Daewoo Solar 420LC-V, Manual

Page: 27 / 151

Page 26
Hydraulic System Troubleshooting, Testing and
Adjustment
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Sluggish performance of all
hydraulic functions - attachment,
swing and travel. Main pump(s) damaged or worn Repair or replace
Main relief valve pressure off Readjust pressure
Low oil level in hydraulic system Refill
Hydraulic reservoir intake
strainer clogged
Clean
Pump inlet (supply side) piping
or hose allowing air into
hydraulic system
Tighten connection
Oil temperature abnormally
high. Oil cooler clogged or air
circulation to cooler blocked
Clean
Cooling fan belt tension too
loose
Readjust belt tension
Relief valve set too low Readjust valve
Relief valve in constant use
Reduce or slow work load or
cycling rate
Hydraulic oil severely neglected
or incorrect for application
Replace oil
One circuit in hydraulic system
inoperable.
Overload relief valve malfunction Readjust or replace
Oil leak at make-up valve Clean, repair
Control valve spool damaged Repair or replace
Dirt in control valve spool Clean or replace
Actuator (joystick, foot pedal)
damaged or worn
Repair or replace
Internal seal leak in cylinder Repair or replace
Cylinder rod damaged Repair or replace
Pilot valve or piping malfunction Repair or replace
Mechanical linkage frozen,
loose or damaged
Repair or replace
Travel motors inoperable. Center joint damaged. Repair or replace.
Parking brake not releasing. Repair or replace.
Travel motor worn or damaged. Repair or replace.
Travel motor pilot piping
damaged.
Repair or replace.
Travel motors operate very
slowly. Track tension poorly adjusted
Low oil in idlers or rollers.
Readjust tension Refill.
Travel brake dragging. Repair
Track frame out of alignment,
deformed or twisted.
Repair
Swing motor inoperable. Swing brake not releasing. Repair or replace
Relief valve malfunction. Repair or replace
Pilot piping damaged. Repair or replace
Problem Possible Causes Remedies