Abstract: A cut-off valve for power steering systems, especially for automobiles, includes a source of a pressure and a container, and is used for limiting a pressure in at least one pressure chamber. The cut-off valve also includes a closing body, which may be adjusted against the force of a spring and a fixed throttling point, which is located in a connecting line between the pressure chamber that is subjected to a first pressure and a pressure chamber that is subjected to a second pressure. The cross-section of the throttling point may be regulated without being disassembled from the outside. By altering the cross-section of the throttle point, it is possible to reduce the width of the tolerance zone or the width of the hysteresis of the valve characteristics to approximately half of the original size.