KIT-SEAL- 5275452 - Caterpillar

Location and Function
Illustration 1 g00954027
The access panels for the pump compartment are on the left side of the machine.
Illustration 2 g00954028
Upper and Lower Pump Stacks (1) Upper pump stack (2) Lower pump stack (3) Charge pump (4) Electronic displacement control valve (EDC valve)EDC valve (4) is for the left drag conveyor piston pump. The drag conveyor is only able to move in the reverse direction. As a result, only one solenoid is used on this EDC valve. There is an EDC valve for the right drag conveyor piston pump that is on lower pump stack (2) . The following text will only explain the operation of EDC valve (4) . The EDC valve has two 12 volt solenoids.Components
Illustration 3 g01526501
Upper Pump Stack (4) EDC valve (5) Solenoid (forward) (6) Solenoid (not used) (7) Port "M4" (8) Port "M5"Only solenoid (5) (forward) is used on EDC valve (4) . Ports "M4" and "M5" can be used to monitor the pressure that goes to the swashplate piston.
Illustration 4 g00954038
Hydraulic Schematic (4) EDC valve (5) Solenoid (9) Servo control cylinder (10) Linkage (11) Servo control valve (12) Swashplate piston (13) Piston pump (drag conveyor) (14) Forward combination valve (15) Charge pump (16) Reverse combination valve (17) Charge pressure relief valveOperation and Oil Flow
Note: Illustration 5 shows the upper pump stack. The upper pump stack contains the EDC valve that controls the piston pump for the left drag conveyor motor. The lower pump stack contains the EDC valve that controls the piston pump for the right drag conveyor motor. The only difference between the upper and lower pump stacks is that the upper pump stack contains the charge pump. The charge pump provides charge pressure oil for the upper and lower pump stacks. The lower pump stack is not shown in this section.
Illustration 5 g00954040
Hydraulic Schematic (4) EDC valve (5) Solenoid (9) Servo control cylinder (10) Linkage (11) Servo control valve (12) Swashplate piston (13) Piston pump (drag conveyor) (14) Forward combination valve (16) Reverse combination valve (17) Valve envelope (18) Valve envelope (19) Valve envelope (20) Valve envelope (21) Line to oil cooler bypass manifold (22) Line from drag conveyor motor (23) Line from charge filter (24) Line to drag conveyor motor (25) Charge pressure relief valve (AA) System pressure (AB) Charge pressure (AC) Sump (AD) Activated components (AE) First pressure reduction (AF) Reduced charge pressureReferenceSee Systems Operation, "Piston Pump (Drag Conveyor)" for information about the forward and reverse combination valves.Note: The drag conveyors can not be run in the forward direction. As a result, only one solenoid on the EDC valve is used. This solenoid controls the piston pump so that system pressure oil will only flow from the line to drag conveyor motor (24) .Charge Pressure Oil
When the machine is started, hydraulic oil is drawn through a suction screen in the hydraulic tank by the charge pump. The charge pump sends charge pressure oil through the line from the charge filter (23) . Charge pressure oil supplies EDC valve (4) and servo control valve