6-20
YES
OK
YES
YES
NO
NO
NO
Is genuine
hydraulic oil or
equivalent being
used?
Is not hydraulic
oil temperature
high?
Does the symptom
change when port
relief valve is
replaced with
normal value?
BOOM, ARM OR BUCKET CYLINDER EXTENDS OR CONTRACTS ITSELF AND ATTACHMENT FALLS
3)
Normal
Port relief valve is
faulty.
刔
Control valve's
return spring is
faulty.
Pressure
tightness
between control
valve casing and
spool is poor.
Contact surface
between poppet
and seat is poor.
Cylinder is faulty.
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.
刔
Is cylinder
internal leakage
within standard
level?
Abnormal
Abnormally high.
Is control valve
return spring
normal?
Disassemble and
inspect load
check valve in
MCV and check
for any fault.
Cause
Remedy
YES
NO
Summary of Contents for HX140L
Page 12: ...SECTION 1 GENERAL SECTION 1 GENERAL Group 1 Safety Hints 1 1 Group 2 Specifications 1 10...
Page 209: ...4 5 MEMORANDUM...
Page 694: ...8 68 125LCR8TM30 Turn casing 1 upside down and remove oil seal 3 using jig 29...
Page 734: ...8 108 Assemble plug 2 Plug NPT1 16 11 EA 17 21078TM68 21078TM69 21078TM70 21078TM71...
Page 756: ...8 130 Remove lock nut 22 and then boot 23 14 36078RL14 2507ARL10...