How to Bleed & Replace Brake Fluid on a 2006 Polaris Sportsman 90
Shop parts for a 2006 Polaris SPORTS90 ATV.
This MotoSport proprietary guide walks you through safely draining, flushing, and bleeding the brake system on a 2006 Polaris Sportsman 90. Follow every step carefully, use the right fluid, and take model-specific notes below into account before you begin.
Tools & Supplies
- DOT 3 or DOT 4 brake fluid (do not use DOT 5 silicone)
- Clear vinyl tubing that fits the caliper bleed nipple
- Clean catch bottle or container
- Wrench for bleed nipple (usually 8 mm or 10 mm; verify by fit)
- Small funnel, turkey baster or siphon pump
- Clean rags, gloves, and eye protection
- Jack or ramps and wheel blocks (if removing wheels)
- Brake-clean spray and small wire brush (for nipples & fittings)
- Torque wrench (for wheel/fastener reassembly)
Safety & Prep
- Work on a level surface with ignition off and key removed.
- Block wheels and secure lift so the machine cannot roll.
- Protect painted surfaces from brake fluid — it damages paint.
- Never reuse brake fluid that has been left open to air for long — it absorbs moisture.
- Confirm brake fluid type in your owner’s manual; DOT 3 and DOT 4 are commonly used but do not mix DOT 5.
Model Notes for the 2006 Polaris Sportsman 90
- The Sportsman 90 is a youth/utility 90cc ATV with a compact hydraulic braking system. Reservoirs are small — keep it topped up throughout the procedure to prevent air from entering the system.
- Some 2006 Sportsman 90s use a single master cylinder feeding both front and rear circuits through distribution lines. Identify the reservoir and label hoses if necessary before disconnecting anything.
- Master cylinder reservoir is often translucent plastic under the handlebars; clean the cap area before opening to avoid contamination.
- Many service tasks on this model are simpler with wheels removed for better access to bleed nipples; use jack stands and follow proper lifting points.
Step-by-Step: Drain & Replace Brake Fluid
- Clean the reservoir cap area then remove cap and diaphragm. Inspect fluid color and level. If fluid is dark or contaminated, proceed.
- If desired, remove the old fluid from the reservoir using a turkey baster or suction pump. Dispose of old fluid properly.
- Refill the reservoir with new DOT 3 or DOT 4 fluid to the fill line. Keep the cap off but protected to prevent debris entry.
- Start bleeding at the caliper or wheel cylinder farthest from the master cylinder and work toward the closest. Typical sequence: rear (if separate), then front or left/right depending on hose routing — choose the furthest first.
- Attach clear tubing to the bleed nipple and place the other end into a catch bottle half-filled with clean fluid to prevent air re-entry.
- Have a helper slowly pump the brake lever or pedal several times and hold pressure. Open the bleed nipple about a quarter turn to let fluid and air escape into the tubing. Close the nipple before the helper releases pressure. Repeat until you see clear, bubble-free fluid.
- Keep reservoir topped up throughout. Never let it drop low enough to draw air into the system.
- Repeat the process at each bleed nipple in the correct sequence until all lines show clean fluid and no air bubbles.
- After final bleed, torque bleed nipples to proper snugness; avoid over-tightening. Wipe all fittings and the area clean. Replace diaphragm and cap on the reservoir.
- Operate the brake lever/pedal several times to confirm a firm feel. If spongy, repeat bleeding cycle.
- Reinstall wheels if removed, torquing lug nuts to spec. Lower ATV and perform a low-speed brake test in a safe area to verify performance.
Bench Bleeding & Full Flush Option
If the system is heavily contaminated, consider a full flush: repeatedly draw old fluid from the reservoir and refill with fresh fluid until expelled fluid runs clear from the bleed nipples. For thorough results, bench-bleed the master cylinder before reconnecting lines if you remove it from the frame.
Troubleshooting
- Spongy pedal after bleeding: likely air remains. Re-bleed, using longer hold times and ensuring reservoir never empties.
- Persistent leaks: inspect hose clamps, lines, and caliper seals. Replace any cracked hoses or leaking seals.
- Brake drag after bleeding: check caliper pistons and slide pins for corrosion or contamination; clean and lubricate per service manual recommendations.
Maintenance Tips & Disposal
- Replace brake fluid every 1-2 years or per riding conditions to prevent moisture buildup and corrosion.
- Store brake fluid sealed and discard any fluid that appears cloudy or contaminated.
- Dispose of used brake fluid at an approved hazardous-waste facility or automotive collection point.
When to Seek Professional Help
If you encounter persistent leaks, internal master cylinder failure, damaged calipers, or if braking performance remains poor after proper bleeding, stop and have a qualified technician inspect the system. Brakes are critical to safety; when in doubt, have professionals diagnose and repair the issue.
Related Shopping Categories
Shop Brake Fluid for a 2006 Polaris SPORTS90 ATV.
Shop Brake Bleeders for a 2006 Polaris SPORTS90 ATV.
Shop Brake Pads for a 2006 Polaris SPORTS90 ATV.
Shop Brake Lines for a 2006 Polaris SPORTS90 ATV.
Shop Brake Tools for a 2006 Polaris SPORTS90 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.