BREATHER AS 2477169 - Caterpillar

Illustration 1 g06248286
Boom Lowering Control Valve
(7) Line relief valve
(11) Valve
(14) Spool
Illustration 2 g06217703
Partial schematic (BOOM UP)
(1) Boom cylinders
(2) Boom lowering control valves
(3) Main control valve
(4) Boom 1 cylinder extend solenoid
(5) Boom 2 cylinder extend solenoid
(6) Port to boom cylinder head end
(8) Ports to main control valve (pilot oil)
(17) Ports to main control valve
(19) Ports to drainBOOM RAISE Operation
Illustration 3 g06248279
Boom raise operation
(6) Port to boom cylinder head end
(7) Line relief valve
(8) Ports to main control valve (pilot oil)
(9) Passage
(10) Spring
(11) Valve
(12) Passage
(13) Passage
(14) Spool
(15) Passage
(16) Passage
(17) Ports to main control valve
(18) Spring
(19) Ports to drainWhen the operator moves the joystick to the Boom raise position, pump oil flows from main control valve (3) through a line to port (17) on boom lowering control valves (2).The pump oil flows into passage (16) and the pressure of the pump oil causes valve (11) to shift against spring (10). The pump oil flows through passage (16) to passage (12) to port (6) to the boom cylinder head end. The rod of boom cylinder (1) will extend to raise the boom.When the joystick is returned to the NEUTRAL position, boom cylinders are held in the raised position. Valve (11) prevents the oil in