Bleeding the Front and Rear Brakes on a 2021 Triumph Tiger 900 GT

Shop parts for a 2021 Triumph Tiger 900 GT Motorcycle.

The 2021 Triumph Tiger 900 GT is a road-biased adventure tourer with strong hydraulic disc brakes at both wheels and ABS. The front brake is operated by the right-hand lever through a master cylinder and reservoir on the handlebar. The rear brake is operated by the foot pedal through a separate master cylinder and reservoir. Bleeding both circuits flushes out moisture-laden fluid and removes air, so the lever stays firm and the brakes respond the same way every time.

Why Bleeding Is Part of Regular Maintenance

Brake fluid absorbs moisture from the air over time. That lowers its boiling point, and during hard use, such as a fast run through mountain curves or a long descent with luggage, old fluid can boil. The resulting vapor compresses, giving you a soft lever and fading brakes. Many riders refresh the fluid on a regular schedule to prevent that.

Signs that a bleed is due now:

  • A spongy lever, or one that pulls closer to the grip than it used to
  • A soft or sinking rear pedal
  • Dark or cloudy fluid in a reservoir
  • Recent work that opened the system, such as new lines, caliper service, or master cylinder repair

Gather Your Supplies

  • Fresh brake fluid of the type marked on the master cylinder reservoir cap, from a sealed container
  • A box-end wrench that fits the bleeder valves
  • Clear tubing that fits snugly over the bleeder
  • A catch bottle
  • A syringe or turkey baster
  • A screwdriver or driver for the reservoir caps
  • Rags or shop towels

A one-way check-valve bleeder or vacuum bleeder lets you work alone; otherwise, recruit a helper for the lever and pedal.

Prep the Bike

Support the bike securely upright on its center stand or a paddock stand. Turn the handlebars until the front reservoir is level. Cover the tank, bodywork, and dash with rags. Most brake fluids damage paint and plastic on contact, so wipe up any spill immediately and rinse with water.

Bleeding Instructions

  1. Remove the front reservoir cap and diaphragm.
  2. Use the syringe to remove most of the old fluid, without letting the reservoir run dry.
  3. Refill with fresh fluid.
  4. Attach the clear tube to the bleeder of the front caliper farthest from the master cylinder and run the other end into the catch bottle.
  5. Squeeze and hold the lever.
  6. Open the bleeder about a quarter turn. Fluid and air will flow out.
  7. Close the bleeder before releasing the lever.
  8. Repeat, topping off the reservoir every few strokes so it never runs low enough to draw air in.
  9. When fresh, clean fluid with no bubbles comes through, close the bleeder.
  10. Bleed the second front caliper the same way, if your bike has one.
  11. Bleed the rear caliper with the foot pedal and rear reservoir.

Common Mistakes

Running a reservoir low is the error that causes the most trouble. On an ABS bike, air drawn into the master cylinder can travel toward the ABS unit, where a normal bleed may not reach it. Releasing the lever while the bleeder is still open can pull air in at the caliper. And a loose tube on the bleeder can draw air in around the nipple, making it seem like the bubbles will never stop.

Finishing Up

Tighten each bleeder snugly without overtightening. Fill the reservoirs to the correct level marks, reinstall the diaphragms and caps, and clean away any spilled fluid. Check the bleeders and banjo fittings for leaks. Never reuse fluid from the catch bottle; dispose of it properly.

Testing

The lever and pedal should feel firm and consistent, and neither should slowly sink under steady pressure. Spin both wheels to confirm the brakes are not dragging. Test the brakes at low speed in a safe area before riding normally.

When to Take It to a Shop

Have the bike inspected if the lever will not firm up after several bleeds, only firms up after pumping, keeps producing bubbles, or if a master cylinder or caliper is leaking. If a reservoir ran dry or the ABS unit or its lines were disconnected, air may have entered the ABS unit, and the system may require a dealer-level procedure or diagnostic tool.

Related Shopping Categories

Shop Brake Fluid for a 2021 Triumph Tiger 900 GT Motorcycle.

Shop Brake Lines for a 2021 Triumph Tiger 900 GT Motorcycle.

Shop Brake Pads for a 2021 Triumph Tiger 900 GT Motorcycle.

Shop Stands for a 2021 Triumph Tiger 900 GT Motorcycle.

Shop Brake Tools for a 2021 Triumph Tiger 900 GT Motorcycle.

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.