Abstract: An electronically controllable brake actuation system for motor vehicles is proposed, with a master brake cylinder (2), with a pressureless pressure medium reservoir (3), with a pressure source (20) which can be controlled by means of an electronic control unit (32), by means of which pressure can be applied to the wheel brakes (7, 8, 9, 10) of the vehicle, which can be connected by means of at least one hydraulic connection (11, 14), which can be shut off by means of a separating valve (12, 15), to the master brake cylinder (2), with a device (13, 33) for the recognition of the driver's wish to slow down, and with at least one separating piston arrangement (16) which is connected before the wheel brakes (7-10), where the first chamber (17) of this separating piston arrangement can be connected to the master brake cylinder (2), and its second chamber (19) can be connected through a valve device (27) to the pressure source (20) or to the pressure medium reservoir (3).