JLG M450 ANSI Service Manual - Manual (Page 173)

SECTION 5 - HYDRAULICS
3121127 – JLG Lift – 5-21
Platform Level Down 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 Down.
On machines S/N 0300062642 to present, install the
pressure gauge at the "B1" port on the back of the
Main Control Valve, activate and bottom out Platform
Level Down.
2. Adjust Platform Level Down 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.
Steer Relief
1. With pressure gauge at “G” port on steer/brake
valve, activate and bottom out Steer Left or Right.
2. Adjust Steer Relief to value given in Table 5-4, Pres-
sure Settings - Prior to S/N 0300062642 or Table 5-5,
Pressure Settings - S/N 0300062642 to Present.
3. Shut down hydraulic system and remove pressure
gauge.
Jib Lift (Up and Down) Relief
1. Install the pressure gauge at the at the "G" port on
the Main Control valve, activate and bottom out jib
up or down.
2. Adjust the Jib LIft pressure to the value given in
Table 5-4, Pressure Settings - Prior to S/N
0300062642 or Table 5-5, Pressure Settings - S/N
0300062642 to Present.
Releveling Valve Relief
1. Install a pressure gauge at port "G" on the main
valve.
2. Adjust the lower lift down pressure relief to the value
given in Table 5-4, Pressure Settings - Prior to S/N
0300062642 or Table 5-5, Pressure Settings - S/N
0300062642 to Present.
3. With the lower boom lowered all the way, pull the red
releveling knob and activate lower lift down.
4. Adjust the releveling pressure relief to the value
given in Table 5-4, Pressure Settings - Prior to S/N
0300062642 or Table 5-5, Pressure Settings - S/N
0300062642 to Present. Turning clockwise increases
the pressure and turning counterclockwise
decreases pressure. The relief valve is located
directly below the red releveling knob.
LC LR
TR
T2
B2
B1
S2
S1
R2 R1
TC
LU LL
P R
L
T1
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