BUSHING- 4Z9002 - Caterpillar

Boom Hydraulic System
Two boom cylinders are used to RAISE and LOWER the boom. When the boom cylinder rods EXTEND, the boom RAISES. When the boom cylinder rods RETRACT, the boom LOWERS.The main hydraulic pumps supply high-pressure oil to the main control valve. Pilot oil pressure from the pilot manifold is used by the joysticks to control the movement of the boom I control valve and boom II control valve in the main control valve. The boom I and boom II spools, in turn, control the flow of the high-pressure oil to the boom cylinders. The main hydraulic control valve determines the direction and speed of the boom cylinders in proportion to the movement of the joystick.Components of the boom system include:
Boom I control valve and boom II control valve
Boom drift reduction valve
Boom regeneration valve and boom regeneration PRV
Boom priority valve
Boom up limit PRVNote: Refer to the appropriate sections in this manual for more information.