JLG 600SC_660SJC Service Manual - Manual (Page 273)

SECTION 8 - HYDRAULICS
3121157 – JLG Lift – 8-13
8.7 PRESSURE SETTING PROCEDURES
Cold temperatures have a significant impact on pressure
readings. JLG Industries Inc. recommends operating the
machine until the hydraulic system has warmed to normal
operating temperatures prior to checking pressures. JLG
Industries Inc. also recommends the use of a calibrated
gauge. Pressure readings are acceptable if they are within
± 5% of specified pressures.
Main Relief
1. Install pressure gauge at quick disconnect on port
MP on main valve.
2. With the aid of an assistant, activate telescope in.
3. While monitoring pressure gauge, adjust main relief
to 3000 PSI (206.85 Bar). Turn the adjuster clock-
wise to increase pressure or counterclockwise to
decrease pressure.
Lift Down
1. Install pressure gauge at quick disconnect on port
MP on main valve.
2. With the aid of an assistant, activate lift down.
3. While monitoring pressure gauge, adjust the lift
down relief to 1500 PSI (103 Bar). Turn the adjuster
clockwise to increase pressure or counterclockwise
to decrease pressure.
Swing
NOTE: Left and right swing pressures are set with one
adjustment.
1. Install pressure gauge at quick disconnect on port
MP on main valve.
2. Lock the turntable using the turntable lock.
3. With the aid of an assistant, activate swing left or
right
4. While monitoring pressure gauge, adjust the swing
relief to 1700 PSI (117 Bar). Turn the adjuster clock-
wise to increase pressure or counterclockwise to
decrease pressure.
Platform Level Up
PRESSURE IS TRAPPED AT PORT M3.
1. Install pressure gauge at quick disconnect on port
M3 on main valve after releasing the pressure. To
release the pressure, activate level down to the end
of the stroke. This will release the pressure and allow
installation of a pressure gauge.
2. With the aid of an assistant, activate level up.
3. While monitoring pressure gauge, adjust the level
up relief to 2800 PSI (193 Bar). Turn the adjuster
clockwise to increase pressure or counterclockwise
to decrease pressure.
Platform Level Down
PRESSURE IS TRAPPED AT PORT M4.
1. Install pressure gauge at quick disconnect on port
M4 on main valve after releasing the pressure. To
release the pressure, activate level up to the end of
the stroke. This will release the pressure and allow
installation of a pressure gauge.
2. With the aid of an assistant, activate level down.
3. While monitoring pressure gauge, adjust the level
up relief to 1800 PSI (124 Bar). Turn the adjuster
clockwise to increase pressure or counterclockwise
to decrease pressure.
Jib Up
1. Install pressure gauge on the M port on the jib block.
2. With the aid of an assistant, activate jib up.
3. While monitoring pressure gauge, adjust the jib up
relief to 1500 PSI (103 Bar). Turn the adjuster clock-
wise to increase pressure or counterclockwise to
decrease pressure.
Jib Down
1. Install pressure gauge on the M port on the jib block.
2. With the aid of an assistant, activate jib down.
3. While monitoring pressure gauge, adjust the jib
down relief to 1200 PSI (82 Bar). Turn the adjuster
clockwise to increase pressure or counterclockwise
to decrease pressure.