Rayco C275, Operator, Service, Maintenance Manual

Page: 71 / 94

71
9
Series 42 Adjustments and Minor Repairs
4.2 Pump “Neutral” Adjustment
Pump "Neutral"
Adjustment Seal
Lock Nut
Pump "Neutral"
Adjustment Screw
The pump neutral adjustment sets the position of the
servo piston and pump swashplate relative to the
controlling mechanism.
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 machine function.
2. Connect a hose between gauge ports M4 and M5
to equalize the pressures on both ends of the
pump servo piston.
3. Install pressure gauges in gauge ports M1 and
M2 to measure system pressure.
4. Start the prime mover and operate at normal
speed.
5. Loosen the pump "neutral" adjustment seal lock
nut [28cc 13 mm Hex; 41cc 17 mm Hex
]
. Turn
the pump "neutral" adjustment screw [28cc 5
mm Hex; 41cc 7 mm Hex
]
until the system
pressure gauge readings are equal.
6. Turn the adjustment screw clockwise until one of
the gauges registers an increase in system pres-
sure. Note the position of the adjustment screw.
Turn the screw counterclockwise until the other
gauge registers an increase in system pressure.
Note the position of the adjustment screw.
7. Turn the adjustment screw clockwise to a posi-
tion halfway between the positions noted above.
The system pressure gauges should indicate
equal pressures.
8. While holding the adjustment screw in position,
torque the seal lock nut [28cc 20-26 Nm (15-19
ft•lbf); 41cc 28-51 Nm (21-37 ft•lbf)] .
9. Stop the prime mover and remove the hose
between gauge ports M4 and M5. Remove the
pressure gauges installed in gauge ports M1 and
M2. Reinstall the plugs in the gauge ports.
10. Reconnect work function.
IMPORTANT
If the pump is equipped with an MDC or EDC,
the CONTROL "neutral" adjustment MUST also
be performed before putting the pump into
service (see next section).
Pump Neutral Adjustment Screw
(MDC Control Shown)
E100002 E