Special bleeding routine for selective actuation of solenoid valves and pump motor during bleeding.
Only to be used when air locks are present in the hydraulic unit auxiliary circuit.
The intention is to establish whether air locks are present in the auxiliary hydraulic unit secondary circuit, e.g. caused by an empty reservoir, leaks in the pipe between the main brake cylinder and the unit, cracks in brake pipes when the brake pedal is activated, or if it is suspected that there is still air in the system after normal, repeated bleeding (soft pedal).
Brake fluid replacement, brake system component repairs, the removal or replacement of the hydraulic unit or the main brake cylinder and individual problems such as external leaks or a soft brake pedal are not considered to be exceptional cases. In these cases, normal bleeding of the brake system should be performed without the HHT.
- A 2nd operator is required to support the brake.
- During exceptional bleeding, it must be ensured that there is always enough brake fluid in the expansion reservoir.
- Only filled hydraulic units are supplied by spare parts depot.
- Before starting the procedure, set the ALB control module to full load and block.
After selecting the wheel brake that is to be bled from the sub-menu, progress is displayed in the HHT display:
Exceptional bleeding sub-menu:
6.1 Rear right wheel
6.2 Front left wheel
6.3 Rear left wheel
6.4 Front right wheel