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| Illustration 1 | g01058163 |
247B Multi Terrain Loader Work Tool Hydraulic System (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (7) Control Valve (work tool) (8) Return Manifold Group (9) Ball Valve (10) Pilot Valve (work tool) (11) Relief Valve (charge oil) | |
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| Illustration 2 | g01058169 |
257B Multi Terrain Loader Work Tool Hydraulic System (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (7) Control Valve (work tool) (8) Return Manifold Gp (9) Ball Valve (10) Pilot Valve (work tool) (11) Relief Valve (charge oil) (12) Quick disconnects for the high flow auxiliary circuit (13) Control manifold for the high flow auxiliary circuit | |
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| Illustration 3 | g01058996 |
247B Multi Terrain Loader (3) Hydraulic Tank Group (6) Gear Pump (7) Control Valve (work tool) | |
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| Illustration 4 | g01058155 |
257B Multi Terrain Loader (3) Hydraulic Tank Group (6) Gear Pump (7) Control Valve (work tool) | |
Gear pump (6) supplies the work tool hydraulic system with oil. Pump (6) is mounted to the front end of the piston pump for the hydrostatic system. Pump (6) is splined to the drive shaft of the piston pump for the hydrostatic system. The piston pump for the hydrostatic system is mounted to the engine. When the engine speed increases, the speed of pump (6) increases. This causes pump (6) to pump more oil to the work tool hydraulic system.
The first section of gear pump (6) continuously pumps oil through control valve (7) . Control valve (7) is an open center control valve. The oil pressure for control valve (7) is regulated by a main relief valve that is installed in control valve (7) . The main relief valve is set to a pressure of 23000 ± 700 kPa (3335 ± 100 psi).
The pilot oil for the work tool hydraulic system is supplied by the second section of pump (6) . Oil flows out of the second section of pump (6) to the motor for the air conditioner. From the motor for the air conditioner, the oil flows to the fan drive motor. The oil flows through the fan drive motor to the oil filter. From the oil filter, the oil flows to the front section of the piston pump for the hydrostatic system. At the piston pump, the hydraulic oil flows passed the speed sensing valve. In order for the oil to flow to pilot valve (10) , all three of the interlocks must be disengaged. In order for oil to flow to pilot valve (10) , the hydraulic enable solenoid must be energized.
When the electrical requirements are complete, pilot oil will flow through a check valve to the accumulator (2) . The pilot oil is used to charge the accumulator (2) . The pilot oil will also flow to the pilot valve (10) . When pilot valve (10) is activated, oil will be directed to control valve (7) in order to shift a control spool to the desired position. Once a control spool shifts, high pressure oil from pump (6) will flow to the selected work tool. Relief valve (11) maintains the pressure for the pilot oil system at 3300 ± 200 kPa (480 ± 30 psi) at engine high idle. The engine high idle speed is 3240 ± 50 rpm. Refer to the Systems Operation, "Pilot Hydraulic System" for additional information.
Hydraulic System for the Lift Arms Without the Diverter Valve (If Equipped)
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| Illustration 5 | g01058242 |
247B Multi Terrain Loader work tool hydraulic system (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (charge oil, work tool, air conditioner and fan drive) (7) Control Valve (work tool) (8) Return Manifold Gp (9) Ball Valve (10) Pilot Valve (work tool) (11) Relief Valve (charge oil) | |
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| Illustration 6 | g01058243 |
257B Multi Terrain Loader work tool hydraulic system with the 228-9218 Diverter Valve (WORK TOOL POSITIONER) (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (charge oil, work tool, air conditioner and fan drive) (7) Control Valve (work tool) (8) Return Manifold Gp (9) Ball Valve (10) Pilot Valve (work tool) (11) Relief Valve (charge oil) (12) Quick disconnects for the high flow auxiliary circuit (13) Control manifold for the high flow auxiliary circuit | |
When the control lever for the work tool is moved to the RAISE position, pilot oil flows to the left side of the lift spool that is part of the control valve (7) . The pilot oil causes the lift spool to shift to the right.
