How to Bleed and Replace Brake Fluid on a 2011 Yamaha Grizzly 450 4X4

Shop parts for a 2011 YAMAHA GRIZZLY450 ATV.

This MotoSport-exclusive guide walks you through a safe, complete brake fluid flush and bleed on a 2011 Yamaha Grizzly 450 4x4. Procedures here are written for owners who want a reliable, repeatable result using common tools and a basic brake-bleeding kit.

What you need

  • DOT 4 brake fluid (Yamaha recommends DOT 3/4 compatible fluid; use fresh DOT 4 for best performance)
  • Clear tubing that fits bleed nipples
  • Brake-bleeder bottle or catch container
  • 7mm or appropriate open wrench for bleed nipples
  • Turkey-baster, syringe, or fluid-transfer pump
  • Clean rags, gloves, safety glasses
  • Jack or ramps and stands to secure ATV (wheel removal may be needed)
  • Optional: vacuum bleeder or pressure bleeder for one-person operation

Model notes for the 2011 Grizzly 450

  • The 2011 Grizzly 450 uses separate front and rear hydraulic brake systems: a hand lever for front brakes and a foot pedal with its own master cylinder for the rear. Bleed each system separately.
  • No factory ABS on this model year; bleeding is conventional hydraulic only.
  • Reservoir locations: front master cylinder – handlebar area; rear master cylinder – near the engine/frame on the right side under panels. Clean the cap area before opening to avoid contamination.
  • Brake hoses and bleed nipples are exposed when wheels/panels are removed; inspect hose condition and caliper mounting hardware while you work.

Preparation

  1. Park the ATV on level ground, set park brake, disconnect battery for safety if you will be working near electricals.
  2. Remove plastic panels if needed to access the rear master cylinder and calipers. Clean around reservoir caps thoroughly.
  3. Elevate wheels or place the ATV on stands so wheels rotate freely if you plan to bleed with calipers installed.
  4. Wear gloves & eye protection. Brake fluid damages paint & plastics – cover bodywork with rags where needed.

Step-by-step bleed & fluid replacement

Bleed the system furthest from each master cylinder first. For Grizzly 450 that typically means:

  • Rear caliper(s) first for the rear master cylinder
  • Front calipers next for the front master cylinder

1. Check & top off reservoir

  1. Open the reservoir cap and diaphragm. Remove old fluid level down to a safe minimum using a syringe or turkey-baster. Do not let the reservoir run dry during bleeding.
  2. Refill with fresh DOT 4 fluid to the "MAX/UPPER" mark.

2. Rear system (foot pedal master)

  1. Attach clear tubing to the rear caliper bleed nipple and route into a catch bottle partially filled with fresh fluid to prevent air ingestion.
  2. With an assistant: have them slowly depress and hold the foot brake pedal. Open the bleed nipple with the wrench about 1/4 turn until fluid/air flows into the tubing. Close the nipple, then have assistant release the pedal. Repeat until fluid runs clear with no air bubbles and reservoir level remains near full.
  3. If using a vacuum bleeder: attach to bleed nipple, open nipple, pump until clear fluid flows, then close nipple before stopping vacuum.
  4. Top the reservoir as needed; never let it go below the minimum while bleeding.
  5. Tighten the bleed nipple to a snug fit; wipe away any spilled fluid. Repeat for the other rear caliper if applicable.

3. Front system (hand lever master)

  1. Refill the front reservoir with fresh fluid to proper level.
  2. Attach tubing to the front caliper bleed nipple(s) and follow the same pump-and-hold method with an assistant using the hand lever: squeeze & hold, open nipple, close nipple, release lever, repeat until clear fluid/no air.
  3. If both front calipers are present, bleed the caliper furthest from the front master cylinder first, then the closer caliper.

4. Final checks and cleanup

  1. Ensure all bleed nipples are properly tightened. Refill reservoirs to the proper level and reinstall diaphragms & caps.
  2. Operate pedals and levers to verify firm feel before riding. If spongy, repeat bleeding until firm.
  3. Inspect for leaks around calipers, lines, and master cylinders. Torque any caliper or mounting bolts to factory specs if removed.
  4. Clean any fluid on painted surfaces immediately with water then polish; replace damaged paint as needed.
  5. Dispose of old brake fluid per local hazardous-waste regulations.

Tips & troubleshooting

  • If the lever or pedal feels spongy after bleeding, suspect air trapped in lines or a failing master cylinder. Repeat bleeding and bench-test the master if necessary.
  • Use a pressure or vacuum bleeder to make one-person bleeding easier and reduce the chance of introducing air.
  • Replace rubber seals or o-rings at the master cylinder if they appear cracked or soft. Old reservoirs diaphragms can deform & allow contamination – replace if degraded.
  • Inspect brake hoses for swelling, cracks, or soft spots. Replace hoses if any damage appears; they degrade with age and cause poor braking performance.
  • Always keep the reservoir capped between steps to minimize moisture contamination; DOT fluid absorbs water over time which reduces boiling point and brake performance.

Maintenance interval recommendation

MotoSport recommends flushing and replacing brake fluid every 1-2 years for ATV use, or sooner with heavy or wet use, to maintain braking performance and prevent internal corrosion.

Final note specific to the MMY Grizzly 450 owner

Your MMY Grizzly 450 benefits from scheduled brake-system checks because separate front & rear masters mean two places for moisture or contamination to cause problems. If you plan to use aftermarket parts, choose quality caliper rebuild kits, hoses, and DOT 4-compatible components. Keep a log of fluid changes and any parts replaced to preserve resale value and safety.

Related Shopping Categories

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Shop Brake Pads for a 2011 YAMAHA GRIZZLY450 ATV.

Shop Brake Lines for a 2011 YAMAHA GRIZZLY450 ATV.

Shop Brake Tools for a 2011 YAMAHA GRIZZLY450 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.