JLG M450 ANSI Service Manual - Manual (Page 172)

SECTION 5 - HYDRAULICS
5-20 – JLG Lift – 3121127
5.5 PRESSURE SETTING PROCEDURES
Cold temperatures have a significant impact on pressure
readings.JLG Industries Inc. recommends operating the
machine until hydraulic system has warmed to normal
operating temperatures prior to checking pressures. We
also recommend using a calibrated gauge. Pressure read-
ings are acceptable if within +/- 5% of specified pres-
sures.
Main Relief
1. Install pressure gauge at port “G” on Steer/Brake
valve.
2. Activate and bottom out either Upper or Lower Lift
Up. Adjust Main Relief to value given in Table 5-4,
Pressure Settings - Prior to S/N 0300062642 or Table
5-5, Pressure Settings - S/N 0300062642 to Present.
Upper Lift Down Relief
1. With pressure gauge at “G” port on main valve, acti-
vate and bottom out Upper Lift Down.
2. Adjust Upper Lift Relief to value given in Table 5-4,
Pressure Settings - Prior to S/N 0300062642 or Table
5-5, Pressure Settings - S/N 0300062642 to Present..
Lower Lift Down Relief
1. With pressure gauge at “G” port on main valve, acti-
vate and bottom out Mid/Lower Lift Down.
2. Adjust Mid/Lower Lift Relief to value given in Table 5-
4, Pressure Settings - Prior to S/N 0300062642 or
Table 5-5, Pressure Settings - S/N 0300062642 to
Present..
Telescope Relief
1. With pressure gauge at “G” port on main valve, acti-
vate and bottom out Telescope In.
2. Adjust Telescope Relief to value given in Table 5-4,
Pressure Settings - Prior to S/N 0300062642 or Table
5-5, Pressure Settings - S/N 0300062642 to Present..
Platform Level Up Relief
1. On machines prior to S/N 0300062642, install the
pressure gauge at the “G” port on Main Control
valve, activate and bottom out Platform Level Up.
On machines S/N 0300062642 to present, install the
pressure gauge at the "B2" port on the back of the
Main Control Valve, activate and bottom out Platform
Level Up.
2. Adjust Platform Level Up Relief to value given in
Table 5-4, Pressure Settings - Prior to S/N
0300062642 or Table 5-5, Pressure Settings - S/N
0300062642 to Present.
LC LR
TR
T2
B2
B1
S2
S1
R2 R1
TC
LU LL
P R
L
T1
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