How to Bleed and Replace Brake Fluid on a 2015 Honda Rancher 420 4X4 DCT IRS (FA5)

Shop parts for a 2015 Honda TRX420DCI ATV.

This MotoSport guide walks you through safely flushing and bleeding the brake system on a 2015 Honda Rancher 420 4X4 DCT IRS (FA5). Follow each step carefully, use the correct tools and fluid, and consult your owner’s manual for specifications. This procedure is written for the ATV owner doing routine maintenance or preparing the machine for heavy use.

Notes specific to the 2015 Rancher 420 FA5

  • The Rancher 420 FA5 uses hydraulic front brakes and a sealed rear brake/parking assembly integrated with the drivetrain; bleeding focuses on the hydraulic calipers and master cylinder reservoir servicing.
  • The FA5 trim has a DCT automatic transmission and IRS rear suspension. Avoid contaminating transmission or differential components when working near the brake lines or when draining fluid.
  • Honda recommends checking the owner’s manual for the exact DOT specification for brake fluid. Use fresh, unopened DOT fluid only and never mix brake fluid types.
  • Inspect flexible brake hoses and line fittings for age cracking or leaks while you work; replace any suspect part before finishing the bleed.

Tools & materials

  • Fresh DOT brake fluid (check owner’s manual for DOT 3 or higher recommendation)
  • Brake-bleeding wrench set or line wrench
  • Clear plastic tubing and a catch bottle
  • Vacuum bleeder, pressure bleeder, or helper for manual pump bleeding
  • Turkey baster or syringe for removing old fluid from the reservoir
  • Clean shop rags, gloves, eye protection
  • Jack and stands or ramps to safely lift wheels if required
  • Brake cleaner and a small brush for caliper cleaning

Safety first

  • Work on a cool bike on level ground with the engine off and parking brake released as required by the manual.
  • Brake fluid damages paint and plastic. Protect painted surfaces and wipe spills immediately.
  • Dispose of old brake fluid responsibly at an approved facility.

Prep steps

  1. Park the ATV on level ground and secure it so it won’t roll. Remove the key.
  2. Clean the master cylinder reservoir cap and surrounding area to keep contaminants out.
  3. Remove the reservoir cap and diaphragm. Using a turkey baster, remove most of the old fluid from the reservoir without introducing air into the system.
  4. Top the reservoir with fresh DOT-approved fluid to the recommended level. Keep the cap off but the reservoir covered with a clean rag to reduce contamination while working.
  5. Inspect hoses, fittings, calipers and pads for wear or damage. Replace as needed before bleeding.

Recommended bleed order

Bleed starting with the wheel farthest from the master cylinder and finish with the closest. For many Rancher configurations this sequence is:

  1. Right front caliper (if master cylinder is front-mounted)
  2. Left front caliper
  3. Rear caliper or rear brake line

If you are unsure of the master cylinder location, consult the manual; the key principle is farthest to nearest.

Bleeding methods

One-person vacuum or pressure bleeder (preferred)

  1. Attach vacuum or pressure bleeder to the master cylinder reservoir per tool instructions.
  2. Attach clear tubing to the bleed nipple on the farthest caliper; place the other end into a catch bottle partially filled with fresh fluid to prevent air ingestion.
  3. Open the bleed nipple with the correct wrench. Operate the vacuum/pressure tool so fluid flows steadily until clean, bubble-free fluid appears. Close the nipple while flow continues to prevent air re-entry.
  4. Top the reservoir with fresh fluid as needed to avoid drawing air into the master cylinder.
  5. Repeat this process for each wheel in the bleed order.

Two-person manual pump method

  1. Person A sits on the ATV and slowly pumps the brake lever or pedal 3–5 times, then holds steady pressure.
  2. Person B opens the bleed nipple and allows fluid and air to exit into the clear tubing and catch bottle until flow slows, then closes the nipple.
  3. Person A releases the lever/pedal slowly; do not let it snap back. Repeat pump/hold/open cycles until clean, bubble-free fluid appears.
  4. Keep reservoir topped off during the procedure to avoid introducing air.
  5. Proceed through each caliper in the bleed order.

Finishing steps and checks

  1. With all calipers bled, ensure the reservoir is at the proper level and reinstall the diaphragm and cap securely.
  2. Clean any spilled brake fluid from components and paint, and re-tighten bleed nipples to spec without over-torquing.
  3. Cycle the brake lever/pedal several times to confirm firm, consistent feel. If the lever is spongy, repeat bleeding focusing on removing trapped air.
  4. Lower the machine, test brakes at low speed in a safe area before returning to normal operation.
  5. Record the service date and fluid type/brand used for maintenance records.

Troubleshooting

  • Persistent spongy brakes: likely air still in the lines or a leak. Recheck hoses, fittings and master cylinder seals.
  • Brake lever bottoms out but no visible leaks: check caliper pistons and master cylinder for internal issues; rebuild or replace as needed.
  • Contaminated or dark fluid shortly after service: possible contamination during filling or a failing component that's shedding material; inspect and, if necessary, repeat a full flush.

MotoSport maintenance tips for FA5 owners

  • Use only fresh, high-quality DOT brake fluid from a sealed container — brake fluid absorbs moisture quickly once opened.
  • If you use aftermarket parts, choose components rated for ATV loads and the Rancher’s brake caliper specs. MotoSport stocks OEM and performance-compatible parts for this model.
  • When replacing brake hoses, use braided or OEM-spec hoses with proper fittings to avoid fitment issues near the IRS components.
  • After heavy trail use, check brakes more frequently — mud and water cross-service can accelerate contamination and pad wear.

Performing a full brake fluid change and bleed on your Rancher 420 FA5 keeps stopping power reliable and prolongs brake component life. If you need OEM or upgrade parts to complete the job, visit the MotoSport parts page linked above to find fitment-specific components and consumables.

Related Shopping Categories

Shop Brake Fluid for a 2015 Honda TRX420DCI ATV.

Shop Brake Bleeders for a 2015 Honda TRX420DCI ATV.

Shop Brake Pads for a 2015 Honda TRX420DCI ATV.

Shop Brake Lines for a 2015 Honda TRX420DCI ATV.

Shop Brake Tools for a 2015 Honda TRX420DCI 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.