PIN-CARRIER 4773752 - Caterpillar

secondary steering pump will supply oil to the steering system under the following conditions:
The hydraulic and steering pump fails when the machine is moving in a forward direction.
The engine becomes inoperable when the machine is moving in a forward direction.
The engine is in operation and the machine is moving in a forward direction.When the engine is inoperable, the steering pump will not provide the ability to steer the machine. Steering can only be accomplished with the secondary steering system.Note: The secondary steering system will only work when the machine is moving in the forward direction. The secondary steering pump will not supply oil to the steering system when the machine is moving in reverse.The secondary steering system is composed of the following main components:
Secondary steering pump
Steering check valves
Orifice blockOperationWhen the engine is operating, the hydraulic and steering pump supplies oil to the steering control valve. This oil passes through the steering check valve. When the machine is moving in a forward direction, the secondary steering pump also provides oil to the steering system. The amount of oil is restricted by the margin pressure. The margin pressure is controlled by the amount of flow through the orifice in the block and the pressure and flow compensator valve. The steering check valves allow oil from the hydraulic and steering pump and oil from the secondary steering pump to be combined. The combined oil flow is supplied to the steering control valve in order to operate the steering cylinders. The steering check valves prevent the flow of oil from flowing back through the other pump in the event of a pump failure.When there is no flow from the hydraulic and steering pump and the machine is moving in a forward direction the secondary steering pump will provide a constant flow of oil in order to steer the machine.The secondary steering pump is driven directly by the transfer gears. The transfer gears are driven by the drive shaft. The drive shaft is driven by the differential. The differential is driven by the final drive. The final drive is driven by the wheels.