Manitowoc Grove YB5515 Service Manual

GROVE Published 10-21-2010, Control# 198-04 4-3
5540F/YB5515 SERVICE MANUAL HYDRAULIC SYSTEM
4
TROUBLESHOOTING GUIDES
Table 4-1
General Hydraulic System Troubleshooting
Problem Possible Cause Remedy
Noise (above normal). Air in system. With engine at low rpm, operate
all control functions several times
to return the air to atmosphere
through the tank breather.
Low oil supply. Add recommended oil.
Restriction in pump inlet line. Remove and clean inlet line to
pump.
Dirty oil. Change oil and filters. See
Preventative Maintenance, Chapter 5.
Loose clamps, vibration of hydraulic
lines.
Check and tighten.
Dirt or foreign material in a relief valve. Clean or replace the relief valve.
Broken control valve spool. Replace the control valve section.
Pump bearings worn. Replace the bearings or pump.
Slow operating speeds (All functions). Low engine rpm. Increase engine rpm.
Air leak in pump inlet line. Tighten pump inlet line. Replace O-ring
in inlet flange.
Air in oil (foam in tank). Check oil level, look for leaks in
the system.
Leakage in the load sense relief valve. Remove and clean or replace the
relief valve.
Improper load sense relief valve
setting.
Replace the relief valve.
Leakage in hydraulic swivel. Replace seals on swivel shaft.
Control valve not fully actuated. Check spool travel.
Improper primary pump. Check and adjust pump pressure
settings. See Main Control Valve.
Faulty pump. Overhaul or replace pump.
No movement when system is first
started.
Low oil level. Check and add oil.
Air or restriction in inlet line to pump
pressure.
Check and tighten inlet line. Clear
restriction.
Cold oil or wrong weight of oil. Use correct oil, follow normal
warming procedure.
Loss of movement during operation. Low oil level. Check and add oil.
Vacuum in hydraulic tank. Clean tank filler/breather cap.
Restriction or leakage in the relief
valve.
Clean or replace the relief valve.
Broken hydraulic line. Replace.
Bad seal in hydraulic swivel. Replace seals.
Broken gear or shaft in pump. Overhaul or replace.
Reference Only

Manitowoc Grove YB5515 Specifications

General

Brand	Manitowoc
Model	Grove YB5515
Category	Construction Equipment
Language	English