A filling machine assembly (10) for filling a beverage container (12), such as a bottle or can, with a beverage such as carbonated drinks, juice or water. The filling machine (10) includes a support housing (14) for supplying the beverage to be discharged into the container (12). A valve housing (22) is mounted to the bottom of the support housing (14) for controlling the discharge of the beverage and a control device (24) is mounted to the top of the support housing (14). The control device (24) has outer walls (26) defining a working chamber (28) having a top and a bottom. A vent tube (30) has a first end disposed within the working chamber (28) of the control device (24) and a second end extending into the valve housing (22). A piston (38) is secured to the first end of the vent tube (30) within the working chamber (28) for moving the vent tube (30) a predetermined stroke between a filling position and a non-use position. The assembly is characterized by a first input port (70) disposed above the piston (38) at the top of the working chamber (28) and a second input port (72) disposed below the piston (38) at the bottom of the working chamber (28) whereby a fluid medium may pass through the first (70) and second (72) input ports to move the piston (38) and the vent tube (30) between the filling and non-use positions.