How to Bleed and Replace Brake Fluid on a 2012 Suzuki King Quad 400ASi 4X4 AUTO

Shop parts for a 2012 Suzuki King Quad 400ASi 4X4 AUTO ATV.

This MotoSport-exclusive procedure walks you through safely draining, flushing, and bleeding the brake hydraulic system on a 2012 Suzuki King Quad 400ASi 4X4 AUTO. Follow every step carefully. If you are not comfortable with brake work, have a qualified mechanic perform the job.

What you'll need

  • High-quality brake fluid that meets FMVSS 116 specifications (DOT 3 or DOT 4). Check your owner’s manual for the factory recommendation.
  • Clear vinyl tubing to fit bleed nipples
  • Catch container for old fluid
  • Turkey baster or fluid syringe
  • Socket set and wrenches to access reservoirs and bleed nipples
  • Clean lint-free rags and brake cleaner
  • Latex or nitrile gloves and safety glasses
  • Jack and stands or ramps and wheel chocks (if wheel removal is required)
  • Assistant for manual bleeding (optional if using vacuum or pressure bleeder)

Model notes & safety considerations for the 2012 King Quad 400ASi

  • The 2012 King Quad 400ASi is a utility ATV with a hydraulic braking system designed for rugged use. There is no factory ABS on this model, so proper bleeding is critical for predictable pedal/lever feel.
  • Brake fluid reservoir(s) may be located under the seat or near the handlebars; consult the owner’s manual or remove the seat/cover panels to expose the reservoir(s). Keep the reservoir cap closed except while adding fluid to limit moisture absorption.
  • This model uses a split hydraulic circuit; bleeding all circuits is required to restore full system performance. Always maintain reservoir level during the procedure to avoid introducing air.
  • If pads or calipers are old/corroded, replace or rebuild before bleeding; contaminated or collapsing hoses require replacement rather than bleeding.
  • Brake fluid is hygroscopic and corrosive to paint & plastics — avoid spills and clean any fluid immediately.

Preparation

  1. Park on a level surface. Engage park and/or parking brake, turn off engine, remove key. Block wheels to prevent rolling.
  2. Clean around the reservoir cap to prevent contamination. Remove the cap and the fluid level membrane/diaphragm if present. Wipe inside the cap and surrounding area with a clean rag.
  3. Use a turkey baster or syringe to remove as much old fluid from the reservoir as possible. Dispose of used fluid properly.
  4. Refill reservoir with fresh brake fluid to the MAX line. Keep the reservoir topped during the entire procedure.
  5. If you plan to remove wheels to access calipers, lift the ATV on appropriate stands and remove wheels now. Support the vehicle safely.

Bleeding order

To avoid drawing air into other circuits, bleed from the caliper farthest from the master cylinder first, then proceed to the next-farthest. Typical sequence on many ATVs is: right rear, left rear, right front, left front. Confirm circuit layout visually before starting and adjust sequence as needed.

Manual (two-person) bleeding method

  1. Fit clear tubing over the caliper bleed nipple and submerge the other end in a small clear container partially filled with fresh brake fluid to prevent air re-entry.
  2. Have your assistant firmly press and hold the brake lever or pedal.
  3. Open the bleed nipple about 1/4 to 1/2 turn with the proper wrench. Fluid and air bubbles will travel into the tubing. Close the nipple before your assistant releases the lever/pedal.
  4. Top off the reservoir immediately to avoid running dry. Repeat pumping and opening until no air bubbles appear in the tubing and the lever/pedal feels firm.
  5. Move to the next caliper in the bleeding order; always top off the reservoir between calipers.
  6. After all calipers are done, cycle the brake lever/pedal several times to confirm firm feel. Double-check reservoir level and cap it securely.

One-person vacuum or pressure bleeding

  • Vacuum bleeder: Attach vacuum unit to bleed nipple and draw until clean fluid with no bubbles appears. Keep reservoir topped. Work through the calipers in the proper order.
  • Pressure bleeder: Follow the manufacturer directions. Pressurize the master cylinder reservoir per tool instructions and open each bleed nipple until clear, bubble-free fluid flows. This is the fastest and cleanest method for solo work.

Complete system flush (recommended)

  1. After bleeding each wheel, drain the reservoir and refill again, repeating the bleed sequence a second time. This ensures fresh fluid throughout the system rather than partial mixing with old fluid.
  2. For heavily contaminated or dark fluid, perform two full flushes.

Final checks

  1. Inspect all bleed nipples for tightness and any leaks. Torque to factory specs if available, or snug securely without rounding the nipple. Wipe clean any spilled fluid.
  2. Reinstall any removed wheels and torque lug nuts to spec. Lower the ATV safely.
  3. Check brake lever/pedal feel at rest and during a low-speed test ride in a safe area. Expect a firm, progressive feel; if spongy, repeat bleeding.
  4. Check the reservoir after a short test ride and top off if necessary.
  5. Properly dispose of old brake fluid according to local regulations.

Troubleshooting

  • Persistent spongy brake feel: likely trapped air or a leaking/caliper piston/seal issue. Re-bleed, inspect hoses for internal collapse, and check caliper seals.
  • Brake drag after bleeding: caliper pistons may have been pushed too far or seized. Retract pistons to correct clearance and inspect for sticking.
  • If the master cylinder reservoir empties quickly during bleeding, inspect for leaks in lines, calipers, or at hose connections.

Parts & wear items to inspect on the 2012 King Quad 400ASi

  • Brake pads and rotors – replace if worn, glazed, or scored.
  • Brake hoses – replace any that are cracked, swollen, or soft under pressure.
  • Caliper slide pins – clean, inspect, and lubricate with high-temperature brake grease to prevent uneven pad wear.
  • Master cylinder seal & reservoir cap – replace if cracked or leaking.

Perform brake fluid replacement and bleeding at regular intervals for best performance & longevity. If you prefer OEM-fit replacement parts and quality brake components for your 2012 King Quad 400ASi, visit MotoSport to source the right parts tailored to this MMY.

Related Shopping Categories

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Shop Brake Tools for a 2012 Suzuki King Quad 400ASi 4X4 AUTO 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.