Komatsu PC130-7, Shop Manual

Page: 41 / 342

PC130-7
20-123
TESTING AND ADJUSTING
3. Measuring work equipment circuit relief pres-
sure
1) Start the engine and move the cylinder to be
measured to the stroke end.
2) Run the engine at high idling and relieve the
cylinder and measure the oil pressure.
a
The pressure measured when the main relief
valve is relieved is indicated.
a
If the one-touch power maximizing switch is
released, the main relief valve is relieved at
low pressure. If the former is pressed, the
latter is relieved at high pressure.
a
If the swing lock switch is set in the LOCK
position, the 2-stage relief solenoid valve is
turned ON and the main relief valve is
relieved at high pressure. Accordingly, keep
the swing lock switch turned OFF.
4. Measuring swing circuit relief pressure
1) Start the engine and set the swing lock
switch in the LOCK position.
2) Run the engine at high idling and relieve the
swing circuit and measure the oil pressure.
a
The pressure measured when the swing
motor safety valve is relieved is indicated.
a
The swing motor relief pressure is lower than
the main relief pressure.
5. Measuring travel circuit relief pressure
1) Start the engine and lock the travel mecha-
nism.
k
Set pin [2] between the sprocket and
track frame to lock the travel mecha-
nism securely.
2) Run the engine at high idling and relieve the
travel circuit and measure the oil pressure.
a
The pressure measured when the main relief
valve is relieved is indicated. The travel cir-
cuit is always relieved at high pressure.
ADJUSTING
a
The unload valve cannot be adjusted.
1. Adjusting main relief pressure (High pres-
sure setting side)
a
If the high relief pressure of the work equip-
ment circuit and travel circuit is abnormal,
adjust the high pressure setting side of main
relief valve (2) according to the following pro-
cedure.
a
The high relief pressure is the pressure
applied when the 2-stage relief solenoid
valve is turned ON and the pilot pressure is
applied to the selector port.
1) Disconnect pilot hose (3).
2) Fixing holder (4), loosen locknut (5).
3) Turn holder (4) to adjust the pressure.
a
If the holder is
•
turned to the right, the pressure
rises.
• turned to the left, the pressure low-
ers.
a
Quantity of adjustment per turn of holder:
Approx. 12.6 MPa {Approx. 128 kg/cm
2
}
4) Fixing holder (4), tighten locknut (5).
3
Locknut: 39.2 – 49 Nm {4 – 5 kgm}
5) Connect pilot hose (3).
TESTING AND ADJUSTING OIL PRESSURE IN WORK EQUIPMENT,
SWING, AND TRAVEL CIRCUITS
(1)