Disabled Truck Dumping Procedure; Hookup; Raising The Body; Lowering The Body - Komatsu 930E-4SE Operation & Maintenance Manual

OM3062 8/11
DISABLED TRUCK DUMPING
PROCEDURE
Sometimes it is necessary to dump a load from the
body of a truck if 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 following example, Figure 30-4 illustrates a
typical hookup from the good truck. The disabled
truck may be the same truck model or a different
Komatsu truck model.

Hookup

Make sure that there is an adequate, clear area to
dump the loaded body. When the good truck is in
position, turn off the engine and allow the hydraulic
system to bleed down. Make sure that the pressure
has bled off before connecting the hoses.
1. With the good truck parked as close as possible
to the disabled truck, attach a hose from the
power up quick disconnect (4, Figure 30-4) to
the power down circuit of the disabled truck.
The hose must be rated to withstand 17,000
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 the power down
quick disconnect (3) to the power up circuit of
the disabled truck.
NOTE: If both trucks are the same model, the hoses
will be installed at the quick disconnects shown in
Figure 30-4 and will be crossed when connected.

Raising the Body

1. 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).
2. Start the engine on the good truck, place the
hoist control in the POWER DOWN position and
increase the 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. Shut down engine and allow the hydraulic
system to bleed down.
b. Remove the cap from the hoist pilot valve
relief valve (2), located in the hydraulics
components cabinet behind the cab. While
counting the number of turns, slowly turn the
relief valve adjustment screw clockwise until
it bottoms. Repeat Step 2.
Operating Instructions - Section 30

Lowering the Body

1. 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.
2. After the body is lowered, shut down the
engine, bleed the hydraulic system, and
disconnect the hoses.
3. Reduce the power down relief valve pressure
on the good truck to normal by turning the
adjustment counterclockwise the same number
of turns as required in Step 2b of "Raising the
Body."
4. Check the power down relief pressure. Refer to
Section L, Hydraulic Check-Out Procedure, in
the shop manual.
5. Check the hydraulic tank oil level.
FIGURE 30-4. PUMP MODULE, HOSE HOOKUP
1. Hoist Valve
2. Tubes to LH Hoist Cylinder
3. Power Down Quick Disconnect (Connect to power
up circuit of disabled truck.)
4. Power Up Quick Disconnect (Connect to power
down circuit of disabled truck.)
5. Overcenter Manifold
Page 30-21