Daewoo Solar 225LC-V, Shop Manual

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S0702170K
Page 9
Hydraulic System Troubleshooting, Testing and
Adjustment
RIGHT SWING OPERATING CIRCUIT
When the swing control lever is pushed to the
right swing position, pilot pressure from the left
side pilot valve is directed to the right side pump
regulator and right half of the control valve.
Output flow from the right pump is then directed
through the PR and SWR ports of the control
valve to the swing motor.
LEFT SWING OPERATING CIRCUIT
When the swing control lever is pushed to the
left swing position, the control valve spool at the
right side of the control valve moves in the
opposite direction and output flow from the right
pump is directed through the PR and SWL ports
of the control valve to the swing motor.
SWING RELIEF VALVE AND MAKE-UP VALVE
Whenever the spool is shifted to the neutral mode during swing operation, the possibility exists that surge
pressure in the circuit - caused by inertial momentum of the upper works and correspondingly reduced
pressure at the opposite motor port - could produce cavitation in the circuit. To keep that from happening, a
285 kg/cm
2
(4,052 psi) relief valve is installed in the swing motor and a large-capacity make-up valve is
connected to the entrance port of the hydraulic reservoir, helping maintain acceptable pressures on both
sides of the circuit.
TRAVEL OPERATING CIRCUIT
Output flow from both halves of the pump assembly is directed to the right and left travel motors through
the right and left sides of the control valve, and the upper works center joint.
PUMP(R)
PR
CONTROL
VALVE(L)
CONTROL
VALVE(R)
SW SWD
TL
ARS1620L
PILOT VALVE
Figure 8
PUMP(R)
PR
CONTROL
VALVE(L)
CONTROL
VALVE(R)
SW SWD
TL
ARS1610L
PILOT VALVE
Figure 9