Daewoo Solar S220LC-3 Excavator Service Manual

How to Use The Guide Manual

This manual provides information for servicing the Excavator. All service procedures are broken down into detailed steps, listed in their recommended sequence. The manual uses both photographs and drawings to help locate and itemize components. The table of Contents on the preceding pages is your best tool for finding the service procedure you need. Be certain to observe all Safety information included in these pages.

A schematic of each of the major engine systems is provided at the beginning of the section of the manual devoted to troubleshooting and repairing that particular system.

Basic safety precautions are list in the Safety section of the Service Manual. Additional safety precautions are list in the Safety section of the owner/operation/maintenance publication. Specific safety warnings for all these publications are provided in the description of operations where hazards exist. WARNING labels have also been put on the product to provide instructions and to identify specific hazards.

Pump Flow Control Regulator
Summary of Operation (refer to Figure 3-215)

1. The pilot piston (1) inside the smallest diameter regulator spool senses and reacts to changes in pilot pump discharge pressure (Pi).
2. Whenever pilot pressure (Pi) increases, to partially or fully overcome the tension of the return spring (2), the pilot piston (1) shifts to the right (as seen in the view in Figure 3-237) and the feedback control lever (3) rotates in a counterclockwise direction.
3. The feedback lever assembly (4) is connected to the control lever (3) and pivots clockwise (as seen in Figure 3-237), as the pilot piston (1) moves to the right. Movement of the pilot piston (1) and feedback lever assembly (4) allows pilot pressure oil into the wider diameter servo piston (5) chamber (in the uppermost spool of the regulator).
4. As the servo piston (5) moves to the right, clockwise rotation of the feedback lever assembly (4) causes movement of the pump swash plate tilting pin (6), attached to the lower end of the feedback lever (4). The operating angle of the main pump swash plate decreases, reducing pump output flow.
5. When the EPOS operating system has been switched to Power Mode Ill, electric signals from the EPOS controller to the main
electronic proportional control valve (7) will cause power shift pressure (Pf) through the valve to change, in direct proportion to the lectric signal. When power shift pressure (Pf) increases, pressure acts on the power shift piston (8).
6. When the power shift piston (8) shifts to the left, the control lever (3) on the side of the feedback lever assembly (4) rotates
clockwise, causing the feedback lever
assembly to pivot counterclockwise. The pilot piston (1) moves to the left and this
movement causes oil pressure in the wider diameter upper servo spool to release to the reservoir. As the servo piston (5) moves toward the left, pushing the feedback lever assembly (4) and tilting pin of the swash plate (6) (at the lower end of the lever assembly), pump output flow increases.