Operating Instructions - Section 30 03/13 OM3054 Page 30-18 Raising the Body 5. Move the hoist control lever on the disabled truck to the HOLD position. Leave the lever in this position during the entire procedure. Lowering the Body 9. After the load has been emptied from the body, release the hoist control lever. The body of the disabled truck should immediately begin floating downward. 6. Adjust the power down relief setting on the good truck to the maximum setting. The power down relief valve (1, Figure 30-7) is located on pilot valve (2) inside of the brake cabinet. Gen- tly, turn the adjustment screw clockwise until it bottoms out.
Count the exact number of turns that the adjustment screw is turned, and note for later adjustment. If any residual material left in the body prevents lowering, perform the following: a. Place the good truck hoist lever in the POWER UP position, and monitor the body of the disabled truck for downward move- ment. The body of the good truck may rise a small amount during this step. 7. Start the engine on the good truck, and adjust the engine speed to 1000 rpm. b. Once the body of the disabled truck begins downward, move the hoist control all the way forward. Then, release the lever to the FLOAT position. 8. Place the hoist control in the POWER DOWN position.
Continue to hold in this position until the hoist cylinders reach full extension. Increase engine speed as necessary. 10. Turn off the engine. Depressurize the brake accumulators, steering accumulators, and the hydraulic tanks on each truck. 11. Disconnect the hoses from each truck. DO NOT move the hoist control from the POWER DOWN position until full extension is reached. DO NOT attempt to move the lever to the HOLD position during this procedure. 12. Readjust the relief valve setting on the good truck. Turn the screw counter-clockwise the same number of turns as was noted earlier in this procedure. The power down relief valve set- ting is 10 342 kPa (1500 psi). FIGURE 30-7.
POWER DOWN RELIEF VALVE 1. Power Down Relief 2. Hoist Pilot Valve