SHIELD AS 4490789 - Caterpillar

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(1) Hydraulic Tank (2) Joystick Controls (3) Swing Pedal (Swing Right, Swing Left) (4) Pilot Swing Valve (5) Delimber Control Valve (6) Pilot Shutoff Manifold (7) Swivel (8) Main Control Valve (9) Stabilizer Control Valve (10) Pilot Diverter Valve (11) Main Hydraulic Pump (12) Pilot Gear Pump
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(13) Hydraulic Return Oil Filter (14) Pilot Oil Filter (15) Case Drain Oil Filter (16) Hydraulic Refill Pump and Motor
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(17) Hydraulic Oil Cooler (18) Thermal Bypass Valve (19) Swing Motor (20) Swing Brake
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Hydraulic Lockout Control (21) Hydraulic Lockout Switch
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View of the eight button control panel on the dash. (22) Pilot Enable ButtonThe main hydraulic system consists of two variable displacement pumps (11) connected in tandem and an open center multicontrol valve (8). The main system also consists of a pressurized oil reservoir (1), oil cooler (17), and components to control the flow and condition of the oil. The main hydraulic system controls the cylinders, rotator, swing motor, and the stabilizers. For more information concerning the main hydraulic system, refer to Systems Operation, "Main Hydraulic System".The pilot hydraulic system is powered by a separate gear-type pilot pump (12). The pump is bolted to the outer end of main hydraulic pump (11). The pilot system also contains pilot shutoff manifold (6), pilot diverter valve (10), and thermal bypass valve (18). The pilot system controls flow to swing priority valve (4), and the main, stick, and swing controllers (2). In order for the pilot system to operate, the left armrest must be in the LOWERED position (21). Then pilot enable button (22) on the control panel must be activated (green light Off), which sends a signal to the pilot shut-off valve. When the left armrest is LOWERED and the pilot reset button is activated, the pilot shut-off valve is open, and the pilot system is pressurized. For more information concerning the pilot hydraulic system, refer to Systems Operation, "Pilot Hydraulic System"The swing system uses main control valve (8), pilot swing valve (4), swing motor (19), and the spring-applied swing parking brake (20). Swing pilot supply oil pressurizes pilot swing valve (4) giving priority to SWING whenever STICK UP and SWING are activated at the same time. The swing parking brake (20) is released whenever the left-hand armrest is lowered and the pilot enable switch is activated. For more information concerning the swing system, refer to Systems Operation, "Swing System".The stabilizer system uses main hydraulic pump (11), main control valve (8), and pilot shut-off manifold (6). The stabilizer system also contains hydraulic swivel (7), the electro-hydraulic stabilizer control valve (9) and the stabilizer cylinders. For more information concerning the stabilizer hydraulic system, refer to Systems Operation, "Stabilizer System".