How to Bleed & Replace Brake Fluid on a 2018 Suzuki King Quad 400ASi 4X4 AUTO

Shop parts for a 2018 SUZUKI KINGQD4ASI ATV.

This MotoSport-exclusive service guide walks you through a complete, safe brake fluid change and bleeding procedure for the 2018 Suzuki King Quad 400ASi 4X4 AUTO. Follow all steps carefully, use the correct fluid, and inspect components for wear while you have the system open.

Important model notes for the 2018 King Quad 400ASi 4X4 AUTO

  • The 2018 King Quad 400ASi is a hydraulically braked ATV without factory ABS on most trims. That means traditional bleeding applies; no ABS pump cycling procedures are required.
  • Brake reservoirs are sealed plastic reservoirs and are reasonably compact. Check reservoir locations before starting so you can keep fluid levels stable while bleeding.
  • Suzuki recommends a DOT-specified hydraulic brake fluid — consult your owner’s manual for the exact spec; DOT 3 and DOT 4 are commonly acceptable, but never mix DOT 5 (silicone) with glycol-based fluids.
  • This model spends time in wet, dirty environments. Inspect calipers, hoses, fittings, and banjo bolts for corrosion, cracking, or seizing while replacing fluid.
  • If you ride in sand, water, or salt conditions frequently, plan to replace brake fluid more often (every 1-2 years) to avoid moisture contamination and internal corrosion.

What you’ll need

  • Correct DOT brake fluid as specified in your owner’s manual
  • Brake bleeder kit (vacuum pump, one-way syringe, or two-person hose and bottle)
  • Clear tubing to fit bleed nipples
  • Clean catch bottle, rags, gloves, and safety glasses
  • Wrenches to open bleed nipples (normally 8mm or 10mm depending on fitting)
  • Jack or ramps and stands to safely elevate the ATV if needed
  • Brake cleaner and a small brush for cleaning around fittings

Safety & prep

  • Work on a level surface with the engine off and ignition key removed.
  • Keep brake fluid off painted surfaces — it damages paint. Cover tank and bodywork with rags or plastic.
  • Open the brake fluid reservoir cap(s) and remove the diaphragm cover plate if equipped. Keep reservoir lids loosely off during bleeding to avoid vacuum build-up.
  • Use fresh, sealed brake fluid only. Don’t reuse old fluid and don’t bottle-dip from a partially used container exposed to moisture.

General bleeding strategy

Bleed the hydraulics from the wheel farthest from the master cylinder first and work toward the nearest wheel. If you do not know the exact plumbing for your model, use the following common ATV sequence: rear wheel (or rear caliper), then right front, then left front. If your King Quad has two independent reservoirs (front/rear), keep the reservoir for the system you’re bleeding topped up while working on that circuit.

Step-by-step bleed & fluid replacement

  1. Park, secure, and lift the ATV so wheels for the circuit you’re bleeding are free to rotate if needed.
  2. Clean around the reservoir caps and bleed nipples to avoid contamination.
  3. Suck or syringe out old fluid from the master cylinder reservoir until most contaminated fluid is removed, but do not completely empty the reservoir if system contains multiple circuits sharing a reservoir. Refill with fresh fluid to the correct level.
  4. Attach clear tubing to the bleed nipple of the farthest caliper and submerge the other end in a small catch bottle partially filled with fresh fluid (to avoid drawing air back in).
  5. Two-person pump method: Person A slowly depresses the brake lever or pedal to about 3/4 travel and holds. Person B opens the bleed nipple briefly to allow fluid to flow until the lever drops slightly, then closes the nipple before the lever is released. Repeat until clear fluid without air bubbles flows. Top up reservoir frequently.
  6. One-person vacuum or syringe method: Use a hand vacuum bleeder on the bleed nipple and open the nipple while drawing fluid. Keep reservoir topped up. Continue until clear fluid with no bubbles is drawn out.
  7. Repeat the bleed procedure for the next-farthest caliper, then the next, finishing with the caliper closest to the master cylinder. For a single-circuit brake system this sequence ensures trapped air is forced toward the master cylinder and bled out.
  8. Once all wheels are clear, tighten bleed nipples to correct snugness, wipe fittings, and top reservoir(s) to the specified level. Replace diaphragm and caps.
  9. Operate the brake lever or pedal slowly several times to confirm firm feel. Re-check nipples and reservoir for leaks.
  10. Lower the ATV and perform a low-speed test in a safe area to confirm braking performance before normal use.

Tips, diagnostics & troubleshooting

  • Spongy or sinking pedal after bleeding usually indicates remaining air in the system or a faulty master cylinder seal. Repeat bleeding or inspect the master cylinder for leaking seals.
  • If a caliper piston is hard to move, clean and free it before bleeding. A stuck piston can trap air or prevent full fluid flow.
  • If you find rusty or bulging brake hoses, corroded banjo bolts, or pitted caliper surfaces, replace those components rather than just replacing fluid.
  • Keep new fluid sealed and discard any fluid left in an open container after a service; brake fluid absorbs moisture from the air and degrades.
  • Record the service date and mileage; routine replacement every 12-24 months is a good preventive practice for machines exposed to moisture or heavy use.

When to seek professional help

  • You cannot achieve firm brakes after multiple bleeding attempts.
  • Evidence of major corrosion, damaged calipers, leaking master cylinder, or internal seal failure.
  • If you are unsure about reservoir plumbing or circuit layout on your specific King Quad model.

Following these steps will restore a firm, reliable brake feel on your 2018 Suzuki King Quad 400ASi 4X4 AUTO. Inspect hardware while you’re working and replace suspect parts to keep the system safe and serviceable.

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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.