Komatsu Utility PC12R-8 MISTRAL, Shop Manual

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20-39
TESTING AND ADJUSTMENTS
CONTROL AND REGULATION OF PRESSURE
IN THE HYDRAULIC CIRCUITS (PC12R)
Valve adjustment
H The unloading valve cannot be re-adjusted, only sub-
stituted.
1. Adjustment ofthe main reliefvalve
If the pressures measured for the working equipment
and machine travel do not fall within normal values,
adjust the main relief valve (1) as follows:
1 - Remove the lower casing (2).
2 - Loosen the lock nut (3) and rotate the adjusting
screw (4).
. To INCREASE pressure, turn in a CLOCKWI-
SE direction.
. To DECREASE pressure, turn in a COUN-
TER-CLOCKWISE direction.
H Each turn of the adjusting screw (4) varies the
pressure by about 125 bar (128 kg/cm
2
).
3 - Lock the nut (3).
Nut: 59 w 10 Nm
H After adjustment, check the adjustment of the
main relief valve with the same procedures as
used for the measurements.
2. Adjustment ofthe safety valve ofthe swing mo-
tor
If the pressures measured for the swings, to the right
and to the left, do not come within the normal values,
adjust the safety valve (1) of the swing motor as fol-
lows:
1 - Remove the cap nut (2).
2 - Loosen the lock nut (3) and turn the adjusting
screw (4).
.
To INCREASE pressure, turn in the CLOCK-
WISE direction.
.
To DECREASE pressure, turn in the COUN-
TER-CLOCKWISE direction.
3 - Lock the nut (3) and replace the cap nut (2).
H After the adjustments, check the setting of the sa-
fety valves following the same procedure used for
the measurements.
PC12R-8 PC15R-8
RKPA0290
2
RKP04830
1
3
4
RKPA0300
1
1
RKP04920
2 3
4