HARNESS AS-CHASSIS 4748558 - Caterpillar

Neutral Adjustment Procedure that Uses Pressure Gauges
Table 1
Required Tools    
Part Number     Description     Quantity    
3J-1907     O-ring     2    
6V-3965     Test Fitting     2    
8T-0854     Gauge     2    
8T-0855     Gauge     2    
Illustration 1 g00630302
The neutral adjustment is the only adjustment that can be made on the electrical displacement control (EDC). Adjustment of neutral adjustment screw (1) that is located on the end of the EDC performs the neutral adjustment.
Illustration 2 g00630304
Locate the gauge ports "M4" (2) and "M5" (3) on the bottom of the pump.
Install two 3J-1907 O-Ring Seals and two 6V-3965 Fittings into ports "M4" (2) and "M5" (3) .
Install two 8T-0855 Pressure Gauges on the test fittings.Note: Under normal working conditions, the pressure could be as high as charge pressure. The pressure will be different on each pump. This is due to the different routing of the case drain lines. The left hand pump case drain runs through the case drain filter and the oil cooler. The right hand pump case drain line runs to the front return manifold.
Disconnect the electrical connections for the EDC at the propel pump.Note: If the pressure is brought too high, the gauges could be damaged.
Start the engine and run the engine at high idle until the hydraulic oil temperature is at least 38 °C (100 °F). Read the pressure gauges. If the pressure is below 965 kPa (140 psi), remove the gauges and replace the gauges with two 8T-0854 Pressure Gauges .Note: If the pumps are stroked manually during this procedure, the gauges will be damaged.The pressure reading on the gauges should be equal. If the readings are not equal, use the following steps in order to adjust the adjustment screw for the EDC on the end of the controller.
Use a 13 mm wrench or a 4 mm Allen wrench for the neutral adjustment screw. Rotate the screw clockwise until the pressure increases on one of the gauges. Note the angle of the wrench and note the pressure reading of the gauge.
Rotate the screw counterclockwise until the pressure increases by the same amount that was read on the other gauge. Note the angle of the wrench and note the pressure reading on the gauge.
Rotate the adjustment screw clockwise in order for the screw to be half the distance between the noted positions from the two previous steps. The gauges should read the same pressure within 35 kPa (5 psi) of each other. If the gauges are within 35 kPa (5 psi) of each other, the pumps are in the neutral position. If the gauges are not within 35 kPa (5 psi) of each other, repeat Step 6.
Remove the gauges and remove the fittings. Install the port plugs and reconnect the EDC.
Repeat Step 1 through Step 6 on the opposite pump.
After the neutral adjustment has been completed, recalibrate the initial current to the propel electronic control module for the propel pump. Use the Service Manual, KENR2949, "Propel Electronic Control System" in order