How to Bleed & Replace Brake Fluid on a 1999 Honda TRX400 Foreman 4X4

Shop parts for a 1999 Honda TRX400 Foreman 4X4 ATV.

This MotoSport-exclusive guide walks you through safely replacing and bleeding brake fluid on a 1999 Honda TRX400 Foreman 4X4. Follow every step, use quality parts & fluids, and observe shop safety.

What you’ll need

  • DOT 3 brake fluid (Honda recommends DOT 3 for this model)
  • Clear hose that fits bleed nipples
  • Catch bottle for old fluid
  • Wrenches for bleed nipples (open-end) and master cylinder cap
  • Clean shop rags & brake parts cleaner
  • Gloves & eye protection
  • Helper (recommended) or a one-person vacuum or pressure bleeder
  • Torque wrench (for re-assembly to specified tightness where required)

Model notes — 1999 TRX400 Foreman 4X4

  • The Foreman uses DOT 3 brake fluid. Do not mix DOT 5 (silicone) with DOT 3/4 systems.
  • The TRX400 has separate hand (front) and foot (rear) brake master cylinders; bleed and replace fluid in each circuit separately.
  • There is no factory ABS; bleeding is a straightforward hydraulic system.
  • Brake lines and hardware on older Foremans can be seized or corroded; inspect hoses, banjos, and nipples for wear or swelling and replace if suspect.
  • Brake fluid should be replaced every 1-2 years or sooner if contaminated, dark, or hygroscopic absorption is suspected.

Preparation

  • Park on level ground, set parking brake, and remove key. Secure the ATV on stands so wheels can turn freely.
  • Clean around master cylinder caps and bleed nipples to prevent contamination.
  • Open the master cylinder reservoir(s) slowly. Top with fresh DOT 3 fluid and leave the cap loosely in place to keep out dirt.
  • Label circuits if needed (hand/front vs. foot/rear) so you don’t mix lines while bleeding.

Bleeding order

Use the general rule – bleed the wheel farthest from the master cylinder first, progressing to the nearest. For the TRX400 Foreman 4X4 that means:

  1. Rear passenger (farthest)
  2. Rear driver
  3. Front passenger
  4. Front driver (closest)

Manual two-person bleeding method

  1. Have your helper sit on the ATV to apply gentle brake pressure when requested (prevents pedal/lever droop while bleeding).
  2. Attach clear hose to the bleed nipple and place the other end into a catch bottle partially filled with fresh fluid to avoid air re-entry.
  3. Open the bleed nipple about a quarter turn.
  4. Helper slowly applies steady pressure to the brake lever or pedal until it reaches near-firm. You will see old fluid & air in the hose.
  5. Close the bleed nipple while pressure is held. Helper releases the lever/pedal. Repeat until clear, bubble-free fluid exits and new fluid appears in the bottle.
  6. Keep the master reservoir topped during the entire process to prevent drawing air into the system.
  7. Once clear fluid flows, tighten bleed nipple securely (snug to spec) and wipe clean.
  8. Repeat for each wheel in the bleed order, then final-check lever/pedal feel and reservoir level.

One-person vacuum or pressure bleeder method

  1. Follow manufacturer instructions for the tool, attach to master reservoir or caliper as directed.
  2. Operate tool to draw fluid from each caliper in the bleed order until clear, bubble-free fluid appears.
  3. Keep reservoir topped and finish by tightening bleed nipples and confirming firm brake feel.

Special tips & cautions

  • Never reuse drained brake fluid. Dispose of it in accordance with local regulations.
  • Brake fluid damages paint — clean spills immediately with brake cleaner and water.
  • If you feel sponginess after bleeding, repeat bleeding procedure or check for leaks, collapsed hoses, or a failing master cylinder.
  • Inspect rubber lines for swelling or cracking; replace any suspect hoses before finalizing the bleed.
  • If calipers have internal air pockets, cycling wheel position or using a bench-bleed procedure on separate master assemblies may be necessary.

Post-service checklist

  • Confirm reservoir levels are within the correct range and caps are tightened.
  • Check for leaks at bleed nipples, hose connections, and banjo bolts after a short test ride.
  • Re-torque any wheel, caliper, or brake hardware to Honda specifications.
  • Test brakes at low speed in a safe area to confirm firm, consistent stopping before regular use.

Following these MotoSport-specific steps will leave your 1999 TRX400 Foreman 4X4 with a clean brake system and reliable stopping performance. If you encounter seized fittings, leaking components, or persistent softness, replace the affected parts or consult a technician.

Related Shopping Categories

Shop Brake Fluid for a 1999 Honda TRX400 Foreman 4X4 ATV.

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Shop Brake Lines for a 1999 Honda TRX400 Foreman 4X4 ATV.

Shop Brake Tools for a 1999 Honda TRX400 Foreman 4X4 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.