BRAKE SYSTEM AND METHOD FOR OPERATING SUCH A BRAKE SYSTEM

A brake system for a motor vehicle with at least four hydraulically activated wheel brakes. Each of the wheel brakes has a first electrically activated wheel valve which is open when de-energized and a second electrically activated wheel valve which is closed when de-energized, a first electrically activated pressure source, connected to the first wheel valves via a first brake supply line. Arranged in the first brake supply line is an electrically activated circuit isolating valve by which two of the first wheel valves can be hydraulically disconnected from the first pressure source, a second electrically activated pressure source, and a pressure medium reservoir vessel at atmospheric pressure. The circuit isolating valve is designed to be open when de-energized, and the second electrically activated pressure source is connected to the second wheel valves via a second brake supply line. A method for operating the brake system is also disclosed.