Abstract: A wheeled vehicle which has two members connected by an upright joint has a pair of hydraulic steering jacks coupled between the members on opposite sides of the joint, and the vehicle is steered by normally causing both jacks to pivot the members under the control of a steering wheel. The hydraulic steering system utilizes a constant displacement pump driven by the vehicle engine, and includes a follow-up means which senses the pivoting movement and deactivates the jacks when turning of the steering wheel ceases, so the operator may steer the vehicle by manipulating the wheel in a conventional manner. Selector valve means in the hydraulic system functions to automatically direct all or nearly all of the fluid to one jack if pump output is insufficient to drive both jacks as fast as is called for by the operator's rotation of the steering wheel.