ENGINE AR-COMPLETE 1861861 - Caterpillar

Illustration 1 g06213521
Main control valve
(1) Boom drift reduction valve
Illustration 2 g06243673
Boom drift reduction valve
(3) Passage to head end of boom cylinders
(6) Passage
(7) Drift reduction valve
(8) Spool
(11) Passage
(12) SpringBoom Raise
Illustration 3 g06213900
Boom drift reduction valve (BOOM RAISE)
(2) Passage from boom 2 control valve
(3) Passage to head end of boom cylinders
(4) Passage from boom cylinder retract solenoid
(5) Passage
(6) Passage
(7) Drift reduction valve
(8) Spool
(9) Drain passage
(10) Spring chamber
(11) Passage
(12) Spring
(13) Passage from boom 1 control valve
(14) SpringWhen raising the boom, pilot oil is not sent from the pilot manifold to passage (4) of the boom drift reduction valve. Spool (8) does not shift.The oil flow from the boom 2 control valve in passage (2) and boom 1 control valve in passage (13) combines in the main control valve at the boom drift reduction valve passage (6). As the oil pressure in passage (6) increases, valve (7) shifts against the force of spring (12). The oil in spring chamber (10) flows through passages (5) and (11) to passage (6). The oil fllow in passage (6) now flows to the head end of the boom cylinders through passage (3).Boom Lower
Illustration 4 g06279188
Boom drift reduction valve (BOOM LOWER)
(2) Passage from boom 2 control valve
(3) Passage to head end of boom cylinders
(4) Passage from boom cylinder retract solenoid
(5) Passage
(6) Passage
(7) Drift reduction valve
(8) Spool
(9) Drain passage
(10) Spring chamber
(11) Passage
(12) Spring
(13) Passage from boom 1 control valve
(14) SpringWhen lowering the boom, pilot oil is sent from the pilot manifold to passage (4) of boom drift reduction valve (1). Spool (8) shifts against spring (14). The oil in spring chamber (10) flows through passage (5), and the orifice in spool (8). The oil in spring chamber (10) also flows through drain passage (9) to the hydraulic tank.The return oil from the boom cylinder head end enters passage (3). Since the pressure in spring chamber (10) is low, the oil in passage (3) shifts valve (7) against the force of spring (12). The oil from the head end of the boom cylinders flows through passage (6) to the boom 1 control valve.