YES
6-9
4. SWING SYSTEM
BOTH LH AND RH SWING ACTIONS ARE IMPOSSIBLE
1)
Are attachment
and travel
motions
impossible at all?
Does safety
solenoid valve
operation
normal?
NO
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
YES
Is gear pump pilot
pressure within
standard level?
Is MCV swing
pilot pressure
within standard
level?
Is swing parking
brake release
valve faulty?
Are broken pieces
of coupling present
when dust plug
under engine fly
wheel is removed?
Does not symptom
change when A1
and A2 pump
discharge hoses
are exchanged?
Is oil in hydraulic
tank within
standard level?
Is RH travel
function normal?
Safety solenoid
valve faulty or not
operated.
Gear pump faulty.
Pump connection
coupling is broken.
Hydraulic pump is
out of order.
Swing control valve
spool is stuck.
Hydraulic pump is
broken.
Swing parking
brake release valve
is broken.
Swing reduction
unit is broken.
Swing motor is
broken.
Pilot relief valve in
gear pump is faulty.
Gear pump is out of
order.
RCV is broken.
Replenish
specified oil to the
standard level.
Repair or replace.
Repair or replace.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair.
Disassemble and
repair or replace.
Disassemble and
repair.
Clean pilot piping
interior or repair
piping.
Disassemble and
repair.
ͽ
;
Ϳ
ͽ
Is main relief
valve faulty?
Does swing
control valve
spool move?
Does swing
motor rotate?
Is gear pump
delivering oil?
Is there oil
leakage from
pilot piping or is it
clogged?
;
Ϳ
Is gear pump pilot
pressure within
standard level?
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
YES
See Note 1
See Note 1
See Note 2
See Note 5
Cause
Remedy