SWITCH GP-TEMPERATURE 3E7504 - Caterpillar

The standard steering system consists of the following:gear pump, steering priority valve, steering control valve and steering cylinder.The steering wheel is the primary means of steering the machine. An optional joystick steering system is available, which allows the thumbwheel on the right joystick to be used for steering the machine. This system is only functional in the first speed range and is discussed in "Joystick Steering (Optional)".
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(15) Gear pump (pilot, brake, steering, and auxiliary tool)Gear pump (15) supplies oil to the following components:
Pilot system
Brake system
Steering system
Medium pressure attachment
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View Under the Cab (6) Steering control valveSteering control valve (6) is located below the cab at the front of the machine.
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Steering Priority Valve (11) Load sense line from steering control valve to steering priority valve. - (LS) (12) Pressure line from steering priority valve to steering control valve at pressure inlet. - (CF) (13) Steering priority valve (14) Line from gear pump (pilot, brake, steering, and auxiliary tool) (P)Pump (15) sends oil through line (14) to steering priority valve (13). Oil flows through steering priority valve (13) to line (12) and to steering control valve (6) at the pressure inlet. When the steering wheel is turned, more flow is needed for the steering. The wheel being turned causes a momentary drop in pressure in the steering control valve supply passage. Pressure on the right side of the priority spool is also reduced. Line (11) sends a load sense signal back to the steering priority valve (13). The load sense signal shifts the spool to the right. The right shift causes flow to be given to the steering control valve over the other gear pump (15) functions such as braking, medium pressure, and auxiliary tools. As long as the steering wheel is not operated, all oil from the pump goes through the priority valve port "EF" to the other functions (brake, pilot manifold, medium pressure). The priority valve shares oil to the steering control valve depending on the steering wheel operation speed.When the steering wheel is turned, oil flows through lines (3) and (4) to steering cylinder (5). When the steering wheel is turned to the left, oil is sent through line (3) and causes the cylinder to shift to the right. Oil in line (4) is directed back to the tank. When the steering wheel is turned to the right, oil is sent through line (4) and causes the cylinder to shift to the left. Oil in line (3) is directed back to the tank.Note: Refer to Systems Operation, "Control Valve (Steering)" in this manual for a complete description of the operation of steering control valve (6) and steering priority valve (13) .Joystick Steering (Optional)
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(1) Hydraulic line to transmission (2) Hydraulic line to modulation valve (3) Modulation valve (4) Pilot line - first gear valve (5) First gear valve (6) First gear electrical solenoid (7) Right steering line check valve (8) Right travel hydraulic line (9) Left travel hydraulic line (10) Left steering line check valve