MANIFOLD 2857940 - Caterpillar

Illustration 4 g03859519
(28) Sensor (oil temperature) The gauge - sight (hydraulic tank) (27) is located inside the engine bay on the right hand frame wall. Maintain the oil level midway between the upper and lower gauge lines. Refer to the Operation and Maintenance Manual, "Hydraulic System Oil Level - Check" for more information.Sensor (oil temperature) (28) is located in the implement pump inlet tube. The sensor is a passive sensor with an operating range of 93° 1°C (199.4° 1.8°F) to 90° 1°C (194.0° 1.8°F).
Illustration 5 g03860119
(12) Pump (charge)
(13) Pump (implement)
(25) Pump (high flow) Hydraulic oil from the tank (hydraulic) (10) flows into the first section of the pump (implement) (13). The pump (implement) (13) shares a common supply oil with the pump (charge) (12). The gear pumps are driven by a common drive shaft that runs through the pump (hydrostatic transmission) (15). The pump (charge) (12) supplies oil to the hydraulic system and to the hydrostatic system.
Illustration 6 g03866539
(20) Motor (demand fan)
(18) (SOS) scheduled oil sample port
Illustration 7 g03866535
(20) Motor (demand fan)
(29) Check valve
(30) Relief valve (electrohydraulic proportional) Hydraulic oil for the motor (demand fan) (20) is supplied by the pump (charge) (12). Hydraulic oil from the tank (hydraulic) (10) flows to the front section of the pump (implement) (13). The oil flows from the pump (charge) (12) to the motor (demand fan) (20). The flow of oil through the gear motor turns the fan that cools the hydraulic oil that passes through the cooler (11) Tap (18) is the "SOS" tap for the hydraulic system.The fan motor will rotate in direct relation to the amount of hydraulic oil flow until the hydraulic oil pressure reaches the setting for the relief valve (electrohydraulic proportional) (30). The relief valve (electrohydraulic proportional) allows the excess oil to bypass the gear motor. The relief valve (electrohydraulic proportional) is not a mechanical type of valve. The relief valve (electrohydraulic proportional) is controlled by the ECM based on input by the engine coolant temperature sensor and the hydraulic oil temperature sensor. Use the Caterpillar Electronic Technician software in order to calibrate the demand fan. For more information on the calibration of the demand fan, refer to Hydraulic System Testing and Adjusting, "Gear Motor (fan) - Test".The check valve (29) allows the gear motor to spin freely after the engine is turned off.
Illustration 8 g03860726
Some parts removed for clarity
(19) Filter (hydraulic oil)
(31) Switch (pressure) Hydraulic oil then flows out of the motor (demand fan) (20) and into the filter (hydraulic oil) (19). The filter (hydraulic oil) is located in the engine compartment. The filter (hydraulic oil) is a 5 micron filter. The filter (hydraulic oil) removes any particles that could damage the piston pump. From the filter (hydraulic oil) , the hydraulic oil flows into the front section of the Pump (hydrostatic transmission) (14).
Illustration 9 g03866536
(19) Filter (hydraulic oil)
(32) Differential pressure indicator
(33) Valve (bypass) The filter (hydraulic oil) contains a valve (bypass). Valve (bypass) (33) opens when a differential pressure of 345 kPa (50 psi) is