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| Illustration 1 | g01637449 |
Main hydraulic system (1) Tilt cylinder (3) Lift cylinders (5) Auxiliary hydraulic couplers (6) Main control valve (7) Test port (G) for implement pressure (8) Return oil filter (10) Cooler bypass valve (high pressure) (11) Oil cooler (12) Bypass valve (low pressure) (13) Solenoid valve for the work tool positioner (if equipped) (14) Hydraulic tank (A) Return line from the hand metering unit (B) Supply line from the steering priority valve (C) Line to case of the hydrostatic piston motor (D) Pilot supply line (E) Pilot line for DUMP (F) Pilot line for TILT BACK (G) Pilot line for RAISE (H) Pilot line for LOWER | |
The main hydraulic system includes the following components: tilt cylinder (1), lift cylinders (3), auxiliary hydraulic couplers (5), main control valve (6), return oil filter (8), cooler bypass valve (10), oil cooler (11), bypass valve (12) and hydraulic tank (14) .
The main hydraulic system is powered by the gear pump. The gear pump draws oil from the hydraulic tank (14). Oil flows from the gear pump to the steering priority valve in the hand metering unit. Refer to Systems Operation, "Steering System" for more information on the operation of the following components: gear pump, steering priority valve and hand metering unit.
The charge pump supplies pilot oil to the pilot valve. The pilot valve then provides oil pressure to the main control valve (6) in order to move the spools within each of the control valves. When the spools are moved, higher pressure oil that is provided by the gear pump flows into the main control valve. From the main control valve, the higher pressure oil flows to one or more of the following components: tilt cylinder (1), lift cylinders (3) and auxiliary hydraulic couplers (5). Refer to Systems Operation, "Pilot Hydraulic System" for more information on the operation of the following components: charge pump and pilot valve. Refer to Systems Operation, "Main Control Valve" for more information on the operation of the main control valve.
Return oil flows into the main control valve (6), through the oil cooler (11), through the return oil filter (8), through the bypass valve (12), and into the tank (14). The cooler bypass valve (10) allows higher pressure oil to flow around the oil cooler (11) .
Hydraulic Tank
The hydraulic tank is located on the right side of the machine below the cab.
The hydraulic tank (14) stores hydraulic oil. The hydraulic tank supplies oil for the following systems: hydrostatic system, steering system, pilot hydraulic system, main hydraulic system and quick coupler. The hydraulic tank is located on the right side of the machine.
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| Illustration 2 | g01146880 |
Hydraulic Tank (14) Hydraulic tank (15) Breather (16) Outlet to the gear pump (17) Outlet to the charge pump (18) Temperature sender (19) Return lines | |
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| Illustration 3 | g01146908 |
(15) Breather (20) Filler cap (21) Sight glass | |
The hydraulic tank (14) is located below the cab on the right side of the machine. A strainer is located in the hydraulic tank. The strainer is located in the outlet of the hydraulic tank. The outlet of the hydraulic tank leads to the outlet (16) to the gear pump and to the outlet (17) to the charge pump. The hydraulic tank is not pressurized. The breather (15) vents from the top of the hydraulic tank. The breather is located behind a panel on top of the hydraulic tank. The filler cap (20) is located on the front of the hydraulic tank. The sight glass (21) is located on the outside of the hydraulic tank.
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| Illustration 4 | g01149955 |
(22) Indicator light for excessive temperature | |
When the temperature of the hydraulic oil becomes excessive, a temperature sender (18) activates the indicator light (22) that is located on the dash.
Main Control Valve
The main control valve is located ahead of the hitch.
The pilot valve controls the main control valve (6). Refer to Systems Operation, "Pilot Hydraulic System" for information on the operation of the pilot valve. The main control valve is sometimes referred to as the implement control valve. The main control valve controls the following components: tilt cylinder (1), lift cylinder (3) and auxiliary hydraulics (5). Refer to Systems Operation, "Main Control Valve" for information on the operation of the main control valve.
Oil Cooler
The oil cooler is located at the rear of the machine inside the engine compartment.
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| Illustration 5 | g01147108 |
(11) Oil cooler | |
The oil flows from the outlet of the main control valve (6) to the oil cooler (11) and the cooler bypass valve (10). The oil cooler dissipates heat from the hydraulic system in order to prevent overheating.
Cooler Bypass Valve (High Pressure)
The cooler bypass valve is located on the left side of the machine ahead of the engine compartment.
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| Illustration 6 | g01147119 |
Cooler bypass valve (high pressure) (23) Inlet (24) Poppet (25) Spring (26) Outlet | |
The cooler bypass valve (10) allows higher pressure oil to flow around the oil cooler (11) and to the return oil filter (8). The higher pressure oil occurs when the oil is cold.
The oil flows into the inlet (23). When the oil pressure overcomes the force of spring (25), the poppet (24) moves to the right and the oil flows through the outlet (26) and to the return oil filter.
Return Oil Filter
The return oil filter is located on the left side of the machine beneath the cab.
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| Illustration 7 | g01163672 |
(8) Return oil filter | |
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| Illustration 8 | g01648373 |
Return oil filter (27) Bypass valve (28) Oil Filter (J) Return line from the hydraulic systems (K) Line to the bypass valve (low pressure) | |
Return oil flows to the return oil filter (8) from the following systems: steering system, main hydraulic system and quick coupler. The return oil filter contains the following components: bypass valve (27) and oil filter (28). During normal operation, oil flows through the oil filter (28). If the oil is cold or if the filter is plugged, the bypass valve (27) allows oil to flow around the filter.
Bypass Valve (Low Pressure)
The bypass valve is located below the hydrostatic piston pump.
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| Illustration 9 | g01147299 |
Bypass valve (low pressure) (29) Inlet (30) Poppet (31) Spring (32) Outlet | |
Oil flows from the return oil filter (8) to the bypass valve (12) and to the bearings in the hydrostatic piston motor (C). The bypass valve creates back pressure at the return oil filter. The back pressure causes oil to flow to the bearings in the hydrostatic piston motor. For more information on the operation of the hydrostatic piston motor, refer to Systems Operation, KENR7635, "Piston Motor (Hydrostatic)".
The oil flows into the inlet (29). When the oil pressure overcomes the force of spring (31), the poppet (30) moves to the right and the oil flows through the outlet (32) and to the hydraulic tank (14) .