Method for operating a braking device for a hydraulically braked towing vehicle

The method involves coupling a towing vehicle with a pneumatically limited hanger, and pneumatically-operating a hydraulic activated and complemented trailer control valve (4) by pneumatic pressure. Hydraulic braking pressure is generated by a brake actuator (8) for a service brake tube of the drawing vehicle. A piston area in the trailer control valve is loaded by the hydraulic braking pressure. The pneumatic pressure is forward controlled by the trailer control valve and is regulated dependent driving operating conditions during driving operation of the pneumatic pressure.