A brake system includes a single chamber power transmission unit, a plurality of wheel brakes, and an iso/dump control valve arrangement associated with each wheel brake of the plurality of wheel brakes. A reservoir is hydraulically connected to the single chamber power transmission unit and to each of the iso/dump control valve arrangements. A pump piston is associated with at least one wheel brake. The pump piston is driven by a second electric motor for selectively providing pressurized hydraulic fluid from the reservoir to the iso/dump control valve arrangement of the at least one associated wheel brake. First and second switching valves are provided, and are two-position, three-way type valves, each hydraulically interposed between at least one iso/dump control valve arrangement and both of a selected pump piston and the output line of the single chamber power transmission unit. First and second electronic control units are provided.