MASTER CYLINDER UNIT

To improve a master unit, in particular for a hydraulic brake system, comprising a housing body, a piston which is arranged movably in the housing body between an initial position and a pressure position, a pressure chamber delimited by the housing body and the piston, a storage chamber connected to the pressure chamber via a connecting channel for storing hydraulic medium, a valve unit which in an open position permits the connection between the storage chamber and the pressure chamber and in a closed position separates this connection, as well as a connecting opening for forwarding pressurized hydraulic medium from the pressure chamber to, for example, a connected hydraulic brake cylinder, in such a way that escape of air bubbles from the pressure chamber is made possible in a simple manner, it is proposed that in a functional orientation of the master unit, the connecting channel opens into an end region of the pressure chamber which is highest with respect to a direction of gravity.