JLG 600A_AJ Service Manual - Manual (Page 242)

SECTION 5 - HYDRAULICS
5-32 – JLG Lift – 3121201
SWASHPLATE NEUTRAL ADJUSTMENT
1. Using a low pressure line (500 psi [35 Bar] min.),
cross port servo port F to servo port G. This
removes the effects of any control pressure on the
servo piston.
2. Install pressure gauges (10,000 psi [690 Bar]) in the
system pressure gauge ports. Start the engine and
slowly accelerate to normal operating RPM.
3. Remove the protective cap and loosen the servo
lock nut while holding the servo adjustment screw in
position.
4. Turn the servo adjustment screw until the two sys-
tem pressure gauge readings are equal.
5. Turn the servo adjustment screw clockwise until one
of the system pressures starts to increase.
6. Noting the amount of rotation, turn the servo adjust-
ment screw counter-clockwise until the other system
pressure starts to increase.
7. Turn the servo adjustment screw clockwise half the
amount of rotation noted above.
8. While holding the servo adjustment screw from turn-
ing, torque the servo lock nut 13 to 18 ft.lbs. (17.6 to
24.4 Nm). Stop the engine, install a new protective
cap, remove the servo cross-port line, and proceed
to the appropriate control adjustment.
EDC NEUTRAL ADJUSTMENT
1. Remove the electrical connector at the EDC.
Remove the servo cross port line (installed while
making the swash plate neutral adjustment) and
install a 0 to 300 PSI (0 to 21 BAR) gauge in each
servo port.
THE FOLLOWING PROCEDURE MAY REQUIRE THE MACHINE TO
BE DISABLED (WHEELS RAISED OFF THE GROUND, WORK FUNC-
TION DISCONNECTED, ETC.) WHILE PERFORMING THE PROCE-
DURES IN ORDER TO PREVENT INJURY TO THE TECHNICIAN AND
BYSTANDERS.
2. Start the engine and accelerate to normal operating
RPM.
3. Loosen lock nut with 1/2” wrench and slowly rotate
the neutral adjustment screw, with 5/32” internal hex
wrench, until the pressure is equal on both servo
gauges.
4. Slowly rotate the neutral adjustment screw until one
of the servo gauges starts to increase in pressure.
5. Noting the amount of rotation, slowly rotate the neu-
tral adjust screw in the opposite direction until the
other servo gauge begins to increase in pressure.
6. Turn the neutral adjust screw back one - half the
amount noted above. Hold the neutral adjust screw
and torque the lock nut to 25 to 30 in.lbs. (2.8 to 3.4
NM).
7. Stop the engine. Connect the control input. Remove
the servo pressure gauges. Return the machine to
normal operating condition. Restart the engine and
assure that the hydrostatic system is in neutral.