Disabled Truck Dumping Procedure - Komatsu 830E-AC Shop Manual

DISABLED TRUCK DUMPING
PROCEDURE
Sometimes it is necessary to dump a load from the
body of a truck when the hoist system is inoperable.
The following instructions describe the use of a
"good" truck to provide the hydraulic power required
to raise the body of the "disabled" truck to dump the
load.
In the example below, Figure 30-1 illustrates a typical
hookup from the good truck. The disabled truck may
be another Model 830E or a different Komatsu
model.
Hookup
Ensure there is an adequate, clear area to dump the
loaded body. When the good truck is in position, stop
the engine and allow the hydraulic system to bleed
down. Ensure pressure has bled off before connect-
ing hoses.
1. With the good truck parked as close as possible
to the disabled truck, attach a hose from the
power up quick disconnect (3, Figure 30-1) to
the power down circuit of the disabled truck.
The hose must be rated to withstand 17 237
kPa (2500 psi) or greater pressure.
NOTE: The power down circuit will use a smaller
diameter hose (tube) than the power up circuit.
2. Connect another hose from power down quick
disconnect (4) to the power up circuit of the dis-
abled truck.
NOTE: If both trucks are a model 830E, the hoses
will be installed at the quick disconnects shown in
Figure 30-1 and will be crossed when connected.
Raising the Body
3. On the disabled truck, move the hoist control
lever to POWER UP and then release it to place
the hoist pilot valve in the HOLD position. Leave
in this position during entire procedure.
4. Start the engine on the good truck. Place the
hoist control in the POWER DOWN position and
increase engine rpm to high idle to dump the
disabled truck. If the body of the disabled truck
fails to raise, increase the good truck power
down relief pressure as follows:
a. Stop the engine and allow the hydraulic sys-
tem to bleed down.
A3-34
Lowering the Body
FIGURE 30-1. PUMP MODULE, HOSE HOOKUP
General Safety and Operating Instructions
b. Remove the cap from the hoist pilot valve
relief valve located in the hydraulics compo-
nents cabinet behind the cab. While counting
the number of turns, slowly screw relief valve
adjustment screw clockwise until it bottoms.
5. Repeat Step 4 to dump the disabled truck.
6. Place the hoist lever of the good truck in FLOAT
to lower the body. If necessary, momentarily
place the hoist control in POWER UP until the
body is able to descend in FLOAT. Do not
accelerate the engine.
7. After the body is lowered, stop the engine.
Bleed the hydraulic system of pressure and dis-
connect the hoses.
8. Reduce power down relief valve pressure to
normal on the good truck by turning the adjust-
ment counterclockwise the same number of
turns as required in Step 4 b.
9. Check power down relief pressure per instruc-
tions in the shop manual, Section L, Hydraulic
Check-Out Procedure.
10. Check the hydraulic tank oil level.
1. Hoist Valve
2. Overcenter Manifold
3. Power Up Quick Disconnect (Connect to power
down circuit of disabled truck.)
4. Power Down Quick Disconnect (Connect to power
up circuit of disabled truck.)
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