Some of our customers wonder why we include syringes with our disc brake conversion kits and how to use them. This illustrated post explains brake system syringes and how to use them.
We include a plastic syringe with every Power and Manual Disc Brake Conversion Kit because this handy tool 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 brake fluid injection, you'll see the bubbles disappearing, leaving a steady stream of fluid. Once finished, plug the port and move on to the next. Once both ports have been done, the bench bleeding process is complete. 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, we recommend bleeding the combination valve 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.