on a 2015 Polaris Scrambler 850 (MMY: Polaris;SCRAM850;2015). The Scrambler 850 uses separate master cylinders for front and rear brakes — a right-handlebar master cylinder for the front and a foot-pedal master cylinder for the rear — so each circuit is serviced independently.

What you need

  • DOT 4 brake fluid (new, unopened)
  • Clear vinyl tubing long enough to fit over bleed nipples
  • Catch bottle (clean, disposable) with a small amount of old fluid or mineral oil to reduce air intake
  • Appropriate-size wrench for bleed nipples (typically 8mm – 10mm)
  • Phillips or flat screwdriver for reservoir caps (as applicable)
  • Clean lint-free rags and isopropyl alcohol or brake parts cleaner
  • Latex or nitrile gloves and eye protection
  • Bike stand or blocks to keep ATV level and wheels off the ground as needed

Safety & prep

  • Work on a cool machine. Brake fluid is hygroscopic — keep containers capped.
  • Protect painted surfaces — DOT fluid damages paint. Immediately rinse any spills with water and clean with alcohol.
  • Dispose of old fluid per local hazardous-waste rules.
  • Park ATV on level surface with parking brake off. If lifting wheels, ensure stable stands.

Notes specific to the 2015 Scrambler 850

  • Front and rear systems are independent: you will have two reservoirs to service. Do not mix fluids between systems if using separate types — use DOT 4 for both unless OEM specifies otherwise.
  • There is no combined ABS module on this model; bleeding is mechanical at each caliper.
  • Master cylinder reservoir caps may have a diaphragm; avoid stretching or damaging it when opening.
  • Caliper bleed screws are exposed but can pick up dirt — clean thoroughly before opening to prevent contamination entering the system.

Step-by-step: Replace & bleed the fluid

1. Top-off & drain approach (recommended for full replacement)

  1. Remove reservoir cap and diaphragm on one circuit (start with the system farthest from the master cylinder if you treat as single system; for the Scrambler, treat front and rear separately).
  2. Use a turkey-baster or syringe to remove most old fluid from the reservoir. Refill to the "MAX" line with fresh DOT 4 fluid.
  3. Attach clear tubing to the caliper bleed nipple and route into catch bottle partially filled to submerge tubing end to prevent air re-entry.
  4. Have an assistant slowly depress and hold the brake lever or pedal while you open the bleed nipple about a quarter to a half turn. Fluid and bubbles will flow into the tubing. Close the nipple before the assistant releases the lever/pedal. Repeat until no bubbles appear and fluid runs clear.
  5. Keep reservoir level topped up during the process to avoid drawing air into the master cylinder.
  6. When finished, tighten bleed nipple to spec (snug; avoid over-torquing), wipe clean, re-install diaphragm and cap.
  7. Repeat same procedure on the other brake circuit.

2. Two-person vacuum or pressure bleed alternative

  • Use a hand-vac or pressure-bleeder tool on the reservoir per tool instructions. This speeds purging and reduces assistant dependence. Always keep reservoir capped with supplied adapter and monitor fluid level.

3. One-person pump-and-hold method

  1. Attach tubing & catch bottle, open the bleed screw.
  2. Operate lever/pedal repeatedly to push old fluid out; use a clamp or strap to hold lever/pedal in the applied position and close the nipple. Release, then repeat until fluid is clean.
  3. Maintain reservoir level throughout.

Bleeding order & tips

  • Because the Scrambler 850 has independent circuits, bleed each circuit independently from its caliper(s) to the master cylinder.
  • For systems with two calipers (if aftermarket setups exist), bleed the caliper farthest from the master cylinder first.
  • Always top the reservoir during the process to prevent air entry into the master cylinder.
  • Replace reservoir diaphragm or cap if cracked or degraded.
  • After bleeding, pump the brake to confirm firm feel before riding. If spongy, repeat bleeding.

After service checks

  • Check for leaks at bleed nipples, banjo bolts and reservoir connections after a short test ride.
  • Confirm pedal/lever travel and braking performance at low speed before normal riding.
  • Record fluid change in your maintenance log. Brake fluid should generally be replaced every 1–2 years depending on use & exposure to water.

Troubleshooting

  • Persistent spongy lever after bleeding: likely trapped air. Repeat bleeding and ensure reservoir never runs low.
  • No fluid flow at caliper: verify bleed screw is fully open and tubing is not blocked or kinked.
  • Contaminated or dark fluid despite bleeding: perform a full reservoir drain and repeat until fluid clears.

Follow these steps and precautions to safely replace and bleed brake fluid on your 2015 Polaris Scrambler 850. When in doubt, contact a qualified ATV technician or MotoSport service desk for model-specific assistance.

Related Shopping Categories

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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.