How to Bleed and Replace Brake Fluid on a 1989 Yamaha Blaster

Shop parts for a 1989 Yamaha Blaster ATV.

This MotoSport-proprietary guide walks you through safely draining, replacing, and bleeding the hydraulic brakes on a 1989 Yamaha Blaster MMY. Follow each step carefully, use the right fluid, and respect safety precautions specific to older two-stroke ATVs.

What you need

  • Correct brake fluid (check the reservoir cap for DOT spec — most older Yamahas use DOT 3; if unsure, use the cap label as authority)
  • Clear vinyl tubing to fit bleeder nipple
  • Catch bottle for old fluid
  • Box-end wrench sized to the bleeder nipple
  • Turkey-baster, syringe, or vacuum bleeder (optional)
  • Rubber gloves, eye protection, shop rags
  • Brake-cleaner and a small brush
  • Jack or stands to stabilize the ATV if you need wheel/caliper access

Model notes for the 1989 Yamaha Blaster

  • The Blaster is a compact 2-stroke sport quad with exposed brake lines and bleeder nipples on each caliper. Caliper and master cylinder placements are compact, so small tools and patience are required to access bleeders.
  • Because it’s a two-stroke, keep brake fluid away from the exhaust, engine intake, and painted surfaces — fluid ruins paint and can contaminate two-stroke oil handling if spilled.
  • Reservoirs on older ATVs can be brittle. Open the cap carefully, and if the plastic looks degraded, replace the reservoir or cap assembly before bleeding.
  • Blaster brake systems engineered for DOT 3 may swell rubber parts with DOT 4 if seals are previously degraded. If you change fluid types, flush completely and inspect hoses & seals for deterioration.

Safety first

  • Work on a cool vehicle and do not allow brake fluid to contact skin or painted surfaces. Clean spills immediately with water.
  • Never reuse old brake fluid. It absorbs moisture and degrades braking performance.
  • Keep the reservoir capped whenever possible to prevent moisture ingress and dirt contamination.

Step 1 – Prepping the bike

  • Place the Blaster on a level surface. Stabilize with a center stand or jack stands so it will not move while bleeding.
  • Clean the reservoir area and calipers with brake-cleaner. Remove dirt to avoid contamination.
  • Open the reservoir cap and remove the diaphragm; if the old fluid is dark or full of particles, plan to siphon most out before refilling.

Step 2 – Remove old fluid from reservoir

  • Use a turkey-baster or syringe to remove as much old fluid from the master cylinder reservoir as possible without lowering the level below the minimum mark. This reduces contamination when you top up with fresh fluid.
  • Wipe the inside of the cap and diaphragm if they are reusable — replace if degraded.

Step 3 – Decide your bleeding method

  • Gravity bleed — easy but slow: open bleeders and let fluid drip until clear. Keep reservoir topped.
  • Manual pump — a helper pumps lever/pedal while you open/close bleeder for short bursts.
  • Vacuum or pressure bleeder — fastest and cleanest; especially good for older systems with stubborn air.

Step 4 – Bleed sequence

General rule — start with the caliper farthest from the master cylinder and work toward the nearest. For the Blaster this usually means:

  • Rear caliper first (if the rear is farthest), then front caliper(s). If the system has a single front caliper, finish there.

Step 5 – Bleeding procedure (manual pump method)

  1. Attach clear tubing to the bleeder nipple and submerge the other end in a small amount of fresh fluid in a catch bottle so air cannot be sucked back in.
  2. Top the reservoir with fresh brake fluid to the fill line.
  3. Have a helper slowly pump the brake lever/pedal several times, then hold pressure (do not lock the lever tight, just steady pressure).
  4. With the lever held, open the bleeder nipple about a quarter to half turn. Fluid and air will flow into the tubing. Close the nipple before the helper releases the lever. Repeat until no bubbles appear and clear fluid flows.
  5. Keep checking and topping the reservoir between cycles — never allow it to run dry.
  6. Move to the next caliper (closer to master) and repeat until all calipers are clear of air.

Step 6 – Final flush and reservoir refill

  • Once bleeding finishes and no air is present, fully top the reservoir to the max line with fresh fluid and reinstall the diaphragm and cap.
  • Operate the brakes slowly to confirm firm lever/pedal feel. If spongy, repeat bleeding cycles.

Step 7 – Clean up and inspection

  • Wipe any fluid from calipers, lines, and painted parts with water & rag immediately. Brake fluid can damage paint.
  • Inspect hoses, fittings, and bleeder nipples for corrosion or leaks; replace any cracked or soft hoses on an older Blaster.
  • Dispose of old fluid responsibly at a hazardous-waste facility.

Troubleshooting & tips

  • If you cannot get a firm pedal/lever after multiple bleeds, suspect a leaking master cylinder seal, collapsed hose, or internal caliper issue. Replace suspect components.
  • For stubborn air pockets in ABS or complex systems, a pressure/vacuum bleeder or professional bench-bleed may be required. The Blaster’s simple system usually responds well to manual or vacuum bleeding.
  • Replace the reservoir cap and diaphragm if cracked or brittle; they are inexpensive and vital for preventing contamination.
  • Record the fluid change date — brake fluid typically should be replaced every 1-2 years depending on use and storage conditions.

Final checks

  • Confirm no leaks at bleeder nipples or hose connections. Torque fittings to snug only — do not over-tighten.
  • Test brakes at slow speed in a safe area before riding aggressively.
  • Keep an eye on pedal/lever firmness over the next few rides; if it softens, re-check for air or leaks.

Following this MotoSport-proprietary procedure will keep your 1989 Yamaha Blaster’s brakes reliable. Regular fluid changes and inspections are especially important on older MMY machines to maintain safe performance on trail or track.

Related Shopping Categories

Shop Brake Fluid for a 1989 Yamaha Blaster ATV.

Shop Brake Bleeders for a 1989 Yamaha Blaster ATV.

Shop Brake Pads for a 1989 Yamaha Blaster ATV.

Shop Brake Lines for a 1989 Yamaha Blaster ATV.

Shop Brake Tools for a 1989 Yamaha Blaster 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.