COVER-WATER PUMP 3697512 - Caterpillar

Illustration 1 g00473687
Hydraulic schematic for pilot oil (1) Solenoid valve (swing parking brake) (2) Swing parking brake (3) Displacement change valve (left travel) (4) Displacement change valve (right travel) (5) Line (6) Line (7) Stick drift reduction valve (8) Control valve (left travel) (9) Control valve (straight travel) (10) Main control valve (11) Pressure switch (implement and swing) (12) Pressure switch (travel) (13) Control valve (right travel) (14) Control valve (boom I) (15) Boom drift reduction valve (16) Line (17) Line (18) Passage (19) Passage (20) Logic valve (21) Main relief valve (22) Passage (23) Pressure control valve (24) Pressure switch (boom raise) (25) Pilot control valve (left and right travel) (26) Line (27) Line (28) Pilot control valve (stick and swing) (29) Line (30) Pilot control valve (bucket and boom) (31) Line (32) Solenoid valve (fine control) (33) Solenoid valve (travel speed) (34) Solenoid valve (swing priority mode) (35) Proportional reducing valve (36) Pilot manifold (37) Line (38) Passage (39) Hydraulic activation control valve (40) Passage (41) Passage (42) Pilot relief valve (43) Line (44) Upper pump (45) Lower pump (46) Pilot pump (47) Line (48) Pilot filterPilot Oil Circuit
Pilot system oil from pilot pump (46) has the following three main functions: (1) Control main pump output. (2) Operate the control valves. (3) Create pilot oil pressure in order to achieve various operations.The pilot oil from pilot pump (46) flows through pilot filter (48) and line (47). The pilot oil then enters pilot oil manifold (36). The pilot oil is then separated into the following circuits through respective lines (29) and (43), and passages (38), (40), and (41) .Proportional Reducing Valve Circuit
Pilot oil from passage (38) flows to proportional reducing valve (35). The pilot oil is changed into a hydraulic signal of power shift pressure. The hydraulic signal flows through line (37) to the regulators of main pumps (44) and (45). The hydraulic signal controls the pump output.Note: For more information on the regulators and main pumps, refer to Systems Operation, "Piston Pump (Main)".Pilot Control Valve Circuits
Pilot control valve circuits direct pilot pump oil through pilot filter (48) to hydraulic activation control valve (39). Pilot oil then flows to pilot control valves (25), (28), and (30) .When an implement and/or swing control is operated, pilot pump oil flows to the main control valves. The pilot oil shifts the stem of the selected main control valves in order to operate a cylinder and/or a motor. Control valve (14) is controlled by pilot oil from line (17) or line (31). Control valve (14) is for the operation of Boom I.When the boom is lowered or the stick is moved inward, the pilot oil from line (16) or line (6) activates boom drift reduction valve (15) or stick drift reduction valve (7) .When the boom control lever is moved to the LOWER position, pilot oil from pilot control valve (30) flows through line (16) to boom drift reduction valve (15). Boom drift reduction valve (15) allows return oil flow from the