TESTING AND ADJUSTING HYDRAULIC PRESSURE
TESTING AND ADJUSTING
IN WORK EQUIPMENT, SWING, TRAVEL CIRCUIT
TESTING AND ADJUSTING
HYDRAULIC PRESSURE IN WORK
EQUIPMENT, SWING, TRAVEL
CIRCUIT
MEASURING
* Hydraulic oil temperature when measuring: 45 -
55°C
A Lower the work equipment to the ground and
stop the engine. Loosen the oil filler cap slowly
to release the pressure inside the hydraulic tank.
Then put the safety lock lever in the LOCK posi-
tion.
Remove pressure pick-up plug (1) or (2) (Thread
dia. = IOmm, Pitch = 1.25 mm) from the circuit to
be measured, then install oil pressure gauge CI
(58.8 MPa (600 kg/cm?).
Measuring main unload pressure
* Unload pressure when front and rear pump flows
are merged.
Measure the oil pressure in H/O mode with the
engine at high idling and the control levers at
neutral.
Measuring sub-unload pressure
* The unload pressure in the circuit which is not
under load when the front and rear pump flows
are divided.
1. Set to H/O mode + boom/swing priority selection
mode ON.
2. Measure the pressure in the pump circuit on the
opposite side when the arm or bucket circuit is
relieved.
Arm relief:
Load on front pump, rear pump
unloaded.
Bucket relief:
Load on rear pump, front pump
unloaded.
Measuring pump relief pressure
1. When LS relief valve is actuated
When hydraulic pressure is 31.9 MPa (325 kg/
cm?
1)
*
Measure the pressure when each actuator
except the travel actuator is relieved in H/O
mode with the engine at high idling.
Note that the set pressure of the safety valve
for the swing motor and head end of the boom
is lower that the LS relief pressure, so the valve
measured will be the relief pressure of the
safety valve.
If the swing lock switch is ON, the pressure will
rise, so always keep the lock switch OFF when
measuring.
XlOZZO24
Table 1
Combination of pumps and actuators
controlled when flow from front and
rear pump is divided.
Pump
Front pump
Controlled actuator
l Arm cylinder
0 Swing motor %
l L.H. travel motor
l Boom cylinder %
Rear pump
l Bucket cylnder
l R.H. travel motor
g The set pressure of the safety valve at the
head end and the swing motor is lower than
the set pressure of the main relief valve.
I
20-39
0
To Next Page
Loading...
Need help?
General
