Hyundai r35z-7 Workshop Manual page 203

3)
BOOM, ARM OR BUCKET CYLINDER EXTENDS OR CONTRACTS ITSELF AND
ATTACHMENT FALLS
Is not hydraulic
YES
oil temperature
high?
Is genuine
hydraulic oil or
equivalent being
used?
NO
Is cylinder internal
leakage within
standard level?
Does the symptom
change when port
Normal
relief valve is
replaced with
normal valve?
NO
Abnormally high.
Disassemble and
inspect check
YES
valve in hydraulic
circuit and check
for any fault.
NO
5-20
YES
Port relief valve is
faulty.
YES
Is control valve
return spring
normal?
Control valve's
NO
return spring is
faulty.
OK
Pressure
tightness
between control
valve casing and
spool is poor.
Abnormal Contact surface
between poppet
and seat is poor.
Cylinder is faulty.
Cause Remedy
Disassemble
and repair or
replace.
Disassemble
and replace.
Locate the cause
of hydraulic oil
temperature rise
and lower it to
proper level.
Replace with
genuine
hydraulic oil or
equivalent.
Disassemble
and repair.
Disassemble
and repair.
Disassemble
and repair.