JLG 18RS Service Manual - Manual (Page 129)

SECTION 5 - HYDRAULICS
3121284 – JLG Lift – 5-39
Control Neutral Adjustment
NOTE: Adjustment of the EDC is very sensitive. Be sure to hold the
hex wrench steady while loosening the locknut. Total
adjustment is less than 120 degrees.
All functions of the Electric Displacement Control (EDC) are
preset at the factory. Adjust the pump to neutral with the
pump running on a test stand or on the vehicle/machine with
the prime mover operating. If adjustment fails to give satisfac-
tory results, you may need to replace the control or coils. See
Minor repair for details.
UNINTENDED MOVEMENT OF THE MACHINE OR MECHANISM MAY CAUSE
INJURY TO THE TECHNICIAN OR BYSTANDERS. TO PROTECT AGAINST UNIN-
TENDED MOVEMENT, SECURE THE MACHINE OR DISABLE/DISCONNECT THE
MECHANISM WHILE SERVICING.
1. Install a 50 bar [1000 psi] gauge in each of the two servo
gauge ports (M4 and M5). Disconnect the external con-
trol input (electrical connections) from the control. Start
the prime mover and operate at normal speed.
2. Use a 4mm internal hex wrench to hold the neutral
adjusting screw (D015) stationary while loosening the
locknut (D060) with a 13mm wrench.
3. Observe pressure gauges. If necessary, turn adjusting
screw (D015) to reduce any pressure differential.
4. Rotate the neutral adjusting screw (D015) clockwise
until the pressure increases on the gauge. Note the
angular position of the wrench. Then rotate the neutral
adjusting screw counter clockwise until the pressure
increases by an equal amount on the other gauge. Again
note the angular position of the wrench.
5. Rotate the neutral adjusting screw clockwise half the
distance between the wrench positions noted above.
The gauges should read the same pressure, indicating
that the control is in its neutral position.
6. Hold the neutral adjusting screw stationary and tighten
the lock nut (D060). Torque to 10 N•m [7 lbf•ft]. Do not
over torque the nut. 7. When the neutral position is set,
stop the prime mover, remove the gauges, and install
the gauge port plugs. Reconnect the external control
input.
Figure 5-43. Control Adustment