Frame size cm
3
28/32 41/51
Control MDC/EDC/HC-EDC NFP MDC/EDC/HC-EDC NFP
Lock nut mm 13 17 17 17
Servo adjust screw mm [in] 5 7 7 7
Lock nut torque N•m [lbf•ft ] 23 [17] 40 [30] 40 [30] 40 [30]
Control neutral adjustment for MDC and EDC/HC-EDC
Control neutral adjustment aligns the pump swashplate and the control spool so that a zero angle
control setting provides a zero degree swashplate setting. Perform this adjustment whenever you adjust
or move any part of the control or swashplate mechanism or after you adjust the pump neutral setting.
Warning
The following procedure requires the vehicle/machine to be disabled (wheels raised off the ground, work
function disconnected, etc.) while performing the procedure in order to prevent injury to the technician
and bystanders.
1. Disconnect the external control linkage (for MDC) or control signal input (for EDC and HC-EDC) from
the pump.
2. Install pressure gauges in the servo gauge ports M4 and M5 to measure pressure on the pump servo
piston.
3. Start the prime mover and run at normal operating speed.
4. Loosen the control neutral adjustment seal lock nut (D015).
5. Turn the adjustment screw (D014) clockwise until one of the gauges registers an increase in pressure
on the servo piston. Mark the position of the adjustment screw.
Turn the screw counterclockwise until the other gauge registers an increase in pressure on the servo
piston. Mark the position of the adjustment screw.
Turn the adjustment screw clockwise so that it is midway between the marks. Adjustment screw
movement produces constant change for both directions, so both the pressure gauges should
indicate nearly equal pressures.
6. While holding the adjustment screw (D014) in position, torque the seal lock nut (D015) to 04 N•m [30
lbf•ft].
7. Stop the prime mover and remove the pressure gauges. Remove the plugs in the gauge ports.
8. Connect the external control linkage (for MDC) or control signal input (for EDC and HC-EDC) to the
pump. Reconnect the work function.
Service Manual
Series 42 Axial Piston Closed Circuit Pumps
Adjustments
520L0638 • Rev 0300 • July 2015 33
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