18995880 A description this invention relates generally to a steering system and more particularly to a hydraulic servo steering system having a pair of pilot operated valves which permit the steering system to be operated as 34 jerk 34 steering in the event of a line failure in the servo circuit many hydraulic steering systems have a pilot operated steering valve for controlling the flow of pressurized fluid from a pump to one or more steering cylinders in response to pilot fluid directed thereto from a hand metering unit with such systems rotation of the steering wheel one revolution for example directs a preselected volume of pilot fluid to one end of the steering valve to shift it a preselected distance a servo circuit is sometimes included as an integral part of such steering systems for causing the steering valve to return to its centered position in response to turning of the vehicle so that one turn of the steering wheel will provide a proportionate degree of turning of the vehicle the servo circuit has a followup servo mechanism connected between a pair of members which move relative to one another upon the vehicle being turned the followup servo mechanism can be either a linear or rotary motor with its opposite ends or sides being in fluid communication with the.