Komatsu Galeo PC138US-8 Shop Manual page 360

SEN02458-01
5) Run the engine at high idle, operate the
left work equipment control lever to relieve
the arm circuit at the IN stroke end, and
test the oil pressure.
a Testing condition and method of judg-
ment: If the pressures are in the fol-
lowing ratio, the PC valve is normal.
Tested oil
pressure
Pump discharge
pressure
PC valve output
pressure
a If the PC valve or the servo piston is
abnormal, the PC valve output pres-
sure (servo piston inlet pressure) is
"the same as the pump discharge
pressure" or "almost 0".
6) After finishing test, remove the testing
tools and return the removed parts.
2. Testing PC-EPC valve output pressure
1) Open the side cover of the pump room
and remove oil pressure pickup plugs (3).
(3): PC-EPC valve output pressure pickup
plug
32
Operation of Ratio of oil
lever pressures
1
Arm IN relief
Approx. 0.6
(Approx. 3/5)
30 Testing and adjusting
2) Install nipples L2 and connect them to oil
pressure gauges [1].
a Use the oil pressure gauges of 5.9
MPa {60 kg/cm
3) Start the engine and set the working mode
in the power mode (P).
4) Run the engine at high idle and low idle,
set all the levers and pedals for work
equipment control, swing control, and
travel in neutral, and test the oil pressure
at each speed.
a Testing condition and method of judg-
ment: If the output pressures are in
the following ratio, the PC-EPC valve
is normal.
Operation of
Engine
lever
All control
Low idle
levers and
pedals in
High idle
neutral
5) After finishing test, remove the testing
tools and return the removed parts.
2
}.
Output pressure
Approx. 2.9 MPa
2
{Approx. 30 kg/cm }
Approx. 3.4 MPa
{Approx. 35 kg/cm 2 }
PC138US, USLC-8