JLG 18RS Service Manual - Manual (Page 131)

SECTION 5 - HYDRAULICS
3121284 – JLG Lift – 5-41
7. Remove all gauges and replace gauge port plugs.
SERVO ADJUSTMENT SIDE M4
1. Run prime mover at 1800 rpm.
2. If using a PWM signal to set mechanical neutral, start
with the electronic control testing tool off (no current to
either solenoid). Check to be sure the servo pressure dif-
ferential is less than 1.5 bar [22 psi]. Reference Sauer-
Danfoss testing specifications TS-392 or control neutral
adjustment page 35.
3. Turn neutral adjust excenter screw (or supply current to
solenoid C2) until the servo pressure at port M5 is 1 - 2
bar [14– 29 psi] greater than at port M4.
4. The system pressure differential must be greater than
zero and the pressure at port A (B for clockwise rotation)
must be greater than the pressure at port B (A for clock-
wise rotation). This step ensures the servo is in contact
with the servo cylinder on side M4.
5. Slowly turn in the servo cylinder on the M4 side until the
system pressure differential starts to decrease. The servo
pressure differential must be maintained between 1-2
bar [14-29 psi] during this step. Continue turning in the
servo cylinder until the system pressure differential is
less than 1.5 bar [22 psi]. This procedure sets the servo
and swashplate to mechanical neutral.
Verify neutral setting
1. If using a PWM signal to set mechanical neutral, check
that servo pressure differential is less than 1.5 bar [22
psi]. Refer to TS-392 or Control neutral adjustment page
35.
2. To verify mechanical neutral, provide current to solenoid
C1, or turn neutral adjust excenter screw, until the servo
pressure differential is 3 bar [43 psi]. The system pres-
sure differential must be below 1.5 bar [22 psi]. Repeat
test on solenoid C2 side.
3. The current required to set the servo pressure differen-
tial to 3 bar [43 psi] should be the same for each sole-
noid. Refer to TS-392.
4. If using neutral adjust excenter screw to set mechanical
neutral, reset control neutral (see page 35).
Standard Procedures, Removing the Pump
Before working on the pump, thoroughly clean the outside. If
the pump has an auxiliary pump attached, remove both
pumps as a single unit. Tag and cap all hydraulic lines as they
are disconnected, and plug all open ports to ensure that dirt
and contamination do not get into the system.
CONTAMINATION CAN DAMAGE INTERNAL COMPONENTS AND VOID THE MAN-
UFACTURER’S WARRANTY. TAKE PRECAUTIONS TO ENSURE SYSTEM CLEANLI-
NESS WHEN REMOVING AND INSTALLING SYSTEM LINES.
DISASSEMBLY
1. With the prime mover off, thoroughly clean all dirt and
grime from the outside of the pump.
2. Tag, disconnect, and cap each hydraulic line connected
to the pump. As hydraulic lines are disconnected, plug
each open port, to ensure that dirt and contamination
do not get into the pump.
3. Remove the pump and its auxiliary pump (if applicable)
as a single unit. Be careful, do not damage solenoids and
Figure 5-45. Servo Adjustment