How to Bleed and Replace Brake Fluid on a 2020 Yamaha Grizzly 90
Shop parts for a 2020 YAMAHA GRIZZLY90 ATV.This MotoSport guide walks you through a safe, complete brake fluid service for the 2020 Yamaha Grizzly 90. Follow these steps precisely. If you’re not comfortable with brake systems, have a qualified technician perform the work.
What you need
- Yamaha-approved brake fluid (confirm DOT rating in your owner’s manual; DOT 3 or DOT 4 are common)
- Clear plastic tubing that fits bleeder nipples
- Catch bottle (marked, sealed for disposal)
- Hand pump or syringe (brake vacuum pump or two-person bench method)
- Clean rags, shop towels, nitrile gloves
- Small wrench for bleeder nipple (usually 8mm or 10mm)
- Phillips/flat screwdriver to open reservoir, small wire brush to clean cap area
- Jack/stands or ramp to access wheels (use rated stands and chock the vehicle)
- Torque wrench (for caliper or bracket bolts if removed)
Safety and prep
- Work on a level surface, engine off, key removed.
- Wear eye protection and gloves. Brake fluid is corrosive to paint & plastics — keep it away from finishes.
- Remove any debris from around the brake fluid reservoir cap before opening to avoid contamination.
- Position catch bottle below bleeder. Do not let fresh fluid run back into reservoir from the caliper hoses.
Model notes for the 2020 Yamaha Grizzly 90
- The Grizzly 90 uses a simple hydraulic braking system sized for a youth ATV. Reservoir capacity is small — don’t let it run dry during the procedure.
- Bleeder nipples are accessible but may be small and tight from factory assembly. Use a snug-fitting wrench to avoid rounding.
- Some Grizzly 90 units have combined front or rear master cylinder locations that make sequential bleeding straightforward — start closest to the master cylinder and work outward if in doubt.
- Replace rubber hoses if they show signs of cracking or swelling; small systems are more sensitive to air and soft hoses than larger machines.
Step-by-step: Replace brake fluid and bleed
- Clean reservoir cap. Remove cap and diaphragm carefully. Note fluid level and color; dark or dirty fluid should be fully replaced.
- Top reservoir with fresh fluid to the specified level. Keep cap loosely in place to minimize contamination while allowing overflow of air.
- Start with the wheel farthest from the master cylinder (if uncertain, begin with either front wheel and follow the sequence recommended in your manual). Attach clear tubing over the bleeder nipple and the other end into the catch bottle partially filled with some old fluid to prevent air being drawn back in.
- Crack the bleeder nipple about 1/4 turn. Use a hand pump or have an assistant slowly squeeze the brake lever/pedal several times then hold pressure. Open the bleeder while pressure is held to allow fluid/air out. Close the bleeder before the lever is released. Repeat until no air bubbles appear in the clear tubing and the fluid runs clean.
- Monitor reservoir level and top with fresh fluid as needed to prevent it from falling below the minimum — letting it go dry will reintroduce air into the system and require restarting the process.
- Once the first caliper/wheel is clear, tighten the bleeder nipple to snug. Move to the next wheel and repeat the process.
- After all wheels are bled, fill the reservoir to the proper mark and reinstall cap and diaphragm. Pump the brake lever/pedal to confirm a firm feel. If it feels spongy, repeat bleeding sequence.
- Clean any spilled fluid immediately. Dispose of old fluid according to local regulations.
Two common bleeding methods
- Two-person method: One operator maintains steady lever pressure while the other opens/closes the bleeder. This is simple and effective for small systems like the Grizzly 90.
- Vacuum or pressure pump: Use a vacuum pump at the bleeder or a pressure bleeder on the reservoir for a one-person, cleaner operation. Follow the tool maker’s instructions and do not over-pressurize the small reservoir.
Final checks
- Verify lever/pedal firmness and travel. The feel should be consistent and firm under normal force.
- Inspect bleeder nipples and reservoir for leaks. Tighten to specified torque if available, but avoid over-torquing small fittings.
- Test brake operation at low speed in a safe area before normal riding.
- Record the service date and fluid type for future maintenance tracking.
Troubleshooting
- Persistent spongy lever after correct bleeding: check for contaminated or collapsing hoses, a leaking master cylinder, or an internal ABS/valve issue if equipped.
- Bleeder that won’t stop leaking: replace the bleeder screw or install a new copper crush washer if used.
Perform brake fluid replacement at recommended intervals or whenever you see discolored fluid. Proper fluid and careful bleeding keep the Grizzly 90 safe and responsive for younger riders.
Related Shopping Categories
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Shop Brake Tools for a 2020 YAMAHA GRIZZLY90 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.