Daewoo Solar 470LC-V, Shop Manual

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S0702190K
Page 22 Hydraulic System Troubleshooting, Testing and
Adjustment
SWING SYSTEM TROUBLESHOOTING
PRECAUTIONS/INITIAL CHECKS
1. Stop work. Release all weight or any type of load safely before proceeding. Avoid risking injury or
adding to damage.
2. Turn off engine and disengage control functions until initial tests are ready to be made.
Stop the machine, put the boom and arm in the inoperative (overnight park) position and begin by making
the fastest, simplest checks first:
• Check oil level.
• Check for overheating, oil leaks, external oil cooler clogging or broken fan belt. Consult service
record for prior repair/service work.
• Drain some tank oil to a clean, clear container. Look for metal shavings/grit, cloudiness/water or
foam/air bubbles in the oil.
• Check for wobble through the engine/pump flex coupling. Run engine with the pump input
hydraulic power control nut turned to the lowest power to check the engine.
• Investigate unusual operating noises or vibration. Check for loose bolts, connections.
SWING RELIEF VALVE CHECKING AND ADJUSTMENT
Make a check of operating pressures through the swing relief valve if:
• The swing motor fails to turn.
• Swings in one direction only.
• Swings but continues to coast.
• There is drifting on a slope.
1. Check operation by connecting:
A. Two 600 bar (8,700 psi) pressure gauges to the inlet and outlet measuring ports on top of the
swing motor.
Pressure should be between 270 - 280 bar (3,916 - 4,061 psi), with both swing locks engaged.
With swing locks released, during full acceleration and deceleration, pressure should approach
250 bar (3,625 psi) in each direction.
B. Connect a 60 bar (870 psi) pressure gauge at the "SH" port of the hydraulic brake.
Pressure should always stay at or above 4 bar (58 psi) when operating swing, boom or arm.
WARNING
Prevent possible injury and/or loss of operating control. Stop work and park the excavator at the
first indication of:
1. Equipment breakdown
2. Inadequate control response
3. Erratic performance