SUPPRESSION AR 5087631 - Caterpillar

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257B2 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)
Illustration 15 g01060470
(7) Gear pump (10) Control manifold for the high flow auxiliary circuitThe 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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(12) Switch for the auxiliary hydraulic circuitNote: 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.
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,