How to Bleed and Replace Brake Fluid on a 2018 Honda Rancher 420 4X4 DCT IRS (FA5)
Shop parts for a 2018 Honda Rancher 420 ATV.
This MotoSport guide walks you through a safe, complete brake fluid change and bleed for the 2018 Honda Rancher 420 4X4 DCT IRS (FA5). Follow these steps carefully, observe safety precautions, and use only quality parts and fluid. This procedure is written specifically for this MMY ATV and the linked MotoSport parts page above lists compatible replacement components and bleed fittings.
Notes specific to the 2018 Rancher 420 DCT IRS
- The Rancher 420 DCT IRS uses hydraulic brakes with a combined system architecture; one master reservoir services front and rear circuits via proportioning valves. Observe the vehicle owner’s manual for fluid designation; use the manufacturer-recommended DOT fluid type only.
- The DCT (Dual Clutch Transmission) and IRS (Independent Rear Suspension) do not change bleeding order, but take care around electronics and linkage when raising or tilting the ATV.
- Park the ATV on level ground with engine off, transmission in Park, and parking brake applied. Block wheels to prevent movement.
- Brake fluid is hygroscopic and corrosive to paint and plastics — protect painted surfaces and clean spills immediately with water.
Tools & consumables
- Manufacturer-specified DOT brake fluid (confirm DOT 3 or DOT 4 in owner’s manual)
- Clear plastic tubing small enough to fit over bleed nipples
- Catch bottle partially filled with old fluid to prevent air ingress
- 9mm or 8mm wrench (bleeder nut size varies by caliper)
- Turkey baster or syringe to remove reservoir fluid
- Brake cleaner, rags, gloves, eye protection
- Assistant to operate brake lever/pedal
- Floor jack or ramps and jack stands if necessary (support securely)
Preparation
- Remove seat and access panels to reach the master cylinder reservoir; keep dirt away from the cap and surrounding area.
- Clean the reservoir cap area thoroughly. Remove the cap and diaphragm; use a turkey baster or syringe to extract as much old fluid as possible without introducing dirt.
- Inspect hoses, lines, calipers, and fittings for leaks, corrosion, or damage. Replace any worn components before bleeding.
- Top reservoir with a small amount of fresh brake fluid to prevent foam and air entry during the process.
Bleeding order and rationale
Bleed starting with the wheel farthest from the master cylinder and progress to the closest. Typical sequence for Rancher 420 (confirm visually where master cylinder is mounted):
- Rear caliper furthest from master
- Rear caliper closest to master
- Front caliper furthest from master
- Front caliper closest to master
Note: If the Rancher uses a single front master and integrated rear circuit, follow this sequence to minimize trapped air. If you locate multiple reservoirs, bleed each circuit independently.
Step-by-step bleed and fluid replacement
- Fill reservoir with fresh fluid to the full mark. Keep cap off but covered with a clean cloth to monitor level while preventing contamination.
- Attach clear tubing to the bleed nipple on the first caliper and place the other end into the catch bottle partially filled with old fluid. Ensure a tight fit to prevent air entry.
- Have your assistant slowly apply steady pressure to the brake lever or pedal until you see fluid and air bubbles flow into the tubing. Hold pressure while you open the bleed nipple briefly to let fluid escape, then close it before the assistant releases the lever/pedal.
- Repeat pumping and opening until clear fluid with no bubbles exits. Keep reservoir level topped up during the entire process to avoid introducing air into the system.
- Work through the bleeding sequence for each caliper. After finishing each wheel, clean the bleed nipple, tighten to spec, and remove tubing.
- Once all wheels are bled, perform a final lever/pedal feel check. The lever should be firm with minimal travel. If spongy, repeat bleeding focusing on the circuit with symptoms.
- Clean any spilled fluid, re-install reservoir diaphragm and cap, and torque fittings to factory values where specified. Dispose of old fluid properly.
Bench bleeding or pressure bleeding options
If available, a pressure bleeder or vacuum bleeder speeds the job and reduces contamination risk. Use only equipment rated for automotive brake fluid. Follow manufacturer instructions and do not over-pressurize the system.
Post-bleed checks & break-in
- Check pedal/leverage feel at cold and after a short ride. Re-check reservoir level and top if needed.
- Inspect all fittings and lines for leaks after a test ride. Re-torque bleed screws if seepage appears.
- New fluid can change pedal feel slightly; perform a cautious ride to bed in the system and verify brake performance before heavy use.
Common issues and troubleshooting
- Persistent spongy pedal: likely air still trapped or contaminated master cylinder internal seals. Re-bleed entire system; if unresolved, inspect master cylinder for internal failure.
- Brake drag after bleeding: check caliper pistons for corrosion or collapse of dust boots. Clean and service calipers if necessary.
- Fluid contamination: if fluid looks dark or contains particles, flush fully and consider replacing flexible hoses if they are degrading internally.
Model-specific maintenance tips
- Because the Rancher 420 is often used in muddy or wet conditions, inspect and replace brake hoses and seals on a schedule shorter than road vehicles. Mud and water accelerate wear.
- IRS linkages and suspension travel can change brake line routing stresses – periodically inspect line clamps and routing to prevent chafing after suspension use or lift kits.
- If installing aftermarket wheels or accessories from MotoSport, confirm that brake clearance and caliper positioning remain correct before riding.
Perform routine brake inspections and fluid replacement at intervals recommended by Honda or sooner if you operate in harsh conditions. For parts, fittings, and compatible replacement fluids or caliper hardware, use the MotoSport parts page linked above to ensure correct fitment for your 2018 Honda Rancher 420 4X4 DCT IRS (FA5).
Related Shopping Categories
Shop Brake Fluid for a 2018 Honda Rancher 420 ATV.
Shop Brake Bleeders for a 2018 Honda Rancher 420 ATV.
Shop Brake Pads for a 2018 Honda Rancher 420 ATV.
Shop Brake Lines for a 2018 Honda Rancher 420 ATV.
Shop Brake Tools for a 2018 Honda Rancher 420 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.
