A steering-shaft train between the steering handle and steered vehicle wheels of a vehicle steering system includes an input shaft on the side of the handle and an output shaft on the side of the wheels, as well as a transmitting device, which motively couples these shafts at a transmission ratio controllable by a motor that is mounted in a self-locking manner or arranged to be self-locking. A mechanical control device may comprise a valve actuator for fluid flow control devices. of a passage in the first fluid chamber. The slurries can be stabilized where the solids show little settling from suspension. The sealing gasket contacts the first cover to prevent undesired leakage of the developer therebetween. The front rotating shaft has a plurality of outer locking pins and the rear rotating shaft has a plurality of inner locking pins.