Komatsu F30791, Shop Manual

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CONTROL AND REGULATION OF THE LS DIFFERENTIAL
PRESSURE AND ADJUSTMENT OF THE LS VALVE (PC20R-8)
20-44
TESTING AND ADJUSTMENTS
CONTROL AND REGULATION OF THE LS DIFFERENTIAL
PRESSURE AND ADJUSTMENT OF THE LS VALVE (PC20R-8)
Test
1. Test method with differential pressure gauge E3
1 - Remove the plugs (1) and (2), mount the elbow E5
and mount two pressure adapters.
2 - Connect the differential pressure gauge E4 .
H Connect the high-pressure side to the adapter
(2) and the low-pressure side to the adapter
(1).
3 - Start the engine and use the working equipment
to raise one track-shoe.
4 - Bring the engine up to high idling and check the
LS differential pressure according to the test con-
ditions in Table 1.
Table 1
Position of
the travel
lever
LS differential pressu-
re in bar (kg/cm
2
)
NOTES
Neutral
Max. 34.3
(Max. 35)
The LS differential pressure
is equal to the pressure gi-
ven by the unloading valve
Half the
stroke (Swing
without load)
2. Test method with pressure gauges E2 or E3
H The maximum differential pressure is 34.3 bar (35
kg/cm
2
). For a precise check use the same pres-
sure gauge together with a decimal scale.
1 - Remove the plugs (1) and (2) and mount two
pressure adapters.
2 - Connect pressure gauge E2 or E3 to the pres-
sure adapter (2).
3 - Start the engine and use the working equipment
to raise one track-shoe.
4 - Bring the engine up to high idling and measure
the delivery pressure of pump ( P
P
) in the condi-
tions shown in Table 1. Make a note of the values
read.
H Check the instrument by reading it from the
front and making sure that the reading is cor-
rect.
5 - Disconnect the pressure gauge E2 or E3 from the
pump delivery and connect it to the pressure
adapter (1).
6 - Measure the LS pressure in the same conditions
indicated at point 4. Make a note of the value read.
7 - Subtract the LS pressure from the delivery pres-
sure of the pump ( P
P
) in order to obtain the differ-
ential pressure value D P
LS
( P
P
± LS = D P
LS
)
H D P
LS
normal= 34.3 bar (35 kg/cm
2
)
PC20R-8 PC27R-8
RKPA2310
1
E
4
2
E
5
RKPA2320
1
E
3
2
RKPA2330
1
E
3
2