JLG 1850SJ Service And Maintenance Manual page 389

4. After establishing the desired maximum displacement
setting, hold adjusting screw in place and tighten the
locknut. Torque to 23 Nm [17 lbft]. C
BE SURE SERVO CYLINDER DOES NOT ROTATE WHEN DISPLACEMENT LIM-
ITER LOCKNUT (E550) IS TORQUED.
5. One turn of the adjusting screw will change the maxi-
mum displacement approximately as follows.
Table 5-40. Displacement Limiter Adjustment Data
Locknut wrench
Displacement
size and torque
45 13 mm 23 Nm [17 lbft] 4 mm internal hex
CONTROL NEUTRAL ADJUSTMENT
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.
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 stationary while loosening the locknut
with a 13mm wrench.
Servo pressure gauge port M5
0 - 50 bar [0 - 1000 psi]
3/16 in
12 N•m [9 lbf•ft]
Servo pressure gauge port M4
0 - 50 bar [0 - 1000 psi]
3/16 in
12 N•m [9 lbf•ft]
3121619
SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
Approximate
displacement
Adjusting screw
change per
size
revolution of
adjusting screw
5.1 cc / turn
Locknut
13 mm
10 N•m
[7 lbf•ft]
Figure 5-132. Control Neutral Adjustment
3. Observe pressure gauges. If necessary, turn adjusting
screw to reduce any pressure differential.
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.
4. Rotate the neutral adjusting screw clockwise until the
pressure increases on the gauge. Note the angular posi-
tion of the wrench. Then rotate the neutral adjusting
screw counterclockwise until the pressure increases by
an equal amount on the other gauge. Again note the
angular position of the wrench.
Solenoid shaft
Control spool
Feedback pin
Maximum
adjustment
less than 120°
Illustration shows how eccentric cam on
adjusting screw rotates to adjust neutral.
Neutral adjusting screw
4 mm
Se rvo pressure gauge port M4
0 - 50 bar [0 - 1000 psi]
3/16 in
12 N•m [9 lbf•ft]
Se rvo pressure gauge port M5
0 - 50 bar [0 - 1000 psi]
3/16 in
12 N•m [9 lbf•ft]
Adjusting
screw
(cam)
5-137