How to Bleed & Replace Brake Fluid on a 1997 Honda TRX300 FOURTRAX 2X4

Shop parts for a 1997 Honda TRX300FOUR ATV.

This proprietary MotoSport guide walks you through safely replacing and bleeding the brake fluid on your 1997 Honda TRX300 FOURTRAX 2x4. Read each step before starting and gather tools and supplies. If you aren't comfortable with brake work, have a qualified technician perform the service.

What to know about the 1997 TRX300 FOURTRAX 2x4

  • Verify brake types before starting: many TRX300 FOURTRAX 2x4s use a hydraulic front disc brake and a mechanically actuated rear brake (drum/cable). The rear cable/drum is typically not hydraulic or bleeder-equipped. Confirm your machine has hydraulic components to service.
  • Brake fluid specification: use DOT 3 or DOT 4 as specified by Honda. Use fresh, unopened fluid from a sealed container and avoid contamination with water or other fluids.
  • Original equipment and wear points: rubber hoses and soft lines on older machines can deteriorate. Inspect hoses, master cylinder, calipers, and bleeder nipples for corrosion, cracking or leaks before and after bleeding.
  • Master cylinder reservoir access: the TRX300 reservoir is smallkeep it topped during the procedure to prevent drawing more air into the system.

Tools & Supplies

  • DOT 3 or DOT 4 brake fluid (fresh)
  • Appropriate open-end or box wrenches for bleeder nipples (commonly 8mm or 10mm)
  • Clear plastic hose that fits over bleeder nipple
  • Catch bottle and disposable container for old fluid
  • Brake bleeder kit or vacuum pump (optional one-person method)
  • Clean rags, shop towels, safety glasses, gloves
  • Jack or blocks to safely support ATV if wheel removal is needed
  • Small funnel (clean) for reservoir

Preparation & Safety

  • Work on a flat, stable surface. Park ATV in gear and set parking brake (or chock wheels).
  • Clean around master cylinder cap to prevent dirt entering reservoir.
  • Protect painted surfaces & plastic with rags; brake fluid damages paint and plastic.
  • Wear safety glasses & gloves. Dispose of old fluid properlydo not pour down drains.

Step-by-Step: Replace Fluid & Bleed Brakes

1. Inspect and identify systems

Confirm which brakes are hydraulic. If the rear is cable/drum, you will not bleed it. Identify location of the master cylinder reservoir and bleeder nipples on calipers or wheel cylinders.

2. Remove old fluid from reservoir

  1. Open the master cylinder cap (remove reservoir cover or diaphragm). Use clean rags to wipe the rim.
  2. Siphon or turkey-baste old fluid from reservoir into a waste container until most old fluid is removed. Do not run reservoir dry in operation steps below.

3. Add fresh fluid

Pour fresh DOT 3/DOT 4 brake fluid into the reservoir to the recommended level. Replace small sections of fluid as you bleed to avoid drawing air.

4. Bleeding order

Always bleed starting with the brake furthest from the master cylinder and work toward the closest. On many ATVs that means: (1) right front, (2) left front (if applicable), then (3) rear (if the rear is hydraulic). If unsure, identify master cylinder outlet routing and choose the farthest wheel first.

5. Two-person bleed method (recommended if available)

  1. Person A sits on the machine and applies steady pressure to the brake lever or pedal and holds it.
  2. Person B places a clear hose over the bleeder nipple, routes the hose into a catch bottle partly filled with clean fluid to prevent air re-entry, and opens the bleeder nipple about 1/4 to 1/2 turn.
  3. Fluid & air will flow into the bottle. When flow slows, Person B closes the nipple. Person A then releases the lever/pedal slowly.
  4. Top up the master cylinder reservoir immediately after each cycle to prevent air suction.
  5. Repeat until no air bubbles appear and fluid exiting is clean. Move to the next wheel in the bleed sequence.

6. One-person vacuum or pressure method

  1. Attach a hand vacuum pump or a bench bleeder to the bleeder nipple or master cylinder per tool instructions.
  2. Operate the tool while keeping the reservoir topped. Open bleeder nipples and allow fluid and air to evacuate, closing nipples before releasing vacuum per your tool's direction.
  3. Repeat for each wheel until bubble-free fluid flows.

7. Final checks

  • Once bleeding is complete, tighten bleeder nipples to spec snugness (do not over-torque) and wipe all fittings clean.
  • Top reservoir to the correct level, replace cap and diaphragm, and secure cover.
  • Test brake lever/pedal for firm feel with ATV supported so wheels can turn freely. If lever/pedal is spongy, repeat bleeding.
  • Inspect for leaks around calipers, lines, master cylinder, and bleeder nipples.

Model-Specific Maintenance Tips for the TRX300 FOURTRAX 2x4

  • Front caliper bolts and bleeder nipples can corrode on older machines. Apply penetrating oil ahead of loosening and replace corroded nipples if they round off.
  • If your machine has the common front hydraulic caliper, use care removing caliper mounting bolts — note torque and keep pads in place to avoid overtravel of the piston. Compress piston gently with a pad-spreader or C-clamp only when installing new pads.
  • If the rear is mechanical (cable/drum), periodically lubricate the cable at pivot points and inspect the drum shoes for wear; no fluid bleeding is required for mechanical drums.
  • After a brake fluid change, monitor brake performance over the first few rides and recheck for leaks and fluid level. Older master cylinder seals can allow air to re-enter; replace seals or the master cylinder if bleeding repeatedly fails to firm the system.
  • Keep a spare small bottle of DOT-specified fluid in your garage for topping off after initial road testing.

Troubleshooting

  • Spongy lever/pedal after bleeding: re-bleed, check for leaks, inspect for collapsed hoses or master cylinder seal failure.
  • Brake drag after bleeding: ensure bleeder nipples are fully closed, caliper slides are clean and lubricated, and pistons return freely.
  • Persistent air: use a pressure or vacuum bleeder, or perform a reverse bleed (pressure from caliper to reservoir) only if familiar with risks and contamination prevention.

Disposal & Final Notes

Dispose of old brake fluid according to local regulations. Do not reuse fluid. Document the service date and fluid type used in your maintenance log. If you detect serious leaks, seized calipers, or master cylinder failure, replace components with quality parts appropriate to the 1997 TRX300 FOURTRAX 2x4.

If you need replacement parts or service components specifically for your 1997 TRX300 FOURTRAX 2x4, use the MotoSport parts page above to find compatible brake hoses, lines, caliper hardware, bleeder screws, and fluid.

Related Shopping Categories

Shop Brake Fluid for a 1997 Honda TRX300FOUR ATV.

Shop Brake Bleeders for a 1997 Honda TRX300FOUR ATV.

Shop Brake Pads for a 1997 Honda TRX300FOUR ATV.

Shop Brake Lines for a 1997 Honda TRX300FOUR ATV.

Shop Brake Tools for a 1997 Honda TRX300FOUR 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.