GUIDE-VALVE 3890692 - Caterpillar

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Pilot hydraulic system (1) Pilot control actuators (2) Solenoid valve (hydraulic lockout) (3) Check valve (4) Pressure switch (filter bypass) (5) Filter bypass (6) Pressure sensor (7) Pilot/axle oil cooler pump (8) Pilot filter (9) Pressure reducing valve (10) Pilot accumulator (11) Hydraulic tank (A) Implement supply oil
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Hydraulic tank (top view) (11) Hydraulic tank (12) Filler cap
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Hydraulic tank (front view) (8) Pilot filter (13) Breaker relief valveHydraulic tank (11) is beneath the access door behind the cab. Add oil by removing filler cap (12). Breaker relief valve (13) is used in order to relieve excessive pressure or vacuum from hydraulic tank (11). Hydraulic tank (11) also has nine filters and a sight gauge for checking the oil level.
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Pilot/axle oil cooler pump (top view) (7) Pilot/axle oil cooler pump (14) Pump driveThe pump compartment is beneath the access doors in the platform behind the cab. Pilot pump (7) is a variable displacement piston pump that is mounted on the rear of the pump drive on the right side of the machine. The pilot pump provides pilot oil to the implement system.
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Pilot filter (4) Filter bypass switchThe oil that is provided by the pilot pump flows through pilot filter (8). Pilot filter (8) is equipped with a bypass valve in the filter mounting base. When the filter is plugged, the filter bypass valve opens and oil flows over the check valve. Then, switch (4) opens and the VIMS main module will activate an alert indicator in the cab so that the operator is aware of the problem.
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(9) Pressure reducing valvePressure reducing valve (9) is fastened to the inside of the pump compartment on the right side of the machine. Pilot oil from the pilot filter flows to the pressure reducing valve. The pressure reducing valve maintains the pressure in the pilot hydraulic system at 3450 kPa (500 psi).
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Main control valve (1) Pilot control actuatorsPilot control actuators (1) control the flow of pilot oil from the spools in the main control valve back to the hydraulic tank. As current from the implement electronic control module (ECM) is applied to one pilot control actuator, the actuator will begin to shift. Trapped oil from behind the stem in the main control valve will begin to drain pilot oil from the actuator. The spring force on the opposite side of the stem will shift the stem. The movement of the stem is proportional to the current that is applied to the pilot control actuator. Oil that is supplied from the implement pumps to the main control valves will flow to the respective cylinder. As the current to the actuator is removed, the actuator shifts back to the relaxed position. Then, the oil is trapped between the stem and the actuator. The combination of the oil pressure and the spring force to each end of the stem is equalized.