Venting DSC with the DIS tester

Primary circuit: In the DSC hydraulic unit, air bubbles can adhere to the edges and valves, and these cannot be removed by rinsing with the brake fluid replacement device. The vibrations that occur during venting with the DIS tester loosen the air bubbles.

Secondary circuit: In the normal case (DSC does not intervene), the secondary circuit of the DSC hydraulic unit is closed, so air it contains cannot escape on rinsing with the brake fluid replacement device. On venting with the DIS tester, the return pump, the exhaust and high-pressure switching valves are activated during rinsing so that also the secondary circuit is vented.

Following replacement and repair of the following parts, the DIS tester must be used for venting:

• Hydraulic unit
  
• Master brake cylinder
  
• Components and/or connecting lines located between the hydraulic control unit and master brake cylinder
  

Operations:

On the DSC8, operations 3 ... 7 are to be performed in the order rear right, rear left, front right and front left

For the DSC Mk60, the operations are specified explicitly in the test module.

1. Connect the brake fluid replacement device and switch online;(The fill pressure must not exceed 2 bar)
   
2. Fully rinse the brake system
   
3. Attach the venting bottle to the vent valve
   
4. Open the vent valve
   
5. Start venting with the DIS tester with opened vent valve
   
6. After completion of the venting, press the brake pedal approx. 5 times down as far as it will go; the brake fluid that escapes must be free of bubbles
   
7. Close the vent valve
   
8. Remove the brake fluid replacement device
   

Note:

A second person is required for this task