BUSHING-TERMINAL 8X0759 - Caterpillar

When the lift control lever is moved into the RAISE position, the current proportional to the movement of the control lever is directed to the coil on raise solenoid valve (8). The solenoid valve sends a proportional amount of pilot oil to the raise end of lift spool (36). Lift spool (36) begins to shift down.As the lift spool shifts down, supply oil from implement pump (34) is directed to lift pressure compensator valve (37). Load sensing oil is then directed through an orifice and check valve to implement pump margin spool (42). The orifice stabilizes the load sensing signal pressure to the implement pump, to the spring chamber on each compensator valve, and to margin relief valve (7). The load sensing signal moves the pump load sensing spool in the pump control valve to upstroke the pump.The load sensing pressure acts on the top of the margin relief valve (7). During the upstroke of implement pump, margin relief valve (7) maintains an implement pressure equal to the load sensing pressure and the value of the spring. When the control lever is released, the load sensing pressure goes to approximately zero pressure. Margin relief valve (7) opens to relieve supply oil pressure, eliminating pressure spikes in the closed center system.When lift spool (36) directs the pump supply oil to lift pressure compensator valve (37), the valve moves down and oil flows through lift spool (36), and around lift arm anti-drift valve/spool (18) to the head end of lift cylinders (25). As the pressure changes in the head end of lift cylinders (25), lift pressure compensator valve (37) opens and closes to maintain a constant flow for a given control spool displacement.If the machine is equipped with the optional ride control, balance valve solenoid (38) will be energized, allowing oil on the right side of balance valve (41) to flow to hydraulic tank (47). As the pressure in the head end of lift cylinders (25) increases to raise the implements, the oil pressure on the left side of balance valve (41) will force balance valve (41) to shift to the right. Supply oil flows through the check valve, through balance valve (41) to ride control activation spool (22). Oil then, flows through ride control activation spool (22) to ride control accumulator (30).With ride control not enabled, ride control solenoid (13) is de-energized and spring force moves ride control activation spool (22) to the left. Oil flow between the head end of lift cylinders (25) and ride control accumulator (30) is blocked. The oil from the rod end of lift cylinders (25) flows around lift spool (36) to hydraulic tank (47).FLOAT Position
Illustration 8 g06244981
(5) Tilt back solenoid valve
(6) Line relief valve ( tilt) (head end)
(7) Margin relief valve
(8) Raise solenoid valve
(9) Implement pilot supply solenoid valve
(13) Ride control solenoid valve
(14) Lower/float solenoid valve
(16) Load sense relief/bleed valve
(17) Dump solenoid valve
(18) Lift arm anti-drift valve/spool
(20) Ride control manifold
(22) Ride control activation spool
(23) Tilt cylinder
(24) Makeup and line relief valve (tilt)
(25) Lift cylinders
(26)