How to Bleed & Replace Brake Fluid on a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6)

Shop parts for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) ATV.

This MotoSport proprietary guide walks you through draining, flushing, and bleeding the hydraulic brake system on the 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6). Follow these steps precisely, use proper safety gear, and reference your owner's manual for any model-specific torque or maintenance intervals.

What you need

  • Honda-approved brake fluid (DOT 3 or DOT 4 as specified in your owner's manual); do not mix with mineral oil
  • Clear flexible hose and clean catch bottle
  • Brake bleeding kit, vacuum pump, or helper for manual pumping
  • Clean rags, disposable gloves, eye protection
  • Combination wrenches and appropriate-sized wrench for bleed nipples
  • Turkey baster or syringe for fluid removal; funnel and clean container for new fluid
  • Jack or ramps and sturdy stands to access wheels (if wheel removal required)

Model notes — what Rubicon owners should know

  • The TRX500 Rubicon DCT EPS has a compact master cylinder and reservoir mounted on the front close to the handlebars; reservoir capacity is small so monitor level continuously when flushing.
  • DCT (Dual Clutch Transmission) and the EPS wiring are near service areas; avoid spilling brake fluid on electrical connectors or painted surfaces — brake fluid is corrosive to paint and some plastics.
  • Caliper bleed nipples are exposed but can be easily rounded if overtightened. Use the correct wrench, and back off carefully if seized.
  • If your unit has aftermarket racks or accessories bolted near brake lines, inspect hose routing and clamps after reassembly to prevent chafing when steering or suspension moves.

Preparation

  • Park on level ground, engage park/neutral and set the parking brake. Remove key and disconnect battery negative if you will be working around electrical areas.
  • Clean the reservoir cap area to prevent contamination. Remove cap and diaphragm cover gently.
  • Top the reservoir to the MAX line with fresh brake fluid so air does not enter during the first steps.
  • Identify bleed sequence: work from the caliper farthest from the master cylinder to the closest. For Rubicon FA6 that typically means: right rear, left rear, right front, left front. Confirm by visually tracing lines from the master cylinder.

Step A – Drain & Replace Reservoir Fluid (initial flush)

  1. Use a turkey baster or syringe to remove as much old fluid from the reservoir as possible. Dispose of old fluid per local regulations.
  2. Refill to the MAX line with new fluid. This prevents sucking in air when you start bleeding.

Step B – Bleeding methods (choose one)

Vacuum or pressure bleeder (recommended)

  1. Attach clear hose to the caliper bleed nipple and route to a catch bottle partially filled with fresh fluid to prevent air re-entry.
  2. If using a vacuum pump, attach to the bleed nipple, open the nipple, and draw until fluid runs clear without air bubbles. Close nipple while under vacuum, then release and repeat at the next caliper.
  3. Maintain reservoir level; never let it drop below the MIN line.

Two-person pump-–hold method

  1. Have an assistant sit on the ATV and slowly pump the brake lever (or pedal) several times, then hold firm.
  2. Open the bleed nipple about 1/4 turn to let fluid and air escape into the hose. Close nipple before the assistant releases pressure.
  3. Repeat until no air bubbles are visible. Keep reservoir topped off between cycles.

Gravity bleed (slowest)

  1. Open bleed nipple slightly and let fluid flow down into a catch bottle under gravity. This can take a long time but avoids pump-induced air ingestion.
  2. Carefully monitor reservoir level to avoid introducing air.

Step C – Bleed sequence

  1. Start with the caliper farthest from the master cylinder (commonly right rear), then move to the next farthest: left rear, right front, left front.
  2. At each caliper: attach hose, have a helper pump & hold or use vacuum, open nipple, purge air & old fluid until clear and bubble-free, then close nipple before releasing pressure.
  3. Always tighten bleed nipple snugly after finishing each caliper to prevent leaks. Wipe away any spilled fluid immediately.

Step D – Final reservoir top-off & system check

  • Top reservoir to MAX, reinstall diaphragm and cap. Clean any spilled fluid from painted or plastic surfaces and rinse with water if contact occurred.
  • Cycle the brake lever or pedal several times; it should feel firm and consistent. If soft or spongy, repeat bleeding at the calipers showing problems.
  • Inspect lines, hoses, and fittings for leaks while an assistant applies steady brake pressure.

Post-service checks & maintenance tips

  • Dispose of used brake fluid responsibly. Do not reuse or pour down drains.
  • Replace reservoir diaphragm if cracked or hardened; replace bleed nipple hardware if rounded or leaking.
  • Check brake pads and discs for wear while you have wheels off. Replace pads before rotor damage occurs.
  • Bleed every 1-2 years or sooner if brakes feel soft. Frequent heavy use or water exposure shortens fluid life.
  • If you encounter persistent sponginess after repeated bleeding, inspect master cylinder seals and internal caliper seals for failure and replace as needed.

Troubleshooting

  • Persistent air: ensure reservoir never dropped below MIN during bleeding; repeat full system bleed starting at the farthest caliper.
  • Leaking nipple: replace and retighten; use fresh copper crush washer if equipped or specified by Honda.
  • Brake drag after bleeding: check caliper sliding pins, pad fitment, and routing of hoses for kinks.

Perform this service in a clean, well-lit area and take your time. If any component appears damaged or you are uncomfortable with the procedure, have a qualified technician at MotoSport or an authorized service shop complete the work for you.

Related Shopping Categories

Shop Brake Fluid for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) ATV.

Shop Brake Bleeders for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) ATV.

Shop Brake Pads for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) ATV.

Shop Brake Lines for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) ATV.

Shop Brake Tools for a 2018 Honda TRX500 Rubicon 4X4 DCT EPS (FA6) 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.