PLATE AS 7V8817 - Caterpillar

Main Control Valve
The main control valve is situated in the hydraulic circuit between the main hydraulic pumps and the implement cylinders, the travel motors and the swing motor. The main hydraulic pumps supply high pressure hydraulic oil to the main control valve. Pilot pressure oil from the pilot manifold is used by the operator controls to command the movement of nine primary valve spools in the main control valve. The nine primary valve spools, in turn, control the flow of the high-pressure oil to the implement cylinders and motors. The main control valve determines the direction and speed of the implement cylinders and motors in proportion to the movement of the operator joysticks and travel lever/pedals. The nine primary valve spools control the following components:
Left travel motor (FORWARD and REVERSE)
Right travel motor (FORWARD and REVERSE)
Swing motor (LEFT and RIGHT)
Bucket cylinder (OPEN and CLOSE)
Stick cylinder (IN and OUT)
Boom cylinders (RAISE and LOWER)The Back-To-Back (BTB) main hydraulic control valve is a mono-block design. The valve is divided into the front half and the rear half. High-pressure pump supply oil enters the oil inlets at the bottom and flows upward through the main valve body. The drive pump provides oil flow to the front half of the main control valve. The idler pump provides oil flow to the rear half of the main control valve.Other components of the main control valve include:
Boom drift reduction valve and stick drift reduction valve
Boom regeneration valve and boom regeneration PRV
Stick regeneration valve and unloading valve
Swing priority valve and swing priority solenoid
Straight travel valve and straight travel solenoidNote: Refer to the appropriate sections in this manual for more information.