Master Cylinders can be a little tricky to setup during installation. We have a few tips below that can help with common issues during the initial setup process. It is important to remove air bubbles from the cavities inside the reservoir as they can cause flow issues.

Check the bolt on the plunger rod is not over-tightened, the connection should pivot freely.

Check the two O-rings are in place behind the blue ‘Autoback‘ bung and NOT damaged.

Sometimes if left for a long period of time the plunger can stick due to water residue/condensation. Trailparts recommends the plunger be pumped occasionally when in storage etc

If you have issue bleeding the brake lines. Refer to the below method to remove air bubbles from the master cylinder.

Air bubbles in the Autoback chamber

Air bubbles preventing flow to brake lines

  1. Unscrew the blue bung 1 to 1.5 turns
  2. Pump the push rod.
  3. You should see some small bubbles coming out of the internal hole in the reservoir on the Autoback side.
  1. Unscrew brake line if already connected
  2. Fill reservoir with brake fluid
  3. Push plunger in
  4. Put finger over outlet to create vacuum
  5. Let plunger release, or pull plunger out
  6. Repeat a few times
  7. Brake fluid should flow