Daewoo Solar 470LC-V, Shop Manual

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S0702190K
Page 11
Hydraulic System Troubleshooting, Testing and
Adjustment
PROCEDURAL TROUBLESHOOTING BASELINE
RECOMMENDATIONS
INITIAL CHECKS AND TESTS TO ESTABLISH OPERATING
CONDITION OF THE EXCAVATOR
Triage Summary
An excavator that fails to deliver designed performance should be checked for the following:
• Hydraulic flow, first, and
• Hydraulic pressure, afterwards, in a specified order of priority through different points of the
system.
To verify adequate available hydraulic flow, before any other tests are performed through the circuit:
Check engine operation -
• at 2,190 RPM with no load
• at 2,000 RPM stall load
If engine RPM drops excessively with a load or fails to surpass rated speed (1,900 RPM), performance
problems may be due to inadequate hydraulic flow caused by lagging rotational speed.
NOTE: Verify actual flow on the excavator against rated performance, with a flow meter.
If engine tests meet specifications and adequate torque and horsepower are available at the pump drive
flex coupling, pull out the electrical tray under the operator’s seat to inspect the self-diagnostic display.
If the EPOS trouble code display is clear, check hydraulic functions in the following sequence:
• Pilot pressure
• Negacon, negative control pressure
• Main relief pressure (front and rear pump)
• Swing pressure
• Port relief pressure (individual control functions; crowd, bucket, boom, travel)
• Power boost circuit
• Standard performance tests; cylinder speed, hydraulic motor (travel and swing) speed, cylinder
oil-tightness "permissible drift" test
NOTE: System specification performance tests of individual activator function are determined by
flow rate through the component or circuit, not the control pressure or system pressure
available to the actuator. Poor flow through the individual circuit may indicate that the
component is worn beyond tolerance limits, while all other hydraulic functions are
adequate.
IMPORTANT
It is suggested that the troubleshooter maintain the testing sequence of the preceding list.
Checks and adjustments nearer the middle or the end of the list may depend on adequate
functioning of systems tested nearer the top of the list.