PISTON 2420841 - Caterpillar

Front Pump
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, PERJ1017, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.Dispose of all fluids according to local regulations and mandates.
Note: Perform the test for the front pump and the test for the rear pump one at a time.
Position the machine on level ground.
Stop the engine.
Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure - Release".
Attach 311-1362 Vacuum Cap onto the hydraulic tank. Attach an air supply hose onto the assembly. Apply 276 to 414 kPa (40 to 60 psi). This procedure will pull a vacuum on the hydraulic system.
Install the tools in accordance with the tool layout. Refer to Illustration 5.
Illustration 8 g03681897
Pump compartment
(1) Pressure tap (delivery pressure for front pump 1)
(2) Pressure tap (delivery pressure for rear pump 2)
(3) Pressure tap (power shift pressure)
(4) Pressure tap (front pump 1 negative flow)
(5) Pressure tap (rear pump 2 negative flow)
(6) Delivery line (front pump)
(7) Delivery line (rear pump)
Disconnect delivery line (6) from the front pump.
Install blocking cover to the end of delivery line.
Assemble and install seal (D16), adapter (D15), seal (D4), elbow (D12), seal (D11), plug (D10), and fitting (D5) on the front pump by using existing half flanges (10), bolts (8) and washers (9).
Illustration 9 g03682272
Main Control Valve
(11) Cover (auxiliary return)
Remove cover (11) and bolts.
Assemble and install seal (D22), adapter (D21), seal (D20), adapter (D19), seal (D4), elbow (D12), seal (D11), plug (D10), and fitting (D5) to auxiliary return.
Remove 311-1362 Vacuum Cap and install the hydraulic cap for the hydraulic tank.
Connect portable hydraulic tester (D) and test hoses between coupling assembly at the front pump and the coupling assembly at the auxiliary return.
Attach a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1) for delivery pressure of the front pump.
Attach a 3,447 kPa (500 psi) pressure sensor to pressure tap (3) to monitor power shift pressure.
Install tooling (C) on the engine to monitor engine speed.Test Procedure
To prevent personal injury or equipment damage from failure of the hydraulic test equipment or associated circuit components because of blocked pump flow, make sure that the test equipment valves are fully open before starting the engine.
To prevent personal injury and/or equipment damage from failed lines or components while the hydraulic test equipment is returned to the open flow position, slowly open the hydraulic test equipment valve while monitoring the pump flow.If pump flow does not increase as the valve is opened, shut the engine off and determine what is preventing the pump from upstroking.
Rear Pump
Insert track block in both tracks to block forward travel.
Start the engine.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Enter the Service Menu on the monitor.
Input the password "9992".
Select "Override Parameters".
Override "Pump #1 Solenoid Current" to 0