How to Bleed & Replace Brake Fluid on a 1999 Polaris XPLORER 400 4x4

Shop parts for a 1999 Polaris XPLORER 400 4x4 ATV.

This MotoSport guide walks you through a full brake fluid change and bleed on the 1999 Polaris Xplorer 400 4x4. It's written for DIYers who want reliable, safe results and includes model-specific notes owners should know before starting.

What you'll need

  • DOT brake fluid as specified by Polaris for 1999 Xplorer 400 – confirm in your owner's manual
  • Brake-bleeder kit or clear vinyl tubing and a catch bottle
  • Box-end wrench to fit bleed nipples (typically 8mm-11mm)
  • Turkey baster or fluid syringe
  • Clean rags, gloves, eye protection
  • Brake cleaner and a small wire brush
  • Torque wrench for bleeder/banjo fittings if needed
  • Jack or stands to safely lift the ATV if wheel access is required

Safety & prep

  • Work in a well-ventilated area. Brake fluid damages paint & plastics — protect surfaces and rinse spills immediately.
  • Park the ATV on level ground, set the parking brake, and disconnect the battery if you'll be handling electrical components near the master cylinder or reservoirs.
  • Identify master cylinders: the Xplorer's front master cylinder is on the right handlebar; the rear master cylinder is typically near the footbrake linkage. Confirm visually before starting.
  • Inspect hoses, banjo fittings, caliper boots, and master-cylinder seals for leaks or deterioration. Replace damaged parts before bleeding.

Model notes for the 1999 Xplorer 400 4x4

  • 1999 Xplorer 400 uses a separate front (handlebar) master cylinder and a rear master cylinder actuated by the foot lever. Bleeding must address both systems independently.
  • The factory system commonly uses DOT-spec fluid; check your owner's manual sticker or factory tag to verify DOT 3 or DOT 4 for your specific unit before topping or flushing.
  • Some Xplorer 400s have short hose runs and compact reservoirs that can trap air — extra cycles may be needed for a firm pedal. If the pedal remains spongy after multiple bleeds, inspect for collapsed hoses, internal master-cylinder issues, or contaminated calipers.
  • Older units often have seized bleeder screws from corrosion. Apply penetrating oil and allow soaking time; if a screw rounds off, replace the caliper or have a shop extract the stud to avoid causing thread damage.

Step-by-step: replacing all brake fluid (complete flush) & bleeding

Follow this order: bleed the caliper(s) farthest from the master cylinder first, finishing with the closest. For the Xplorer 400's front system that usually means the passenger-side/front-right caliper first (if applicable), then the other front caliper, finishing at the front master cylinder. For the rear system, bleed the rear caliper(s) starting with the caliper farthest from the rear master cylinder.

  1. Remove old fluid from the master-cylinder reservoirs using a turkey baster or syringe until about 75% empty. Do not let the reservoir run dry during the process once bleeding begins.
  2. Top the reservoir with fresh DOT fluid to the recommended level.
  3. Attach clear tubing to the bleed nipple and place the other end into a bottle partially filled with fresh fluid to submerge the hose end. This prevents air being drawn back in.
  4. One wheel/caliper at a time: loosen the bleeder screw about a quarter turn. Have an assistant firmly press the brake lever/pedal several times, then hold it down. Open the bleeder screw to allow fluid and air to escape; close the screw before the assistant releases the lever/pedal. Repeat until clear, bubble-free fluid flows and the lever/pedal feels firm.
  5. Keep the master reservoir topped during the whole procedure. Never let it run dry or you will reintroduce air into the system.
  6. Work methodically through each caliper in the correct far-to-near sequence for each system. After bleeding all calipers, bleed the master-cylinder banjo fittings if applicable by briefly actuating the brake while a helper holds pressure and you crack then re-tighten fittings to purge trapped air (use care — only small turns).
  7. After bleeding, tighten bleeder nipples to spec or snug with the correct torque. Wipe all connections clean, replace reservoir caps, and properly dispose of old fluid per local regulations.
  8. Test brakes at low speed in a safe area. Repeat bleeding if pedal is still soft. If sponginess persists after repeated correct bleeding, inspect for internal master-cylinder issues, caliper piston seals, or collapsing hoses.

Tips for a clean, effective job

  • Always use fresh, unopened brake fluid. Never mix DOT types unless approved by Polaris documentation.
  • Replace bleeder screws or calipers showing corrosion or rounding; they're inexpensive compared with the risk of a partial bleed or leak.
  • If you don't have an assistant, use a one-person bleed bottle or vacuum bleeder. MotoSport stocks manual and vacuum bleeders compatible with ATVs.
  • After service, remove any fluid traces from painted surfaces with brake cleaner; brake fluid will etch paint quickly.
  • Record the service date and mileage/hours for future maintenance tracking.

When to seek professional help

  • Persistent soft pedal despite correct bleed technique
  • Seized or damaged bleeder screws that cannot be removed without risk
  • Major corrosion or leaking master cylinder, hoses, or calipers

Performing a thorough brake fluid change and bleed will restore the braking performance and safety of your 1999 Polaris Xplorer 400 4x4. If you need OEM- or performance-grade replacement parts, use the MotoSport parts link above to find properly matched components for your MMY.

Related Shopping Categories

Shop Brake Fluid for a 1999 Polaris XPLORER 400 4x4 ATV.

Shop Brake Bleeders for a 1999 Polaris XPLORER 400 4x4 ATV.

Shop Brake Pads for a 1999 Polaris XPLORER 400 4x4 ATV.

Shop Brake Lines for a 1999 Polaris XPLORER 400 4x4 ATV.

Shop Brake Tools for a 1999 Polaris XPLORER 400 4x4 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.