VALVE & LINES GP-PILOT 2434093 - Caterpillar

Schematic
Illustration 1 g03386216
System for the oil return
(1) Swing motor
(2) Right Travel Motor
(3) Left travel motor
(4) Swing motor drain line
(5) Line
(6) Line
(7) Line (case drain)
(8) Line
(9) Line
(10) Main control valve
(11) Right travel control valve
(12) Left travel control valve
(13) Return passage
(14) Return line
(15) Slow return check valve
(16) Oil cooler
(17) Pilot manifold
(18) Main pump
(19) Oil filter
(20) Breather cap
(21) Hydraulic tank
(22) Pilot control valve (boom and bucket)
(23) Pilot control valve (swing and stick) Main pump (18) draws oil from hydraulic tank (21). The oil delivery from main pump (18) will enter main control valve (10) and is used for machine operations. Once machine functions have been performed, the components must send return oil back to hydraulic tank (21). The return oil flows out of the main control valve through return passage (13) and return line (14). Return line (14) directs oil into slow return check valve (15). Reference: For more information on the operation of the slow return check valve, refer to "Slow Return Check Valve"Swing case drain line (4) connects to slow return check valve (15). Travel motor case drain line (7) connects to hydraulic tank (21).Components
Breather cap
Illustration 2 g03386640
Breather cap
(20) Breather cap
(21) Filter screen
(22) Check valve
(23) Check valve
(24) Spring
(25) O-ring Breather cap (20) prevents hydraulic tank (21) from becoming pressurized. Atmospheric pressure will equalize inside hydraulic tank (21) through breather cap (20). Breather cap (20) also prevents contaminants from entering hydraulic tank (21) by using filter screen (21).When the hydraulic fluid empties from hydraulic tank (21), a vacuum condition occurs inside the hydraulic tank. Check valve (22) opens and allows atmospheric pressure into the hydraulic tank.When fluid returns to the hydraulic tank, there is an air pressure build-up inside the tank. Once the air pressure is greater than the pressure of the spring (24), check valve (23) opens. This action allows the built up air pressure to vent to the atmosphere.Slow Return Check Valve
Illustration 3 g03386222
Slow return check valve
(15) Slow return check valve
(26) Check valve
(27) Spring The function of slow return check valve (15) is to create a slight backpressure on the return system. This back pressure feeds the oil makeup lines and prevents a cavitation condition inside swing motor (1) and travel motors (2) and (3).Spring (27) prevents check valve (26) from opening until the oil pressure reaches 100 kPa (14.5 psi). Once the pressure is reached, the hydraulic oil is allowed to flow into hydraulic oil filter (19).Oil Filter
Illustration 4 g03386224
Oil filter
(19) Oil Filter housing
(28) Check valve
(29) Spring
(30) Filter element Note: For additional information on replacing the hydraulic oil filter element, refer to Operation and Maintenance Manual, "Hydraulic System Oil Filter (Return) - Replace".Filter element (30) filters contaminants out of the hydraulic oil. There is a bypass check valve built into oil filter housing (19). This bypass check valve is used if filter element (30) gets clogged.If filter element (30) gets clogged, the pressure buildup on check valve (28) will eventually overcome the opening pressure of spring (29). This pressure will open check valve (28) and allow hydraulic oil to flow into