MALAGA
793C OFF HIGHWAY TRUCK
Adolfo
August 1998
4. STEERING
1. Components Layout
2. Operation
CHAPTER : STEERING
4-2 Page:
1
UPPER SIGHT GAUGE
2
LOWER SIGHT GAUGE
3
VACUUM BREAKER/RELIEF VALVE/PRESSURE
RELEASE BUTTON
4
CASE DRAIN OIL FILTER
5
MAIN STEERING OIL FILTER
6
AUXILIARY POWER UNIT ADAPTER
1
2
3
5
6
4
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-3STEERING
SYSTEM
(789B
AND793B)
NOSTEER/MAXIMUMFLOW SOLENOIDAND RELIEFVALVE RETURN MANIFOLD STEERINGDIRECTIONAL VALVEHANDMETERINGUNIT PUMP SWITCH ACCUMULATOR SWITCH R L P T LS PISTONPUMP ACCUMULATOR CHARGING VALVE SUPPLY MANIFOLD DIRECTIONAL SPOOL AMPLIFIER SPOOL BACKPRESSURE VALVE CONBINER CHECKSPOOL PRIORITY SPOOL
CHAPTER : STEERING
4-4 Page:
1
STEERING PUMP
2
LOAD SENSING CONTROLLER
3
PUMP OUTPUT PRESSURE TAP
4
STEERING PRESSURE SWITCH
1
2
3
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-5 PUMP OUTPUT LOAD SENSING PRESSURE ACTUATOR PISTON LOAD SENSING CONTROLLER SWASHPLATE PISTON FLOW COMPENSATORDURING CHARGING (CUT-IN)
STEERING PUMP
ACCUMULATOR CHARGING VALVE TO ACCUMULATORS FROM ACCUMULATORS CUT-OUT VALVE CUT-IN VALVE HIGH PRESSURE CUTOFF VALVECHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-6FROM PUMP TO PUMP CONTROL SIGNAL PORT CUT-OUT VALVE CUT-IN VALVE FROM ACCUMULATOR TO TANK FEEDBACK ORIFICE
ACCUMULATOR CHARGE VALVE
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-7 PUMP OUTPUT LOAD SENSING PRESSURE LOAD SENSING CONTROLLER FLOW COMPENSATOR SWASHPLATE PISTON ACTUATOR PISTONLOW PRESSURE STANDBY (CUT-OUT)
STEERING PUMP
TO ACCUMULATORS FROM ACCUMULATORS ACCUMULATOR CHARGING VALVE CUT-OUT VALVE CUT-IN VALVE HIGH PRESSURE CUTOFF VALVECHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-8FROM PUMP TO PUMP CONTROL SIGNAL PORT CUT-OUT VALVE CUT-IN VALVE FROM ACCUMULATOR TO TANK FEEDBACK ORIFICE
ACCUMULATOR CHARGE VALVE
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-9FROM PUMP TO PUMP CONTROL SIGNAL PORT CUT-OUT VALVE CUT-IN VALVE FROM ACCUMULATOR TO TANK FEEDBACK ORIFICE
ACCUMULATOR CHARGE VALVE
CHAPTER : STEERING
4-10 Page:
1
CHECK VALVE
2
SOLENOID AND RELIEF VALVE MANIFOLD
3
ACCUMULATOR CHARGING VALVE
4
STEERING DIRECTIONAL VALVE
5
STEERING SYSTEM PRESSURE TAP
1
2
3
4
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-11BACK-UP RELIEF
VALVE
BLEED DOWN
SOLENOID
TO TANK
SUPPLY FROM PUMP
AND ACCUMULATORS
CHAPTER : STEERING
4-12 Page:
1
CHECK VALVE
2
ACCUMULATOR PRESSURE SWITCH
3
BLEED DOWN SOLENOID
4
BACKUP RELIEF VALVE
5
STEERING SOS TAP
6
SUPPLEMENTAL STEERING CONNECTOR
1
2
3
4
5
6
CHAPTER : STEERING
4-13 Page:
1
SHUTDOWN CONTROL FOR ACCUMULATOR BLEED
DOWN
HOLDS SOLENOID OPEN FOR 70 SECS AFTER
SHUTDOWN
LOCATED UNDERNEATH CENTRE CONSOLE
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-14STEERING
DIRECTIONAL
VALVE
R L P T LSBACK
PRESSURE
VALVE
RELIEF/MAKEUP
VALVE
DIRECTIONAL
SPOOL
COMBINER/CHECK
SPOOL
PRIORITY
SPOOL
TANK
PUMP
AMPLIFIER
SPOOL
NO
STEER
HAND
METERING
UNIT
STEERING
SYSTEM
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-15STEERING DIRECTIONAL VALVE
R L
P
T LS
BACK PRESSURE VALVE
RELIEF/MAKEUP VALVE
DIRECTIONAL SPOOL
COMBINER/CHECK SPOOL
PRIORITY SPOOL
TANK
PUMP
AMPLIFIER SPOOL
RIGHT TURN
HAND METERING UNIT
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-16 RELIEF/MAKEUP VALVE LEFT TURNCYLINDER BACK PRESSURE VALVE
LEFT TURN PILOT OIL
AMPLIFIER SPOOL RIGHT TURN PILOT OIL
COMBINER/CHECK SPOOL
LOAD SENSING PORT
FROM ACCUMULATOR
PRIORITY SPOOL
STEERING DIRECTIONAL VALVE
RIGHT TURN CYLINDER
RELIEF/MAKEUP VALVE
HAND METERING UNIT SUPPLY AND THERMAL BLEED
NO TURN
CHAPTER : STEERING
793C OFF HIGHW
A
Y
TRUCK
4-17 AMPLIFIER SPOOL BACK PRESSURE VALVELEFT TURN PILOT OIL RIGHT TURN PILOT OIL
COMBINER/CHECK SPOOL
LOAD SENSING PORT
FROM ACCUMULATOR
HAND METERING UNIT SUPPLY AND
THERMAL BLEED
PRIORITY SPOOL
STEERING DIRECTIONAL VALVE
RIGHT TURN
RELIEF/MAKEUP VALVE LEFT TURN CYLINDER RIGHT TURN CYLINDER RELIEF/MAKEUP VALVE TO TANKCHAPTER : STEERING
4-18 Page:
STEERING DIRECTIONAL VALVE
1
PRESSURE TAP TO MEASURE CUT IN & CUT OUT
CHAPTER : STEERING
4-19 Page:
