HOSE AS 1864124 - Caterpillar

Lift Circuit
Lift Circuit in RAISE Position
(1) Oil filter. (2) Filter bypass valve. (3) Lift cylinder makeup valve (rod end). (4) Tilt cylinder relief valve (rod end). (5) Tilt cylinder relief valve (head end). (6) Orifice. (7) Tilt cylinder makeup valve (rod end). (8) Lift control valve spool. (9) Tilt control valve spool. (10) Tilt cylinder. (11) Lift cylinders (two). (12) Load check valve for lift cylinders. (13) Load check valve for tilt cylinder. (14) Lift cylinders relief valve (head end). (15) Oil pump. (16) Raise detent. (17) Tilt detent. (18) Main relief valve. (19) Oil tank. (20) Oil cooler. (21) Oil cooler supply valve.Raise Operation
When the engine is running with the control levers in HOLD position, oil pump (15) takes oil from oil tank (19) and sends it first to main relief valve (18) which controls the maximum pressure in the system. The oil then goes through the lift and tilt control valve because both spools are in HOLD position. From here, the oil goes on to makeup valves (3) and (7), through orifice (6) to oil cooler supply valve (21). From the supply valve, the oil is sent to oil cooler (20), oil filter (1), filter bypass valve (2), and back to oil tank (19).When there is a sudden increase (surge) in line pressure, supply valve (21) diverts oil directly to oil filter (1). This provides protection to oil cooler (20) against pressure surges.When the lift control lever is moved to RAISE detent position, lift control valve spool (8) moves to RAISE position and detent (16) engages with the spool. The pump pressure increases and causes load check valve (12) to open. The oil from the pump now goes to the head end of lift cylinders (11) and causes the cylinder pistons and rods to extend. The lift arms cause the bucket to raise. The movement of the cylinder pistons and rods pushes oil out of the rod end of the cylinders. This oil comes into the lift and tilt control valve and goes around spool (8) on its way back to oil filter (1) and oil tank (19).When the lift control lever manually moves lift control valve spool (8) out of detent (16) or if the lift kickout mechanically moves the lift control valve spool out of the detent, the springs on the end of the valve spool move the spool back to HOLD position. In this position, lift control valve spool (8) stops the flow of oil to the lift cylinders and holds the oil in both ends of the cylinders. The cylinder pistons and rods stop their movement and the lift arms and bucket are held up until the lift control lever is moved again.Lower Operation
When the lift control lever is moved to LOWER position, lift control valve spool (8) is move to LOWER position. The oil flow to lift cylinders (11) is the reverse of bucket RAISE. The oil pressure increases and causes load check valve (12) to open. The oil now goes