Sometimes we get questions from folks wondering why we include syringes with our power disc brake conversion systems and how to use them. This illustrated post explains brake syringes and what to do with them.
We include a plastic syringe with every Power and Manual Disc Brake Conversion Kit. This syringe is the best way to bleed a master cylinder either on the bench or on the vehicle. To begin, plug both ports on the master cylinder with the provided plugs and fill the reservoir of the master cylinder a little more than halfway with a high quality brake fluid. Make sure the rubber tip on the end of the syringe is firmly in place and fill the syringe using the fluid in the reservoir. Remove one of the plugs from the master cylinder and with a full syringe, push the rubber tip of the syringe to the port and slowly inject fluid into the master cylinder. When doing this, you will see a stream of fluid that is filled with bubbles. Toward the end of the injection of fluid, you should see the bubbles start to disappear leaving a steady stream of fluid. Once finished, plug that port and move on to the next port. Once both ports have been done, you have successfully completed the bench bleeding process of your brake system. If room is available, this can be completed on the vehicle as well.
Once the master cylinder has been bled and installed on the vehicle, it is recommended that the combination valve be bled as well. Install the lines between the master cylinder and the combination valve and do the same thing with the front and rear ports on the combination valve.
This will make sure that when you start bleeding the rest of the system, you will then be focusing on removing air from the lines and the calipers therefore making the process a much simpler task.
Hopefully this simple little tool will make the process of bleeding brakes a much simpler and less painful process.