The steering and braking systems used on the all-hydraulic JD-570 articulating grader were designed with the safety of the operator in mind. These systems are given priority over the other related hydraulic systems on the grader through the use of a priority valve. An accumulator is provided to store hydraulic energy for the steering and braking systems in the event of a power failure. In addition, the brake valve is capable of acting as a pump to supply pressure oil to the service brakes, if required. A mechanically actuated secondary brake effective on all four tandem wheels is also provided.