How to Bleed & Replace Brake Fluid on a 2017 Honda Rancher 420 4X4 (FM1)

Shop parts for a 2017 Honda TRX420R4X4 ATV.

This MotoSport.com guide walks you step-by-step through safely flushing and bleeding the brake system on your 2017 Honda Rancher 420 4X4 (FM1). Follow these factory-minded procedures and MotoSport tips to maintain predictable braking performance, prevent contamination, and extend system life.

What you need

  • Honda-approved DOT 3 brake fluid (clean, unopened bottle)
  • Clear plastic tubing that fits snugly over bleed nipple
  • Catch container for old fluid
  • Brake bleeder wrench or 8mm open wrench (verify size on your calipers)
  • Rubber gloves, shop rags, and safety glasses
  • Small funnel or syringe to refill master cylinder reservoir
  • Optional: hand vacuum bleeder or pressure bleeder for faster, cleaner job
  • Floor jack or ramps and wheel chocks to access calipers if needed

Model notes for the 2017 Rancher 420 4X4 (FM1)

  • The Rancher FM1 commonly uses DOT 3 brake fluid; always verify the cap or owner’s manual on your machine before starting. Mixing different fluid types is harmful.
  • Reservoirs are small & exposed to the elements — contamination with dirt or water is the most common cause of degraded brakes on this model.
  • This ATV’s hydraulic plumbing runs to two front calipers and one rear caliper. Bleeding order should be from the caliper farthest from the master cylinder to the nearest to avoid air entrapment.
  • Inspect brake lines and banjo fittings for cracks or leaks while you’re working. Rubber lines on older machines can swell or crack and should be replaced if any doubt exists.
  • If your Rancher has been used in deep water or has spongy brakes after riding, a full fluid replacement and careful bleed is mandatory to restore performance.

Preparation

  • Park on level ground, engage park brake, and remove key. Chock wheels.
  • Clean around each reservoir cap and caliper bleed nipple to prevent dirt falling into the system.
  • Remove cap and diaphragm from the master cylinder reservoir(s). Cover the opening with a clean rag to keep contaminants out while attaching a funnel or if using a bleeder.
  • Place your catch container and tubing so fluid runs into the container without kinking the hose.

Bleeding sequence & method

Bleed from the caliper farthest from the master cylinder to the closest. On most Rancher FM1 layouts this order is typically: rear caliper first, then the front calipers starting with the right/front passenger side if that is further from the master cylinder. If you’re unsure of plumbing routing, identify the master cylinder and work outward, finishing with the caliper closest to it.

Manual two-person bleed (recommended if no pressure bleeder)

  1. One person pumps the brake lever/pedal slowly several times and holds pressure. The other person cracks the bleed nipple with tubing attached until fluid runs clear with no bubbles, then retightens nipple. Repeat until no bubbles are seen.
  2. Keep the reservoir topped with fresh DOT 3 fluid between cycles to avoid drawing air into the master cylinder.
  3. Work each caliper in sequence until all lines run clear and bubble-free.
  4. After finishing, have the lever/pedal held for 10-20 seconds while all nipples are tightened to prevent suck-back air.

Single-person vacuum or pressure bleed

  1. Attach vacuum pump tubing to the bleed nipple, open nipple, and pump until clear, bubble-free fluid flows. Close nipple, move to next caliper, refill reservoir as needed.
  2. Pressure bleeders (if available) speed the job and reduce contamination risk — follow the tool manufacturer’s instructions and maintain reservoir fluid level while bleeding.

Flushing vs. topping up

For best results replace all fluid rather than topping off. To flush: remove old fluid from reservoir with a syringe and refill with fresh fluid; then bleed until the expelled fluid matches new fluid color and shows no bubbles. Repeat until reservoir draws mostly new fluid.

Final checks

  • Ensure bleed nipples are properly tightened and wipe any spilled brake fluid from painted surfaces immediately — brake fluid can damage plastics and paint.
  • Confirm pedal/lever feel is firm and consistent. If sponginess persists after multiple good bleeding cycles, inspect for leaks, master cylinder failure, or internal caliper issues.
  • Check brake light switch and parking brake function if applicable after reassembly.
  • Road-test the ATV at low speed in a safe area to confirm braking performance before returning to normal use.

MotoSport maintenance tips

  • Replace brake fluid every 1-2 years or sooner if you ride in wet conditions. Water contamination lowers boiling point and harms braking under heavy use.
  • Stock replacement rubber hoses and banjo bolts are inexpensive preventive items; replace any suspect components during fluid service.
  • Keep a small bottle of DOT 3 in your trail kit and inspect reservoirs routinely for level & contamination.

Following this MotoSport.com procedure will keep your 2017 Honda Rancher 420 4X4 brakes reliable and safe. If you encounter persistent issues or internal caliper/master cylinder problems, consult a certified technician or bring your machine to a qualified shop for diagnosis.

Related Shopping Categories

Shop Brake Fluid for a 2017 Honda TRX420R4X4 ATV.

Shop Brake Bleeders for a 2017 Honda TRX420R4X4 ATV.

Shop Brake Pads for a 2017 Honda TRX420R4X4 ATV.

Shop Brake Lines for a 2017 Honda TRX420R4X4 ATV.

Shop Brake Tools for a 2017 Honda TRX420R4X4 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.