OM3050 7/09 Operating Instructions - Section 30 Page 30-25 DISABLED TRUCK DUMPING PROCEDURE Raising the Body Sometimes it is necessary to dump a load from the body of a truck when the hoist system is inoperable. To use this feature, two hoses (supply and return) must be connected to a hydraulic source (such as an operational truck or an auxiliary power unit). 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: Quick disconnect fittings (3 & 4, Figure 30-6) are pro- vided on the overcenter valve to allow operation of the hoist circuit for temporary truck operation if the hoist pump, hoist valve or other hoist system compo- nent is not operational. This will allow maintenance personnel to raise the truck body to dump the load before moving the disabled truck. a.
Stop the engine and wait two minutes to allow the hydraulic system pressure to bleed down. In the example, Figure 30-6 illustrates a typical hookup from the good truck. The disabled truck may be another Model 860E, or a different Komatsu electric drive truck model. b. Remove the cap from the hoist pilot valve relief valve 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. Hookup Ensure that there is an adequate, clear area to dump the loaded body. When the good truck is in position, shut down the engine and allow the hydraulic system to bleed down.
Ensure 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 30-6) to the power down circuit of the disabled truck. The hose must be rated to withstand 17 000 kPa (2,500 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. FIGURE 30-6. PUMP MODULE, HOSE HOOKUP NOTE:
If both trucks are the same model, the hoses will be installed at the quick disconnects shown in Figure 30-6 and will be crossed when connected. 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