Hydraulic oil flows from gear pump (6) into control valve (7) . The oil then flows past the lift spool and into the line for the head end of the lift cylinders (5) .
As oil forces the rods of the lift cylinders to extend, oil is forced out of the rod end of the cylinders. The oil that flows from the rod ends of the cylinders flows to the lift spool. The oil then flows to the tilt spool that is part of control valve (7) .
When the control lever for the work tool is moved to the LOWER position, pilot oil flows to the right side of the lift spool that is part of control valve (7) . The pilot oil causes the lift spool to shift to the left. Hydraulic oil flows from gear pump (6) through the spool and into the line for the rod end of the lift cylinders.
As oil forces the rods to retract, the oil is forced out of the head end of the cylinders. The oil flows to the lift spool. The oil then flows to the tilt spool that is part of control valve (7) .
When the control lever for the work tool is moved to the FLOAT position, pilot oil flows to the right side of the lift spool that is part of control valve (7) . The pilot oil causes the lift spool to shift fully to the left. With the spool in this position, the spool opens the rod ends of both of the lift cylinders and the head ends of both of the lift cylinders to the hydraulic tank (3) . The weight of the work tool will cause the work tool to lower to the ground. The work tool will then follow the contour of the ground. Supply oil from the gear pump will continue to flow into control valve (7) . The tilt spool may be operated when the lift spool is in the FLOAT position.
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| Illustration 7 | g01058244 |
In the event of engine failure, the ball valve (9) is used in order to manually lower the lift arms. Ball valve (9) allows oil to drain out of the head end of the lift cylinders. The hydraulic oil flow is directed to manifold (8) .
Hydraulic System for the Lift Arms with the Diverter Valve (If Equipped)
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| Illustration 8 | g01676769 |
247B Multi Terrain Loader work tool hydraulic system (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (7) Control Valve (work tool) (8) Return Manifold Gp (9) Ball Valve (10) Diverter Valve (11) Pilot Valve (work tool) | |
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| Illustration 9 | g01676779 |
257B Multi Terrain Loader work tool hydraulic system (1) Quick disconnects for the auxiliary circuit (2) Accumulator (3) Hydraulic Tank Group (4) Tilt Cylinder Group (5) Lift Cylinders (6) Gear Pump (7) Control Valve (work tool) (8) Return Manifold Gp (9) Ball Valve (10) Diverter Valve (11) Pilot Valve (work tool) (12) Quick disconnects for the high flow auxiliary circuit (13) Control manifold for the high flow auxiliary circuit | |
When the pilot valve (11) is moved to the RAISE position, the lift spool in control valve (7) is shifted to the RAISE position by pilot oil. Hydraulic oil flows from the gear pump (6) through the lift spool and into the line for the head end of the lift cylinders (4) . The oil from the rod end of the lift cylinders flows to the diverter valve (10) . The pressure from the rod end of the lift cylinders is balanced with the pressure from the head end of the tilt cylinders. This causes the work tool to remain level while the lift arms are raised. From the diverter valve, the oil flows to the lift spool. The oil then flows to the tilt spool.
The diverter valve only affects the RAISE function. The LOWER function is not affected by the diverter valve.
In the LOWER position, oil flows from the spool to the diverter valve. From the diverter valve, the oil flows to the rod end of the cylinders. The oil pushes on the piston. The cylinders retract. Oil from the head end of the cylinders flows to the lift spool. Then, the oil flows to the tilt spool.
For information on the operation of the diverter valve, refer to the Systems Operation, "Diverter Valve".
The ball valve (9) is used for manual lowering of the lift arms. The ball valve allows oil to drain out of the head end of the lift cylinders. The hydraulic oil flow is directed to the return manifold (8) . The ball valve should be used to lower the lift arms when the engine fails.
