Troubleshooting Guides; General Hydraulic System Troubleshooting - Manitowoc Grove CD3340B Service Manual

CD3340B/YB4411

TROUBLESHOOTING GUIDES

General Hydraulic System Troubleshooting

Table 4-1
Symptom
Noise (above normal)
Slow operating speeds (All
functions)
No movement when system is
first started.
Loss of movement during
operation.
GROVE
Possible Cause
Air in system.
Low oil supply.
Restriction in pump inlet line.
Dirty oil.
Loose clamps, vibration of hydraulic lines.
Dirt or foreign material in a relief valve.
Broken control valve spool.
Pump bearings worn.
Low engine rpm.
Air leak in pump inlet line.
Air in oil (foam in tank).
Leakage in the load sense relief valve.
Improper load sense relief valve setting.
Leakage in hydraulic swivel.
Control valve not fully actuated.
Improper primary pump pressure.
Faulty pump.
Low oil level.
Air or restriction in inlet line to pump.
Cold oil or wrong weight of oil.
Low oil level.
Vacuum in hydraulic tank.
Restriction or leakage in the relief valve.
Broken hydraulic line.
Bad seal in hydraulic swivel.
Broken gear or shaft in pump.
Published 04/07/2015 Control # 569-00
HYDRAULIC SYSTEM
Remedy
With engine at low rpm, operate all control
functions several times to return the air to
atmosphere through the tank breather.
Add recommended oil.
Remove and clean inlet line to pump.
Change oil and filters. See Maintenance,
page 5-1.
Check and tighten.
Clean or replace the relief valve.
Replace the control valve section.
Replace the bearings or pump.
Increase engine rpm.
Tighten pump inlet line. Replace O-ring
inlet flange.
Check oil level, look for leaks in the
system.
Remove and clean or replace the relief
valve.
Check and adjust relief valve setting.
Replace seals on swivel shaft.
Check spool travel.
Check and adjust pump pressure settings.
Overhaul or replace pump.
Check and add oil.
Check and tighten inlet line. Clear
restriction.
Use correct oil, follow manual warming
procedure.
Check and add oil.
Clean tank filler/breather cap.
Clean or replace the relief valve.
Replace.
Replace seals.
Overhaul or replace.
4
4-5