Antilock Brakes / Traction Control Systems: Service and Repair

Preparatory Work

- Remove rear left inner fender.

- Connect bleeding device to PSD hydraulic reservoir.

- Disconnect vent line (if present).

- Build up bleed pressure (approx. 1.5 - 2.0 bar).

1. Bleeding the pressure reservoir.

To charge the pressure reservoir, the ignition must be switched on. When the pressure reservoir has been charged, the pump cuts out; reservoir pressure is then approx. 180 bar.

- Connect the bleed cylinder.

- Switch off the ignition.

- Carefully open the bleed valve and allow the pressure level to drop gradually. While this is being done, the ignition must remain switched off to ensure that the pressure is completely reduced and the air is expelled from the reservoir.

- Repeat this procedure several times, making sure that the ignition is switched on/off at the appropriate stages in the procedure.

2. Bleeding the valve block and the locking line to the lock slave cylinder.

- Connect the 9288 System Tester.

- Switch the ignition "ON".

- Connect the bleed cylinder to the bleed screw on the slave cylinder.

- Open the bleed screw on the slave cylinder.

- Select "Stall PSD Bleeding" and actuate repeatedly until no further air emerges.

- The bleeding device must remain switched on, because the reservoir volume is used up rapidly.

- After this, dose the bleed screw on the slave cylinder.

- Select "Stop Bleeding" and "Start Pressure Reduction" on the system tester.

- Switch off the bleeding device and disconnect it.

- Screw on the reservoir cover.

- Open the vent line at the reservoir again (if present).

- Check level in the reservoir. The fluid must be approx. 1 cm above the step in the reservoir body or between the markings (with the pressure reservoir charged).