National Crane Published 08/16/19 Control # 112-05 8-3
500E2 SERVICE MANUAL TROUBLESHOOTING
Excessive pump noise
during operation
Excessive pump speed. Adjust foot throttle or check for too high PTO ratio.
Low oil temperature. Allow unit to warm up.
Low hydraulic oil supply. Check and fill.
Suction line kinked, collapsed or blocked. Clear blockage.
Pump Cavitation Check for loose clamps.
Hydraulic oil too thick. Warm oil or use oil more applicable to environment.
Relief valve chattering. Dirt in relief valve or damaged relief.
Hydraulic tubing vibration. Check for loose tubing.
Tank breather plugged. Clean breather.
Cylinders drift
Not getting oil to cylinders. Clean and replace as required.
Worn or damaged piston seals. Replace as required.
Air in hydraulic oil. Cycle operate crane cylinder to remove air.
Loose holding valve. Tighten valve.
Dirt in holding or check valve. Clean valve.
Hoist will not lift or hold
load
Load too heavy.
Check load and change to applicable multipart
reeving.
Relief valve setting too low. Check and adjust if required.
Motor worn excessively. Replace motor.
Counterbalance valve defective or
leaking.
Clean and replace as necessary.
Anti-two-block system defective. Repair anti-two-block system.
Brake worn out. Repair or replace brake.
Hoist gearbox heats
Gearbox grease low. Check and fill as required.
Duty cycle too high. Reduce cycle time or speed of hoist.
Boom chatters during
extension/retraction or
doesn't proportion
properly
Boom sections need lubrication. Grease boom.
Wear pads not shimmed correctly. Re-shim as described in boom assembly section.
Worn wear pads. Replace pads.
Extension cables out of adjustment. Readjust cables and tension properly.
Extend or retract cables broken. Disassemble and inspect and replace cables.
Boom will not extend
Proportioning cables not attached. Reconnect, replace and/or adjust cables.
Anti-two-block system shut down. Lower hook, and extend load.
Defective anti-two-block system Check anti-two-block system; repair if defective.
HYDRAULIC SYSTEM TROUBLESHOOTING CHART
Condition Possible Cause Possible Solution
To Next Page
Loading...
