Hyundai r35z-7 Workshop Manual page 193

2)
SWING SPEED IS LOW
Is MCV pilot
pressure same
on LH and RH
sides?
Single direction
Is the trouble in
one direction or
in both direction?
Both directions
Is dozer speed
within standard
value?
Is main relief valve
setting pressure
normal?
YES
Does swing control
YES
valve spool move
smoothly by hand?
NO
YES
Is not pilot piping
clogged or is not
NO
it leaking oil?
NO
YES
Is MCV pilot
YES
pressure within
standard level?
NO
NO
Is swing motor's
NO
drain rate within
standard value?
YES
Is gear pump pilot
pressure within
standard level?
NO
NO
YES
Is safety valve
pilot pressure
YES
within standard
level?
NO
5-10
Swing port relief
valve is faulty.
Swing control valve
spool is stuck.
Clogged or oil
leak.
Pilot valve or shuttle
valve is faulty.
Does swing
control valve
spool move
lightly by hand?
Swing control valve
spool is stuck.
Swing motor is
broken.
Check that pilot
piping is not
NO
clogged or oil is
Pilot valve or
not leaking from
shuttle valve is
it?
faulty.
Clogged or oil leak.
YES
Pilot relief valve
is defective.
Is gear pump
delivering oil?
Gear pump is
broken.
Main relief valve
faulty.
Does the YES
Hydraulic pump
symptom change
is broken.
when LH and RH
pilot hoses are
Shuttle valve is
exchanged?
faulty.
YES
Pilot relief valve
Is gear pump
is faulty.
output pressure
within standard
level?
Gear pump is
NO
faulty.
Cause Remedy
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.