National Crane Published 08/16/19 Control # 112-05 8-1
500E2 SERVICE MANUAL TROUBLESHOOTING
SECTION 8
TROUBLESHOOTING
SECTION CONTENTS
Hydraulic System Troubleshooting Chart . . . . . . 8-1
Jib Load Limiting Device Troubleshooting . . . . . 8-4
Jib Jack Troubleshooting . . . . . . . . . . . . . . . . . . . . 8-5
Systematic Troubleshooting . . . . . . . . . . . . . . . . . 8-5
HCA Troubleshooting Flow Chart . . . . . . . . . . . . . 8-6
HYDRAULIC SYSTEM TROUBLESHOOTING CHART
Condition Possible Cause Possible Solution
Oil Leakage
Hose fittings loose, worn or damaged.
Oil seal rings deteriorated by excess heat.
Check & replace damaged fittings or "O" Rings.
Torque to manufacturers specifications. Replace oil
seal rings by disassembling Pump unit.
Bolt loose or its sealing area deteriorated
by corrosion.
(a) Loosen then tighten single bolt to torque
specification.
(b) Replace bolt.
Shaft seal worn or damaged.
Remove seal carrier from pump. - Remove
damaged seal from seal carrier.
If shaft is worn, install new seal in the inner position.
Reinstall seal carrier.
No Flow from Pump (If
pump does not prime
in 30 seconds STOP!)
Pump not installed correctly.
Check proper drive rotation. Make sure pump shaft
is turning (i.e. drive coupling is engaged). Check for
sources of suction leaks, inlet flange tight? Pinched
o-rings?
Pump not getting oil.
Can't Build Any Pressure
Flow has an unrestricted path.
Make sure reservoir is full of oil.
Is it an open circuit to the reservoir.
Internal leakage in cylinders, valves,
motors or pumps.
Repair component.
No response to control
Overload system inoperative.
Insure overload system is working properly and
Anti-Two-Block/Overload solenoid is powered.
Load too heavy. Check Capacity Chart.
PTO not engaged. Engage PTO.
Low hydraulic fluid supply. Check and fill as required.
Suction line blocked. Drain tank and hose and remove blockage.
Broken hydraulic pressure line. Replace as required.
Defective hydraulic pump. See Pump Service Manual.
Incorrect relief valve setting. Adjust relief.
Relief valve sticking. Clean relief.
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