HOSE AS 3463649 - Caterpillar

The control piston has strong centering springs to ensure that once the pump is adjusted for neutral position it will always return to neutral. If an adjustment is necessary follow the steps listed below. To ensure there will be no control pressure at the control module during the centering operation, remove the piping assembly. All sizes require 19mm box wrench.Plug the control pressure outlet port before running the pump. Block pump ports A & B, or install a hydraulic motor. The control pressure outlet port has an M14x1.5 thread. Use a M14x1.5 plug (Part Nbr 76116-001), or combination of M14x1.5 to 9/16-18UNF adapter (Part Nbr 5974-101-002) and 9/16-18UNF plug, to plug this port during the mechanical centering operation.Alternate method to neutralize control: Instead of removing control pipe, connect ports X3 & X4 by means or a low pressure hose. With pressure gauges installed at MA and MB as per Page 12, and with the pump running, loosen the jam nut and turn the adjusting screw until equal pressure (charge pressure) is registered on the two gauges. Alternatively, if a hydraulic motor is connected to the pump, turn the adjusting screw until the motor shaft does not rotate. Tighten the jam nut, stop the pump drive, remove the plug in the control pressure port, open ports A & B, and reinstall the control pressure pipe.Alternate method: Remove the low pressure hose connecting ports X3 & X4 and plug ports X3 & X4.