BEARING 4515937 - Caterpillar

Main control valve (3) is located in the hydraulic system between the main pumps and actuators (cylinders and motors). Depending on the machine operation, the oil flow from drive pump (36), idler pump (39) and pilot pump (38) to the hydraulic circuits are controlled by the operation of each component in the main control valve. By this control, the speed and direction of the cylinders and the motors can be controlled and adjusted. The pump delivery pressure can be controlled and adjusted.Main control valve (3) is a back to back design that uses a single valve body. The main control valve uses internal passages to combine flow for the boom and stick circuits.
The drive pump oil is delivered through pressure port (22), center bypass passage (27), and return port (6) to hydraulic tank (40). The drive pump delivers oil to the following components:
Straight travel control valve (19)
Left travel control valve (24)
Boom I control valve (25)
Bucket control valve (29)
Stick II control valve (31)
The idler pump oil is delivered through pressure port (21), center bypass passage (8), and return port (6) to hydraulic tank (40). The idler pump delivers oil to the following components:
Straight travel control valve (19)
Right travel control valve (18)
Boom II control valve (17)
Swing control valve (14)
Stick I control valve (10)
In addition, the following components are located in main control valve body (41).
The line relief valve (bucket cylinder rod end) (9) and the line relief valve (bucket cylinder head end) (30) limit the pressure in the bucket hydraulic system due to external forces.
When the joysticks and/or travel levers/pedals are in the NEUTRAL position, or when the joysticks and/or travel levers/pedals are partially moved from the NEUTRAL position, negative flow control relief valve (1) and the negative flow control orifice (2) decrease the pump flow.
When the joysticks and/or travel levers/pedals are in the NEUTRAL position, or when the joysticks and/or travel levers/pedals are partially moved from the NEUTRAL position, negative flow control relief valve (5) and the negative flow control orifice (4) decrease the pump flow.
The line relief valve (boom cylinder rod end) (16) limits the pressure in the boom hydraulic system due to external forces.
Boom regeneration valve (15) supplies return oil from the head end of the boom cylinders to the rod end of the boom cylinders when the boom is lowered.
Stick regeneration valve (33) supplies return oil from the rod end of the stick cylinder to the head end of the stick cylinder during the stick in function.
Stick unloading valve (32) reduces the back pressure in the rod end of the stick cylinder during the stick IN function.
Load check valve (28) and load check valve (12) are part of the following control valves: bucket control valve (29), boom I control valve (25), stick II control valve (31), boom II control valve (17), swing control valve (14) and stick I control valve (10).
The line relief valve (stick cylinder rod end) (7) limits the pressure in the stick hydraulic system due to external forces.
Main relief valve (20) limits the