MH3037 Material Handler Machine System Caterpillar

Upper Return Hydraulic System

Illustration 1	g06055124
(1) Swivel (2) Upper main control valve (3) Main pump (4) Swing pump (5) Swing motor (6) Manifold and valve (anti-cavitation) - tank (7) Manifold and valve (anti-cavitation) - cooler (8) Hydraulic oil cooler (9) Return filter (10) Case drain filter - swing (11) Case drain filter - main pump (12) Case drain filter - travel motor and generator (13) Vacuum switch - tank breather restriction (14) Hydraulic oil level sensor (15) Hydraulic oil temperature sensor (16) Hydraulic oil tank

Lower Return Hydraulic System

Illustration 2	g06054948
(1) Swivel (17) Lower main control valve (18) Travel motor (19) Control manifold and solenoid for hydraulic oil warming

The return oil from the cylinders and/or motors now flows through the return passages to the return line.

The return oil from the return passages flows through an anti-cavitation manifold valve. Only oil from the cooler anti-cavitation manifold flows through the oil cooler. Oil from both anti-cavitation manifolds flows through the return filters before entering the hydraulic tank.

Reference: For more information concerning the bypass check valve, refer to Systems Operation, "Bypass Valve (Return)".

Case drain oil from each pump and motor flows into case drain lines, through case drain filters and into hydraulic tank. There are three case drain filters.

• The case drain oil from the swing pump and swing motor combines before entering the case drain filter.

• The case drain oil from the generator pump and generator motor combine with the case drain oil from the travel motor before entering the case drain filter.

• The case drain oil from the main pump flows into a dedicated filter just for the main pump.

For information concerning the makeup operation of the return hydraulic system at the swing motor, refer to the following sections in this manual.

• Systems Operation, "Check Valve (Return Makeup)"

• Systems Operation, "Oil Makeup (Swing System)"

• Systems Operation, "Relief Valve (Swing)"