Tilt and Auxiliary Hydraulic Circuits
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| Illustration 10 | g01058542 |
247 Multi Terrain Loader hydraulic schematic (1) Auxiliary couplings (2) Hydraulic tank (3) Tilt cylinders (4) Lift cylinders (5) Control valve ( work tool) (6) Return manifold (7) Gear pump (8) Ball valve ( manual work tool lowering) (9) Pilot valve ( work tool) | |
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| Illustration 11 | g01058544 |
257 Multi Terrain Loader hydraulic schematic (1) Auxiliary couplings (2) Hydraulic tank (3) Tilt cylinders (4) Lift cylinders (5) Control valve ( work tool) (6) Return manifold (7) Gear pump (8) Ball valve ( manual work tool lowering) (9) Pilot valve ( work tool) (A) Couplings for circuit "A2" (B) Couplings for circuit "A2" (C) Solenoid for circuit "A2" (D) Solenoid for circuit "A1" (E) Check valve (F) Solenoid valve group (High flow boost) (G) Solenoid valve group (Auxiliary Flow) | |
The hydraulic oil is directed to the tilt spool in the control valve (5) by the pilot valve (9) . The end of the spool that receives the pilot oil depends on the position of the pilot valve (9) .
As the spool is shifted, hydraulic oil flows through the tilt spool and into both of the tilt cylinders.
If the machine is equipped with a diverter valve, the tilt cylinders will also be connected to the diverter valve. The diverter valve acts as a load leveler. The diverter valve is used only when the lift cylinders are being raised.
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| Illustration 12 | g01058869 |
(10) Switch for the auxiliary hydraulic circuit | |
In order for the auxiliary circuit to activate, you must press the right side of switch (10) . The ECM for the auxiliary hydraulic circuit activates solenoid (C) and solenoid (D) on the auxiliary spool. Solenoid (F) and solenoid (G) are not energized.
Most of the oil from the third section of pump (7) flows through solenoid (G) to the tank. Some of the oil flows through solenoid (F) to check valve (E) . Because most of the oil flows to the tank, the check valve does not open.
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| Illustration 13 | g01058859 |
Pilot oil is directed to the auxiliary circuit spool that is located in the control valve (5) by thumb wheel (11) . Roll thumb wheel (11) upward in order to increase the flow of oil to coupling (B) . Pilot oil moves the spool upward in order to allow more oil to flow through the spool to coupling (B) .
Roll the thumb wheel downward in order to increase the flow of hydraulic oil to coupling (A) . Pilot oil moves the spool downward in order to allow more oil to flow through the spool to coupling (A) .
For more information on the operation of the tilt and auxiliary hydraulic system, refer to the Systems Operation, "Control Valve (Work Tool)".
High Flow Auxiliary Circuit
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| Illustration 14 | g01060471 |
257 Multi Terrain Loader hydraulic schematic (1) Auxiliary couplings (2) Hydraulic tank (3) Tilt cylinders (4) Lift cylinders (5) Control valve ( work tool) (6) Return manifold (7) Gear pump (8) Ball valve ( manual work tool lowering) (9) Pilot valve ( work tool) (A) Couplings for circuit "A2" (B) Couplings for circuit "A1" (C) Solenoid for circuit "A2" (D) Solenoid for circuit "A1" (E) Check valve (F) Check valve (G) Solenoid valve group (High flow boost) (H) Solenoid valve group (Auxiliary Flow) | |
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| Illustration 15 | g01060470 |
(7) Gear pump (10) Control manifold for the high flow auxiliary circuit | |
The high flow system uses the second section and the third section of gear pump (7) . Gear pump (7) pumps oil to the control manifold for the high flow auxiliary circuit (10) . Also, the gear pump pumps oil to the control valve (work tool) (5) . The control manifold for the high flow auxiliary circuit (6) is located under the floorplate at the front of the machine.
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| Illustration 16 | g01060469 |
(12) Switch for the auxiliary hydraulic circuit | |
Note: The high flow auxiliary circuit will not activate if the machine is in rabbit mode with the two speed selector.
In order for the high flow auxiliary circuit to activate, you must press the left side of switch (12) . When you press switch (12) , the ECM for the auxiliary hydraulic circuit activates solenoid (H) . Solenoid (H) moves down. This stops the flow of oil to tank (2) . Solenoid (G) moves to the right. Oil flows through solenoid (G) to check valve (F) . The flow of oil opens the check valve. Solenoid (C) and solenoid (D) are activated.
