How to Bleed & Replace Brake Fluid on a 2018 Textron Alterra 150

Shop parts for a 2018 Textron Alterra 150 ATV.

This MotoSport-exclusive maintenance guide walks you through safely flushing the brake system and replacing brake fluid on a 2018 Textron Alterra 150. Follow every step carefully, use clean tools, and dispose of old fluid properly. This procedure is written for the stock hydraulic brake system used on the Alterra 150 and assumes basic mechanical skill. If you’re unsure, consult a qualified technician.

What you’ll need

  • Manufacturer-compatible brake fluid (DOT 3 or DOT 4 — use what's specified in your owner’s manual or on the reservoir cap)
  • Clear plastic tubing that fits snugly over the bleeder nipples
  • Brake bleeder wrench or small open-end wrench
  • Turkey baster or fluid syringe
  • Clean catch container and rags
  • Rubber gloves & safety glasses
  • Jack or ramps and stands to lift the ATV if needed
  • Assistant for manual bleeding OR a one-way vacuum bleeder or pressure bleeder

Model-specific notes for the Alterra 150

  • The Alterra 150 uses a compact single-circuit hydraulic brake arrangementinspect both calipers and lines visually for leaks or chafing before starting.
  • Brake reservoir is small; do not allow it to run dry during bleeding. Running dry introduces air and requires additional bleeding cycles.
  • Rubber brake lines on small ATVs can harden with age; if lines are cracked or bulging, replace them rather than just bleeding.
  • Bleeder nipple locations are on the caliper body; they are smalluse the correct wrench to avoid rounding the hex.
  • After bleeding, test brake lever/pedal travel with the engine off before riding. Brake feel should be firm with minimal travel.

Safety preparation

  • Work on a level surface, ignition off, parking brake applied (if fitted) and wheels chocked.
  • Protect painted surfaces from spilled fluid & clean spills immediately; brake fluid can damage plastics & paint.
  • Wear protective gloves & eyewear.

Step 1 – Inspect and prepare

  • Check master cylinder/reservoir cap for markings that specify DOT 3 or DOT 4. Use only the specified fluid.
  • Clean the reservoir cap area to keep contaminants out when opening.
  • Remove the cap and diaphragm; top reservoir to the FULL mark with fresh fluid. Do not overfill.
  • Inspect calipers, lines, hoses, fittings and bleeder screws for corrosion or damage.

Step 2 – Two common bleeding methods

Method A: Manual two-person bleed (recommended if you have an assistant)

  1. Start with the wheel/caliper farthest from the master cylinder. On most Alterra 150 setups, that is the rear wheel first then the front — confirm by tracing lines from the reservoir.
  2. Fit clear tubing over the caliper bleeder nipple and place the other end into a catch bottle partially filled with fresh fluid to avoid drawing air back in.
  3. Have your assistant pump the brake lever/pedal several times and hold firm.
  4. Open the bleeder screw about 1/4 turn. Fluid & air will flow into the tubing. Close the bleeder when flow slows; then have assistant release the lever. Repeat until you see clean fluid with no bubbles.
  5. Keep the reservoir topped up during the process to prevent introducing air into the master cylinder.
  6. Move to the next caliper and repeat until all corners are clear of bubbles.

Method B: One-person vacuum or pressure bleeder

  1. Attach vacuum pump or pressure bleeder to the bleeder nipple or reservoir per tool instructions.
  2. If using a vacuum on the caliper bleeder, open the bleeder and draw fluid until clear, then close the bleeder while maintaining vacuum. Repeat at each caliper starting farthest from the master cylinder.
  3. If using a pressure bleeder on the reservoir, pressurize the reservoir per tool directions and open bleeders one at a time until fluid runs clear and bubble-free.
  4. Always keep the reservoir topped up to avoid drawing air in.

Step 3 – Complete fluid replacement (flushing)

  • After initial bleeding, perform a full system flush by repeatedly drawing fresh fluid through the system until the fluid exiting each caliper matches the new fluid in color and clarity.
  • Replace the reservoir fluid at regular intervals per maintenance schedule or sooner if contaminated.

Step 4 – Final checks

  • Tighten bleeder nipples to spec (hand-tight plus a small snug — avoid over-torquing and rounding). If you have a torque spec in your service info, use it.
  • Top the reservoir to the FULL mark, reinstall diaphragm & cap, and wipe away spilled fluid.
  • Operate the brake lever/pedal repeatedly until it feels firm. If it feels spongy, re-bleed.
  • Check for leaks around calipers, lines, hose connections & master cylinder while applying steady brake pressure.
  • Test ride at low speed in a safe area to confirm braking performance.

Troubleshooting & maintenance tips

  • Persistent sponginess after several bleeds indicates a leak, collapsed hose, or a faulty master cylinder/caliper that may need replacement.
  • If rust, seized slide pins, or sticky caliper pistons are found, service or rebuild the caliper. Replacing only fluid won't fix mechanical issues.
  • Store brake fluid in a sealed container and discard any fluid that looks dark or contaminated. Brake fluid is hygroscopic — it absorbs moisture over time, reducing boiling point and performance.
  • Record the date and mileage when you replace fluid; small ATVs like the Alterra 150 benefit from more frequent checks if used in wet/muddy conditions.

Parts & supplies reminder

When replacing hoses, seals or bleeder screws, use OEM-quality parts matched to the 2018 Textron Alterra 150. For convenience, find model-specific parts and brake components through MotoSport’s parts catalog for the Textron Alterra 150.

Follow all safety practices. If in doubt, have a trained technician perform brake work.

Related Shopping Categories

Shop Brake Fluid for a 2018 Textron Alterra 150 ATV.

Shop Brake Bleeders for a 2018 Textron Alterra 150 ATV.

Shop Brake Pads for a 2018 Textron Alterra 150 ATV.

Shop Brake Lines for a 2018 Textron Alterra 150 ATV.

Shop Brake Tools for a 2018 Textron Alterra 150 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.