Case L780 - Page 58

SECTION 4 - TROUBLESHOOTING
4-3
Problem Possible cause Action
System relief valve squeals Cold hydraulic oil. Let the hydraulic oil warm up to
working temperature.
Too heavy load in bucket. Material
weight exceeds loader’s specified
capacity.
Reduce the load in the bucket.
Relief valve set below specifica-
tion.
Contact your dealer.
Restriction in hydraulic hose, pipe
or quick release coupling.
Contact your dealer.
Insufficient lifting capacity Engine speed too low. Increase engine speed.
Too heavy load in bucket. Material
weight exceeds loader’s specified
capacity.
Reduce load.
Relief valve set below specifica-
tion.
Contact your dealer.
Pistons in lifting cylinders leak. Contact your dealer
Internal leakage in control valve. Contact your dealer.
Damaged hydraulic pump. Contact your dealer.
Loader drops with control valve
spool in “centering” position. Note:
The value at which the loader is
allowed to lower varies between
0.5--1.5 mm / min measured on
the piston rod, depending on load-
er model.
Pistons in lifting cylinders leak. Contact your dealer.
Internal leakage in control valve. Contact your dealer.
Control valve or cable system
binds and prevents valve spool
from returning to center position.
Find the reason for binding and
repair it.
Control valve spool(s) do not re-
turn to neutral position
Control valve centering spring is
damaged.
Contact your dealer.
Control valve spool binds in its
bore.
Contact your dealer.
Control lever or cable system
binds.
Find the reason for binding and
repair it.
External hydraulic oil leakage Loose hydraulic unions. T ighten loose unions.
Damaged hydraulic hoses, pipes,
couplings or O-rings in couplings.
Find the reason for the leakage
and change the damaged compo-
nent.
Damaged O-ring in control valve. Contact your dealer.
Control valve spool or housing
damaged and/or worn.
Contact your dealer.
Piston rod seal in cylinder leaks. Contact your dealer.