The invention relates to an electrical power steering system for a motor vehicle with a steering housing, in which a gear system is arranged, wherein a bar mounted such as to be displaceable longitudinally in the housing is a gear element for actuating steerable wheels, and wherein the steering housing is closed off by at least one folding bellows element, which is secured on one side to the steering housing and on the other side to the bar. Rapid pressure compensation in the event of temperature change is guaranteed, because a hose is connected at one end such as to communicate with the interior volumes of the steering housing, and when in operation is secured at a second free end above the steering housing.