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| Illustration 17 | g01060474 |
Oil for coupling (1) starts in oil tank (2) . The oil flows from the tank to gear pump (7) . The third section of gear pump (7) pumps the oil to the control manifold (10) for the high flow auxiliary circuit. The second section of gear pump (7) pumps oil to control valve (5) .
Pilot oil is directed to the auxiliary circuit spool that is located in the control valve (5) by thumb wheel (13) . Roll thumb wheel (13) upward in order to increase the flow of oil to coupling (B) "A1". Pilot oil flows through solenoid (D) to the spool. The spool moves upward in order to allow more oil to flow through the spool to coupling (B) .
Roll the thumb wheel downward in order to increase the flow of hydraulic oil to coupling (A) "A2". Pilot oil flows through solenoid (C) to the spool. The spool moves the spool downward in order to allow more oil to flow through the spool to coupling (A) .
At the same time, oil from the third section of pump (7) flows to manifold (10) . Solenoid (H) blocks the flow of oil to the tank. Check valve (E) blocks the flow of the oil. Some of the oil flows through solenoid (G) . This oil opens check valve (F) . Most of the oil from the third section of pump (7) flows through check valve (F) toward coupling (A) .
The oil from the second section and the third section of pump (7) combine at coupling (A) . This oil flows to the work tool. The oil returns through coupling (B) . The oil flows through spool (11) to the tank.
The high flow auxiliary circuit only flows from coupling (A) "A2", to coupling (B) "A1".
Secondary Auxiliary Circuit
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| Illustration 18 | g01058723 |
257 Multi Terrain Loader hydraulic schematic (1) "C+" coupling for the high flow auxiliary circuit (2) "C-" coupling for the high flow auxiliary circuit (3) Oil drain coupling for the high flow auxiliary circuit (4) Hydraulic tank (5) Tilt cylinders (6) Control manifold for the high flow auxiliary circuit (7) Solenoid Valve Group (High Flow) (8) Check Valve (9) Solenoid Valve Group (High Flow Boost) (10) Solenoid Valve Group (Auxiliary Flow) (11) Lift cylinders (12) Gear pump (13) Control valve ( work tool) (14) Return manifold (15) Ball valve ( manual work tool lowering) (16) Pilot valve ( work tool) | |
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| Illustration 19 | g01060490 |
(6) Control manifold for the high flow auxiliary circuit (12) Gear pump | |
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| Illustration 20 | g01060497 |
In order for you to use the secondary auxiliary circuit, you must press the right side of switch (17) . The ECM for the auxiliary hydraulic circuit activates solenoid (10) and solenoid (7) . Solenoid (10) moves down. This stops the flow of oil to the tank (4) . Solenoid (9) moves to the right.
The secondary auxiliary flow system uses the third section of gear pump (12) . Gear pump (12) pumps oil to the control manifold for the high flow auxiliary circuit (12) . Also, the gear pump pumps oil to the control valve (work tool) (5) . The control manifold for the high flow auxiliary circuit (6) is located under the floorplate at the front of the machine.
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| Illustration 21 | g01060492 |
In order for hydraulic oil to flow to fitting (1) "C+", you must press button (18) . Solenoid (7) moves to the right. Oil from the pump (12) flows through manifold (6) . Some of the oil flows through solenoid (9) to check valve (8) . The oil unseats check valve (8) . The oil flows through check valve (8) . The oil flows through solenoid (7) to coupling (1) .
The oil returns through both coupling (2) , "C-", and through line (3) . The oil in line (2) flows to solenoid (7) . Then, the oil flows to the tank. The oil in line (3) flows directly to the tank.
In order for hydraulic oil to flow to fitting (2) "C-", you must press button (19) . Solenoid (7) moves to the left. Oil from the pump (12) flows through manifold (6) . Some of the oil flows through solenoid (9) to check valve (8) . The oil unseats check valve (8) . The oil flows through check valve (8) . The oil flows through solenoid (7) to coupling (2) .
The oil returns through both coupling (1) , "C+", and through line (3) . The oil in line (1) flows to solenoid (7) . Then, the oil flows to the tank. The oil in line (3) flows directly to the tank.