PUMP GP- 5121045 - Caterpillar

Illustration 1 g03600496
(1) Tank port
(2) Steering port
(3) Load signal port
(4) Relief valve
(5) Priority valve
(6) Pump port
(7) Spring
(8) SpoolThe inlet manifold is bolted to the lift control valve on the loader control bank valve. Relief valve (4) and priority valve (5) are installed in the loader control bank valve. The relief valve prevents the oil pressure in the load signal circuit for the loader function from becoming too high. Load signal oil that has flowed through the relief valve flows out of the inlet manifold through port (1) to the tank.Oil flows from the hydraulic pump through port (6). The supply of oil to the metering pump flows out of port (2). Load signal oil flows from port (3) to the bank valve for the backhoe. Oil returns from the circuits in the loader control bank valve flow to the tank through port (1).Oil enters the priority valve through port (6). Spring (7) holds spool (8) upward preventing the oil from flowing to the control valves in the loader control bank valve. The oil flows around the spool into passage. The oil flows through port (2) to the steering circuit. Some of the oil flows into passages that are cut in the spool.As oil flows into the steering circuit, the oil pressure in the priority valve raises. When the oil pressure overcomes the force of spring (7), spool (8) moves down. The oil flows around the spool to passage. Then, the oil flows to the control valves in the loader control bank valve.The manifold of the loader contains relief valve (4) for the load signal oil. Internal passages in the inlet manifold of the loader connect the load signal oil from the control valves to the load signal oil from the steering circuit. Connecting these circuits allows the circuit with the highest pressure to control the flow of oil from the pump. If the oil pressure in the circuit for the signal oil gets too high, relief valve (4) opens. The oil flows through the relief valve through port (1) to the tank.