How to Bleed & Replace Brake Fluid on a 2004 Suzuki Eiger 400 2X4 SEMI-AUTO

Shop parts for a 2004 Suzuki Eiger 400 2X4 SEMI-AUTO ATV.

This MotoSport-exclusive service guide walks you through safely flushing and bleeding the brake system on the 2004 Suzuki Eiger 400 2X4 SEMI-AUTO. Follow these steps carefully, use quality tools and parts, and observe all safety precautions. This procedure is specific to the Eiger's simple hydraulic system (no ABS) and covers both the front caliper(s) and the rear brake circuit.

What you’ll need

  • Correct brake fluid (see notes below & owner’s manual) and a sealed spare bottle
  • Brake bleeder kit or clear tubing and a catch bottle
  • Wrench set (open-end or flare nut wrench for bleed nipples)
  • Phillips & flat screwdrivers; pliers
  • Shop rags, nitrile gloves, safety glasses
  • Clean syringe or turkey baster (to remove old fluid from reservoir)
  • Jack or ramps and wheel chocks if you need to access calipers
  • Torque wrench for reassembly where applicable

Safety & prep

  • Work on a level surface, engine off, key removed.
  • Protect painted surfaces – brake fluid damages paint. Keep rags under the reservoir and calipers.
  • Wear eye protection & gloves. Brake fluid is corrosive.
  • If the system is heavily contaminated or dark, perform a full fluid change rather than a simple bleed.

Brake fluid type & model notes

The Eiger 400 uses a conventional non-ABS hydraulic system. Suzuki staff generally specify DOT-compliant fluid in the owner’s manual; if the manual is unavailable, use DOT 3 or DOT 4 fluid that meets motorcycle ATV specifications and is fresh (sealed bottle). Avoid mixing mineral-based fluids with DOT fluids. If in doubt, consult your MotoSport parts lookup or your service records before choosing fluid.

Step 1 – Inspect system

  • Check reservoir level – remove the cap and diaphragm, inspect for dark, dirty fluid or contamination.
  • Inspect calipers, lines and hoses for leaks, cracks, or soft spots. Replace damaged hoses before bleeding.
  • Note whether the system has a single combined reservoir for front & rear or separate circuits; the Eiger commonly uses a shared master cylinder with multiple outlets. Keep the master cap closed except when adding fluid.

Step 2 – Remove old fluid from reservoir

  • Use a syringe or turkey baster to remove as much old fluid from the reservoir as possible. Dispose of fluid properly.
  • Refill the reservoir with fresh fluid to the recommended level to avoid introducing air during the procedure.

Step 3 – Bleeding order

For the Eiger 400, follow this general order: bleed the caliper farthest from the master cylinder first, then the nearer caliper. If your machine has a separate rear circuit, bleed the rear after fronts, or follow the sequence printed on the master cylinder cap if present.

Step 4 – Bleed using one of these methods

Choose the method you’re comfortable with. Always keep the reservoir topped up during the entire process.

  • Gravity bleed – Loosen bleed nipple slightly and allow fluid to drip into a catch bottle. Slow but simple; good for minor air removal.
  • Pressure or vacuum bleeder – Recommended for a faster, cleaner job. Attach the device to the reservoir (pressure) or the bleed nipple (vacuum) and follow manufacturer instructions.
  • Manual pump – two-person – One person pumps the brake lever/pedal gently; the other opens the bleed nipple to let fluid/air escape then closes it before the lever is released. Repeat until fluid runs clear and bubble-free.

Bleeding procedure (two-person manual method)

  1. Attach clear tubing to the bleed nipple and submerge the other end in a small bottle partially filled with clean brake fluid to prevent air re-entry.
  2. With helper gently holding the brake lever/pedal, have them slowly squeeze to roughly 3/4 travel and hold it there.
  3. Open the bleed nipple a 1/4 to 1/2 turn to allow fluid and air to escape. Close the nipple before the helper releases the lever.
  4. Top up the master cylinder reservoir immediately after each cycle to keep the line full of fluid and prevent new air from entering.
  5. Repeat until clear, bubble-free fluid flows and the lever feel is firm.
  6. Torque the bleed nipple to factory spec if available (snug tight if spec unknown) and wipe clean.
  7. Repeat for every caliper/bleed point in the correct sequence.

Step 5 – Final flush of reservoir

When bleeding is complete, remove remaining old fluid from the reservoir and refill with fresh fluid to the proper level. Seal the cap securely. Pump the brake lever/pedal several times to confirm firm, consistent feel.

Step 6 – Clean up & test ride

  • Thoroughly clean any spilled fluid from painted areas & components.
  • Check for leaks at bleed nipples, lines, and calipers after a short ride. Re-torque caliper bolts and bleed nipples if necessary.
  • Perform a low-speed operational test in a safe area to confirm braking performance before normal use.

Common issues & troubleshooting

  • If lever/pedal remains spongy after thorough bleeding, inspect master cylinder seals, caliper pistons, and hoses for internal degradation; soft/swollen hoses or damaged seals can allow air or expand under load — replace as needed.
  • Stubborn air pockets: Elevate the wheel or caliper to help trapped air migrate toward the bleed nipple.
  • Contaminated system: If fluid is dark, gummy, or compromised, a multiflush (several fill/flush cycles) or component overhaul may be required.

MotoSport model-specific notes for the 2004 Eiger 400 2X4 SEMI-AUTO

  • The Eiger 400 is a simple, rugged ATV with a compact braking system designed for trail use; it has no ABS electronics to complicate bleeding.
  • Semi-auto transmission means you may frequently use engine braking; ensure rear brake feel is prioritized if you ride in steep terrain often.
  • Front brake components are more exposed to trail debris & mud. Inspect caliper slide bosses and dust seals after cleaning and bleeding.
  • If your machine still uses original rubber brake hoses, consider replacing them with fresh hoses if older than 8-10 years or showing signs of wear; this improves pedal feel and safety.
  • Always use new crush washers on banjo bolts and inspect hardware condition when servicing brake lines.

Maintenance interval recommendation

For reliable stopping performance, plan a brake fluid change and bleed every 1-2 years depending on use & environment. Heavy trail use, water crossings, or harsh conditions warrant more frequent service.

Disposal

Used brake fluid is hazardous waste. Collect and dispose of it at an approved recycling or hazardous waste facility per local regulations.

Performing a clean, complete brake fluid replacement and bleed will restore firm, predictable braking on your 2004 Suzuki Eiger 400 2X4 SEMI-AUTO. If you encounter persistent problems after bleeding, MotoSport recommends a professional inspection to verify master cylinder and caliper integrity.

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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.