TUBE AS 1992458 - Caterpillar

Lower Pump
Illustration 8 g00503310
Pump compartment (15) Delivery line (lower pump) (18) Upper pump (20) Negative flow control line (lower pump) (21) Pressure tap (lower pump delivery pressure) (22) Lower pump
Position the machine on level ground.
Stop the engine.
Release the pressure in the hydraulic system. Refer to Testing And Adjusting, "Hydraulic System Pressure - Release".
Install the following tools in accordance with the circuit diagram. Refer to Illustration 6.
Disconnect delivery line (15) from lower pump (22) .
Install plug (6) and seal (30) to the end of delivery line (15) .
Disconnect makeup line (4) from swing motor (1) .
Install tee (3) to connector (2) of swing motor (1) .
Connect makeup line (4) to tee (3) .
Connect portable hydraulic tester (12) between lower pump (22) and makeup line (4) .
Connect 60000 kPa (8700 psi) pressure gauge (8) to pressure tap (21) for lower pump delivery pressure.
Install multitach group (23) on engine (24). This is used to monitor engine speed.
Disconnect negative flow control line (20) from lower pump (22). Install plug (10) and seal (42) to the end of negative flow control line (20) .
Connect one end of test hose (17) to negative flow signal pressure port (44) of lower pump (22) .
Install tees (14) to the other end of test hose (17). Refer to Illustration 6.
Connect a 6000 kPa (870 psi) pressure gauge (19) to tee (14) .
Connect one end of test hose (46) to pressure tap (13) of pilot oil manifold (11). Connect the other end of test hose (46) to tee (14) .Test
Note: Perform the test for the upper pump and the test for the lower pump one at a time.
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.
Start the engine.
Place the machine controls at the following settings: Power Mode, engine speed dial "10" and AEC switch OFF.Reference: Make reference to Testing And Adjusting, "Operational Checks" for engine rpm settings.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Turn valve (26) on portable hydraulic tester (12) clockwise until the pump delivery pressure is 6850 kPa (1000 psi).
Adjust pilot relief valve (25) on pilot oil manifold (11) until pressure gauge (19) that is connected to tee (14) indicates 2650 kPa (385 psi).
Record the negative flow at 2650 kPa (385 psi) in Table 1.
Illustration 9 g00554178
P-Q characteristic curve
Table 1
Negative Flow Control at
2650 kPa (385 psi)    
6DR1583-UP    
Oil Temperature °C (°F)        
Engine speed (rpm)        
Flow measured liter/min (US gpm)     Upper pump        
Lower pump    
Flow