NO
NO
NO
6-10
SWING SPEED IS LOW
2)
Is the trouble in
one direction or
in both direction?
Clogged or oil
leak.
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
NO
YES
YES
NO
YES
NO
YES
Does swing spool
move?
Is pilot piping
clogged or is it
leaking oil?
Is MCV pilot
pressure within
standard level?
Is gear pump pilot
pressure within
standard level?
Is swing motor's
drain rate within
standard value?
YES
Is MCV pilot
pressure same
on LH and RH
sides?
Is Arm speed
within standard
value?
Swing port relief
valve is faulty.
Swing control valve
spool is stuck.
RCV or shuttle
valve is faulty.
ͽ
Swing spool is
stuck.
;
Ϳ
Swing motor is
broken.
RCV or shuttle
valve is faulty.
Pilot relief valve
in gear pump is
defective.
Gear pump is
broken.
Main relief valve
faulty.
Hydraulic pump
is broken.
Shuttle valve is
faulty.
Pilot relief valve
is faulty.
Gear pump is
faulty.
Disassemble and
repair or replace.
Disassemble
and repair.
Clean pilot piping
interior or repair
piping.
Disassemble
and repair.
Disassemble
and repair.
Disassemble
and repair.
Disassemble
and repair.
Clean pilot piping
interior or repair
piping.
Disassemble and
repair or replace.
Disassemble
and repair.
Main relief valve
pressure resetting
or repair.
Disassemble
and repair.
Repair or replace.
Repair or replace.
Repair or replace.
ͽ
;
Ϳ
Check that pilot
piping is clogged
or oil is leaking
from it?
Clogged or oil leak.
Is gear pump
delivering oil?
Does the symptom
change when A1
and A2 pump
discharge hoses
are exchanged?
Is gear pump
output pressure
within standard
level?
Is MCV pilot
pressure within
standard level?
Both directions
Single direction
Is main relief
valve setting
pressure normal?
YES
YES
Does swing spool
move?
See Note 2
See Note 2
See Note 5
See Note 1
See Note 7
See Note 2
See Note 1
Cause
Remedy