Hyundai HX130LCR Manual page 343

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 value?
NO
Abnormally high.
Disassemble and
inspect load
YES
check valve in
MCV and check
for any fault.
NO
6-20
YES
YES
Is control valve
return spring
normal?
NO
OK
Abnormal
Cause Remedy
Port relief valve is Disassemble
faulty. and repair or
replace.
ⓐ
Control valve's Disassemble
return spring is and replace.
faulty.
Locate the
cause of
hydraulic oil
temperature rise
and lower it to
proper level.
Replace with
genuine
hydraulic oil or
equivalent.
Pressure Disassemble
tightness and repair.
between control
valve casing and
spool is poor.
Contact surface Disassemble
between poppet and repair.
and seat is poor.
Cylinder is faulty. Disassemble
and repair.