How to Bleed and Replace Brake Fluid on a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5)

Shop parts for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) ATV.

Overview

This guide from MotoSport walks through draining, replacing, and bleeding the brake fluid on a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5). It covers tools, safety, model-specific notes, and multiple bleeding methods so you can complete the job cleanly and reliably.

What you need

  • Honda-recommended brake fluid (use DOT 4 only) – fresh, unopened bottle
  • Clear vinyl tubing & collection bottle
  • Wrench set (8mm, 10mm or sizes to fit bleeder & banjo bolts)
  • Vacuum bleeder or hand pump (optional, speeds the process)
  • Turkey baster or fluid siphon
  • Clean lint-free rags & brake parts cleaner
  • New banjo crush washers (replace whenever you open banjo fittings)
  • Torque wrench for reassembly
  • Workstand, jack, wheel chocks
  • Safety glasses, nitrile gloves

Model-specific notes for the TRX500 Rubicon 4X4 DCT (FA5)

  • The TRX500 Rubicon DCT has separate master cylinders for front and rear brakes: the front master is mounted at the handlebar and the rear master is at the brake pedal. Bleed each system separately.
  • This model does not use a combined ABS system, but check for any accessory ABS-like modules before assuming a simple hydraulic loop.
  • When working on the DCT variant, ensure the transmission is in Park and the parking brake is engaged; the DCT electronics can change load if the unit is not secured.
  • Replace banjo bolt crush washers on caliper connections whenever they are loosened to avoid leaks.
  • Keep brake fluid off painted plastic and metal: it damages finish. Wipe spills immediately.

Safety & preparation

  • Work on a level surface, engage park, and chock wheels.
  • Wear eye protection & gloves. Brake fluid is corrosive to paint and skin.
  • Never reuse opened brake fluid once contaminated. Dispose of old fluid according to local hazardous-waste rules.
  • Do not mix DOT levels. Use DOT 4 only for this model.

Step 1 – Inspect and prepare

  • Clean the master cylinder reservoir caps and surrounding area.
  • Remove the rubber cap and diaphragm from the reservoir; keep debris out.
  • Check current fluid color – dark or dirty fluid indicates full replacement is needed.
  • Top reservoir to the MAX mark with fresh DOT 4; do not overfill.

Step 2 – Decide bleeding method

Choose one: two-person pump-and-hold, vacuum/pressure bleeder (recommended for one person), or gravity bleed (slow, low-effort). Vacuum or pressure bleeders give the cleanest, fastest results.

Step 3 – Bleeding sequence

Always bleed the circuit farthest from the master cylinder first and finish closest. Because the TRX500 has separate front and rear master cylinders, treat each as its own system:

  • Front brake system (handlebar master): if dual calipers, bleed the caliper farthest from the master first (typically right then left, but verify by tracing lines).
  • Rear brake system (pedal master): bleed the rear caliper(s) following the same farthest-to-closest logic.

Step 4 – Two-person pump-and-hold method

  1. Person A pumps the brake lever/pedal several times then holds it under light pressure.
  2. Person B opens the bleeder screw about 1/4 turn, letting fluid & air escape into clear tubing into a bottle. Close screw before Person A releases pressure.
  3. Repeat until clear fluid free of bubbles flows. Keep reservoir filled between cycles to avoid drawing air back in.
  4. Work quickly &mdash avoid letting the reservoir drop below the minimum mark.

Step 5 – Vacuum/pressure bleeder method (recommended)

  1. Attach vacuum hose to the bleeder nipple with clear tubing; place other end in a catch bottle.
  2. Apply constant vacuum, then open the bleeder screw. Maintain a full reservoir and periodically top with fresh fluid.
  3. Continue until fluid runs clear with no bubbles, then close bleeder while vacuum is still applied to avoid sucking air back in.

Step 6 – Gravity bleed (if you have no tools)

  1. Attach clear tubing to the bleeder and let fluid drip slowly while topping reservoir frequently.
  2. This will take longer and can be less effective at removing trapped air; use as last resort.

Step 7 – Final steps for each circuit

  • Once clear, torque bleeder screws and any banjo bolts to manufacturer specs. Replace crush washers if removed.
  • Wipe any spilled fluid clean with a rag and brake cleaner.
  • Refill reservoir to the MAX mark and install diaphragm & cap.
  • Check lever and pedal feel &ndash they should be firm. If spongy, repeat bleeding until firm.
  • Test brakes at low speed in a safe area before riding normally.

Torque & hardware notes

  • Always use new crush washers for banjo bolts. Reusing crushed washers risks leaks.
  • Tighten banjo bolts and bleeder screws to the proper torque; if unsure, snug components and check for leaks, then consult your shop manual for exact values.

Troubleshooting

  • Persistent sponginess: check for air in the lines, leaking fittings, or a failed master cylinder.
  • Brake drag after bleeding: ensure calipers and pistons move freely and that pads are seated correctly.
  • Slow lever/pedal return: inspect return springs and master cylinder pushrod adjustment.

Maintenance schedule recommendation

Replace brake fluid every 2 years or sooner if the fluid darkens. Riding in wet or muddy environments accelerates contamination; inspect fluid more often under those conditions.

Waste disposal

Never pour brake fluid down drains or onto ground. Store used fluid in a sealed container and dispose of it at a hazardous-waste facility or automotive recycling center.

Final checks before riding

  • Confirm no leaks at any fittings and that reservoirs are sealed.
  • Verify lever/pedal firmness and brake performance at low speed.
  • Recheck torque on banjo bolts after a short test ride.

For model-specific replacement parts, brake lines, or master cylinder components unique to the 2018 TRX500 Rubicon DCT, visit the MotoSport parts page above to find items matched to your MMY.

Related Shopping Categories

Shop Brake Fluid for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) ATV.

Shop Brake Bleeders for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) ATV.

Shop Brake Pads for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) ATV.

Shop Brake Lines for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) ATV.

Shop Brake Tools for a 2018 Honda TRX500 Rubicon 4X4 DCT (FA5) 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.