How to Bleed and Replace Brake Fluid on a 2001 Yamaha Warrior

Shop parts for a 2001 Yamaha Warrior ATV.

This MotoSport-exclusive service guide covers step-by-step brake fluid replacement and bleeding for the 2001 Yamaha Warrior (YFM350). Follow these instructions for safe, reliable braking performance. If you’re uncomfortable with brake work, contact a qualified technician.

What you need

  • Brake fluid: DOT 4 recommended (use only fresh, sealed fluid; avoid mixing different DOT types)
  • Clear plastic tubing that fits over the bleeder nipple
  • Catch bottle for old fluid
  • Wrenches (typically 8mm or 10mm for bleeder screws and banjo bolts)
  • Disposable gloves, rags, and brake-safe paint cleaner
  • Turkey baster or syringe (for removing old fluid from reservoir)
  • Paper/plastic to protect plastics/paint from spills
  • Torque wrench for banjo bolt reassembly (if you remove lines)

Model notes & cautions specific to the 2001 Warrior

  • The 2001 Warrior has a single front and single rear hydraulic disc brake. There is no ABS system to complicate bleeding.
  • Brake components and banjo fittings on the Warrior are aluminum; avoid overtightening and use new crush washers if you open the banjo joints.
  • DOT 4 is recommended for higher boiling resistance in off-road use; always follow the spec on your brake master cylinder cap if discrepant.
  • Brake fluid damages paint and plastics. Protect bodywork and immediately clean any spills with brake cleaner and fresh water.
  • If the bike has sat for years or shows spongy brakes after fluid change, inspect caliper pistons, pads, hoses and the master cylinder for internal leakage or swelling.

Preparation

  • Park on level ground and secure the ATV. Remove the seat and side panels if needed for reservoir access.
  • Clean the reservoir cap area to prevent contamination when opening.
  • Wear gloves and eye protection. Keep rags handy for spills.
  • Check the master cylinder cap for the correct fluid type marking.

Step 1 – Remove old fluid from the reservoir

  • Open the reservoir cap and diaphragm. Use a syringe or turkey baster to remove most of the old fluid until noticeably darker fluid is gone.
  • Wipe the inside of the cap and top of the reservoir with a clean lint-free rag.
  • Refill the reservoir with fresh DOT 4 fluid to the recommended level but do not overfill.

Step 2 – Bleeding sequence & technique

Follow this standard sequence: bleed the brake caliper farthest from the master cylinder first, then the closer one. On the Warrior this usually means rear then front, but confirm with your bike’s layout.

  • Attach clear tubing to the bleeder nipple and submerge the other end into a catch bottle partially filled with fluid to prevent air reentry.
  • Have an assistant slowly pump the brake lever/pedal several times and hold pressure, or use a one-way bleeder tool if working alone.
  • Open the bleeder nipple about 1/4 turn so fluid and air escape into the tubing. When flow slows, close the nipple, then have the assistant release the lever/pedal. Repeat.
  • Keep the reservoir topped up throughout to avoid introducing air into the master cylinder.
  • Continue until you see clear, bubble-free fluid coming out and the lever/pedal feels firm.

Step 3 – Alternate methods

  • Gravity bleed: Open bleeder and let fluid flow slowly from caliper into tubing while keeping reservoir full. Slower, but effective if no assistant is available.
  • Pressure or vacuum bleeder: These tools speed the process and keep the system sealed. If using pressure, follow tool instructions closely.

Step 4 – Final checks and reassembly

  • Tighten bleeder screws to spec. Wipe all connections and inspect for leaks.
  • Top reservoir to the correct level, reinstall diaphragm and cap, and clean any spilled fluid.
  • If you removed banjo bolts, use new crush washers and torque to the correct value for your hardware.
  • Test lever/pedal feel at rest and during a slow test ride in a safe area. Expect slight improvement as new fluid fully circulates — but brakes must be firm before riding at speed.

Maintenance tips

  • Replace brake fluid every 1-2 years depending on use & exposure to moisture. Off-road riding with water crossings may require more frequent changes.
  • Keep a record of fluid changes and any brake work. Contaminated or dark fluid indicates a need for replacement.
  • Inspect brake hoses for swelling, cracks or soft spots; replace any suspect hose with DOT-compliant replacement lines.
  • If you encounter persistent sponginess after thorough bleeding, rebuild the master cylinder or caliper seals or consult a professional.

Disposal

Brake fluid is hazardous. Dispose of used fluid at an approved recycling or hazardous-waste facility; do not pour it down drains or onto soil.

Following these steps will keep your 2001 Yamaha Warrior braking system responsive and reliable. If unsure at any step, MotoSport recommends professional inspection and service.

Related Shopping Categories

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Shop Brake Tools for a 2001 Yamaha Warrior 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.