Subtopic: Steering and hydraulic control systems used in tractors
Question Statement:
In tractor hydrostatic power steering systems incorporating an 'Orbitrol' steering control unit:
Options:
(A) The steering unit functions as a rotary metering valve during powered operation and automatically operates as a manual hand pump to provide emergency steering if the engine dies
(B) Mechanical drag links physically connect the steering column to the front kingpins with zero hydraulic assist
(C) The steering wheel is mechanically locked to the engine camshaft
(D) Turning is executed exclusively by pulsing the rear axle brakes
Answer Key:
A
Step-by-Step Solution & Explanation
The Orbitrol hydrostatic steering unit eliminates mechanical linkages between steering wheel and axle. It metered hydraulic fluid to steering cylinders, and contains check valves enabling the gerotor unit to act as a manual hand pump for emergency manual control if hydraulic pressure fails.