FLANGE GP-EXHAUST 3843627 - Caterpillar

FLOAT Position
Control Valve In FLOAT Position
(1) Pump relief valve. (2) Inlet for pump oil. (3) Check valve. (4) Spring on valve spool. (5) Detent ball (four). (6) Passage to oil cooler for brakes and to the hydraulic tank. (7) Passage for rod ends of hoist cylinders. (8) Passage for head ends of hoist cylinders. (9) Valve spool. (A) RAISE position. (B) HOLD position. (C) FLOAT position. (D) LOWER position.The valve spool (9) is held in the FLOAT position (C) by four detent balls (5) in the detent groove around the end of the valve spool.The position of the valve spool in the FLOAT position (C) lets some of the pump oil flow through grooves in the valve spool and into passage (6) to the oil cooler, the brakes on the rear wheels, and then to the hydraulic tank. The grooves in the valve spool are restrictions and there is an increase in the pressure of the pump oil in the control valve.The pressure of the pump oil opens check valve (3) enough to let the pump oil flow through the check valve, through passage (7), through the rod ends of the hoist cylinders and into the second stage oil chambers. The weight of the dump body on the hoist cylinders pushes the oil from the head ends of the cylinders through passage (8) in the control valve. The oil flows from passage (8) into the hydraulic tank.Once the second stage cylinder is retracted, the weight of the dump body becomes the only force acting to retract the first stage cylinder. This completes the lowering of the dump body.RAISE Position
Control Valve In RAISE Position
(1) Pump relief valve. (2) Inlet for pump oil. (3) Check valve. (4) Spring on valve spool. (5) Detent ball (four). (6) Passage to oil cooler for brakes and to the hydraulic tank. (7) Passage for rod ends of hoist cylinders. (8) Passage for head ends of hoist cylinders. (9) Valve spool. (A) RAISE position. (B) HOLD position. (C) FLOAT position. (D) LOWER position.The oil from the pump flows into the control valve through inlet (2). With valve spool (9) held in the RAISE position, passage (6) is not open to pump oil. When the pump oil cannot flow out through passage (6), there is an increase in the pressure. The pressure of the pump oil opens check valve (3). The pump oil flows through the open check valve, around valve spool (9) through passage (8) and to the head ends of the cylinders.The pump oil in the head ends of the cylinder moves the cylinders toward their extended lengths and the dump body lifts. When the pump oil in the head ends of the cylinders moves the cylinders, the oil in the rod ends of the cylinders is pushed through passage (7) around valve spool (9) and through passage (6) to the oil cooler, the brakes on the rear wheels, and then to the hydraulic tank.When the hoist control lever is released, the spring (4)