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Replacing brake fluid and bleeding brakes

Required Tools for the Procedure:

  • Phillips screwdriver – for the front brake reservoir
  • Hex key – for the rear brake reservoir
  • 8 mm wrench
  • Transparent silicone tube ~ 50-100 cm
  • Syringe, preferably larger, around 50 – 60 ml
  • Container for old fluid
  • Brake fluid DOT4

Brake Fluid Replacement​

  1. Unscrew the two screws on the front brake cylinder reservoir using a Phillips screwdriver.
  2. Extract the fluid with a syringe, leaving a small layer at the bottom. It is crucial to prevent air from entering the hole at the bottom of the reservoir!
  3. Remove the rubber cap from the bleeder valve on the front caliper, attach the transparent silicone tube, and submerge the tube into the container.
  4. Loosen the bleeder valve counterclockwise with an 8 mm wrench.
  5. Pour new fluid into the reservoir, then by pressing the front brake lever, expel the old brake fluid from the front circuit. It is important not to completely empty the reservoir to avoid introducing air into the brake system. Remember to keep adding new brake fluid to the reservoir.
  6. Once the brake fluid in the circuit is completely replaced, close the bleeder valve on the caliper by turning it clockwise. Be cautious not to overtighten, as the metal is very soft.

Brake Bleeding​

  1. After replacing the brake fluid, it is essential to bleed the brakes. The reservoir should contain new brake fluid, the silicone tube should already be attached to the bleeder valve and submerged in the fluid container. You may need an assistant for the next operation, although with sufficient skill, it can be done solo.
  2. The bleeder valve is closed. Use the brake lever to make 3 - 4 full compressions (it is important to fully release the lever and then press it completely to the stop). Hold the lever in the pressed position on the last compression.
  3. Open the bleeder valve. You will feel the brake lever become soft and sink. You will see bubbles begin to exit through the tube along with the brake fluid.
  4. Close the bleeder valve.
  5. Repeat steps 1 – 3 until all bubbles disappear from the exiting brake fluid. Remember to monitor the fluid level and top up as necessary.
  6. Top up the fluid in the reservoir to the required level and close the lid, tightening it.

Alternative Bleeding Method​

(for brakes installed on some pit bikes, such as PitsterPro)

  1. Once there are no bubbles left in the brake system, press the brake lever.
  2. Open the bleeder valve.
  3. Release the brake lever.
  4. Close the bleeder valve.
  5. In this process, the piston extends a few millimeters from the caliper, and the brakes begin to engage.

Brake Pad Compatibility​

For calipers installed on PitsterPro pit bikes, the front pads from Nissin for the Honda Lead AF48 moped are suitable, and the rear ones from Honda Dio.