BODY-PISTON 7S7783 - Caterpillar

Table 1
Required Tools    
Part Number    Part Description    Qty    
6V-3989     Unvalved Nipple     2    
6V-4143     Coupler Assembly     4    
6V-3014     Hose     2    
8T-0855     Pressure Gauge     1    
8T-0861     Pressure Gauge     2    
Illustration 1 g00294305
The pressure taps are located in the battery compartment. (1) Main pump pressure (2) Load sensing signal pressure
Connect a 4000 kPa (580 psi) pressure gauge to pressure tap (1) .
Start the engine.
Lower the left console.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Place the AEC switch in the OFF position.Low Pressure Standby Test
Place the engine speed dial in the MIDDLE IDLE position.
Check the main pump pressure at pressure tap (1) .
Refer to Testing and Adjusting, "Specifications" for the correct low pressure standby.
If the low pressure standby is not correct, the setting should be adjusted. Prior to adjusting the low pressure standby, perform the margin pressure test.
Stop the engine.
Remove the 4000 kPa (580 psi) pressure gauge from pressure tap (1) .Margin Pressure Test
Connect 60000 kPa (8600 psi) pressure gauges to pressure taps (1) and (2) .
Start the engine and place the engine speed dial in the MIDDLE IDLE position.
Place the power mode switch in the MODE II position.
Lower the left console.
Stall the stabilizers or the bucket.
Check the margin pressure on the pressure gauges. Margin pressure is the difference between the pressure at pressure tap (1) and pressure tap (2). Refer to Testing and Adjusting, "Specifications" for the correct margin pressure.
If margin pressure or low pressure standby are out of specification, the spring for the load sensing spool needs to be adjusted.
Stop the engine.Adjust
Connect a 4000 kPa (580 psi) pressure gauge to pressure tap (1) .
Start the engine.
Lower the left console.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Place the AEC switch in the OFF position.
Place the engine speed dial in the MIDDLE IDLE position.
Illustration 2 g00294407
Bottom of main pump (3) Adjustment screw (Margin pressure)
Loosen the locknut on adjustment screw (3) .
Turn adjustment screw (3) until the low pressure standby is set to the proper specification. Refer to Testing and Adjusting, "Specifications" for the correct low pressure standby.Note: Turn adjustment screw (3) clockwise in order to increase the low pressure standby. Turn adjustment screw (3) counterclockwise in order to decrease the low pressure standby.Note: Turn adjustment screw (3) by a 1/8 turn in order to change the pressure by approximately 600 kPa (90 psi).Note: Always make the final pressure adjustments on the pressure rise.
Tighten the locknut.
Stop the engine.
Repeat the margin pressure test.
Repeat the "Adjust" procedure, as needed.