How to bleed and replace brake fluid on a 2019 Textron Alterra 90

Shop parts for a 2019 Textron Alterra 90 ATV.

This MotoSport-exclusive procedure walks you through safely draining, flushing, and refilling the brake fluid on a 2019 Textron Alterra 90 (ALT90). Follow each step carefully, use recommended fluids and tools, and stop if you encounter damage or leaking components that require replacement.

Notes specific to the 2019 Textron Alterra 90

  • The ALT90 uses a simple, compact brake system designed for youth riders; it typically features a small master cylinder and caliper/actuation components sized for the chassis. Inspect components for wear or contamination before bleeding.
  • Brake reservoirs on this model are small – work in short intervals to avoid running the system dry while opening lines.
  • OEM replacement parts and seals are small and sometimes fragile; use genuine or high-quality parts if disassembly reveals worn hardware.
  • Check the owner's manual for the recommended DOT fluid (DOT3 or DOT4 are commonly used). When in doubt, use DOT4 for improved boiling point and compatibility, but confirm compatibility with any rubber lines or seals you find on the vehicle.
  • If the brake lever/pedal feels spongy after bleeding, repeat the bleed sequence or inspect for internal leaks, air in hoses, or a failing master cylinder.

Tools & supplies

  • Correct DOT brake fluid (check manual; DOT4 recommended if compatible)
  • Clear plastic tubing to fit bleeder nipple
  • Clean catch bottle with some fresh brake fluid to submerge tubing end (prevents air ingress)
  • Wrenches for bleeder nipple (typically 8mm or 10mm) and master cylinder cap
  • Turkey baster or fluid syringe (optional) to remove old fluid from reservoir
  • Clean rags, isopropyl alcohol or brake cleaner, gloves, eye protection
  • Torque wrench for caliper/line hardware if removal is required

Preparation

  1. Park the ALT90 on level ground, engage park/parking brake if fitted, disconnect the spark plug for safety.
  2. Clean around the brake master cylinder reservoir cap and bleeder nipples to prevent contamination.
  3. Remove the reservoir cap and diaphragm. Use a turkey baster or syringe to remove as much old fluid as possible from the reservoir.
  4. Refill the reservoir with fresh brake fluid to the specified level; do not overfill.
  5. Have a helper available if you plan to use the manual pump-and-hold method.

Bleeding methods (choose one)

1) One-person vacuum or syringe method (recommended for a single operator)

  1. Attach the clear tubing to the bleeder nipple and submerge the other end in a catch bottle partially filled with fresh fluid.
  2. Connect a hand vacuum pump or use a large syringe inline to draw fluid from the bleeder. Crack the bleeder nipple a 1/4 to 1/2 turn.
  3. Slowly pull fluid until you see clear fluid with no air bubbles. Periodically top off the master reservoir to keep it from running dry.
  4. Close the bleeder while maintaining vacuum, then remove tubing and wipe the nipple. Repeat until fluid runs clear and bubble-free (typically 3-6 cycles).
  5. Tighten bleeder to spec, wipe away any spilled fluid, reinstall the diaphragm and cap, and test lever/pedal feel.

2) Two-person pump-and-hold method

  1. Attach tubing to the bleeder and submerge the other end in fluid in the catch bottle.
  2. Helper slowly pumps the brake lever/pedal 3-5 times and then holds pressure.
  3. While held, open the bleeder until fluid flows and air escapes. Close the bleeder before the helper releases the lever/pedal.
  4. Repeat the pump-and-hold cycles until clear, bubble-free fluid appears. Keep reservoir topped off during the process.

3) Pressure or gravity bleed (optional for shops)

Pressure bleeders attach to the reservoir and push fluid through the system; follow manufacturer instructions for safe use. Gravity bleeding is slower — open bleeder(s) and let fluid flow down into a container, ensuring reservoir never runs dry.

Sequence and best practices

  • Bleed from the wheel farthest from the master cylinder first, then move to nearer wheels. On a simple ALT90 this may mean rear then front, or passenger side then driver side on dual setups — verify plumbing visually if unsure.
  • Always keep the reservoir topped off to avoid introducing air.
  • Use short, controlled bursts of pressure. Never let the master cylinder run dry.
  • Dispose of old fluid properly. Brake fluid is hygroscopic and contaminated fluid must not be reused.
  • Clean any spilled fluid immediately; it damages paint and plastics. Use isopropyl alcohol for cleanup and a rag.

Reassembly, inspection & final checks

  1. Confirm all bleeder nipples and reservoir cap are tightened to proper snugness. Do not over-torque small nipples.
  2. Wipe components clean, reinstall reservoir diaphragm and cap, and clean up fluid spills.
  3. Reconnect the spark plug if previously disconnected.
  4. With the ATV on level ground, slowly apply the brake several times to confirm a firm lever/pedal feel. If spongy, repeat bleeding.
  5. Short test ride at low speed in a safe area to confirm braking performance. Re-check fluid level and inspect for leaks after the test ride.

Troubleshooting

  • Persistent sponginess: likely air still in system, leaking line, or failing master cylinder. Re-bleed and inspect hardware.
  • Brake drag after bleeding: check for overfilled reservoir, trapped fluid, or caliper sticking; clean and service caliper as needed.
  • Fluid contamination or dark fluid: replace and flush system completely; inspect rubber lines for deterioration.

MotoSport maintenance tips for ALT90 owners

  • Bleed brake fluid every 1-2 years or sooner if performance degrades or fluid appears dark/cloudy.
  • Inspect brake lines, fittings, and mounting hardware during every fluid service; small cracks or leaks on youth ATVs can escalate quickly.
  • Keep extra fluid, spare bleeder caps, and a small bleed kit in your toolbox when riding or working remotely.
  • When replacing caliper seals or hoses, use components rated for DOT fluid and compatible with the ALT90's fittings.

Following this MotoSport-exclusive guide will keep your 2019 Textron Alterra 90 braking system safe and reliable. If you encounter damaged components or uncertain symptoms, consult a qualified technician or bring your ATV to a service center.

Related Shopping Categories

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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.