Technique for determining a wear valve, which indicates wear of a friction lining of a vehicle brake

A method for operating a vehicle brake system of a vehicle, wherein the vehicle brake system comprises at least one vehicle brake, wherein the vehicle brake includes a service brake having an actuating piston which, in order to generate a braking force by the action of a hydraulic pressure, is movable into an operating position, in which the actuating piston presses a friction lining against a rotating brake disc, and wherein the vehicle brake further comprises a parking brake unit, that is designed to apply a braking force acting on the brake disc, characterized in that it is supported against the actuating piston to press the friction lining against the brake disc, wherein the method comprises the following steps:

• to determine a first wear value that indicates wear of the friction lining of the vehicle brake, by taking into account at least one parameter of the operational history of the vehicle,
• in dependence upon whether the first wear value meets a predetermined criterion, to perform a measurement of wear of the friction lining by moving the parking brake unit and recording the curve of an operating parameter of the parking brake unit while moving, and
• to determine, based on the measurement, a second wear value, which indicates wear of the friction lining of the vehicle brake.