JLG 4394RT Service Manual - Manual (Page 142)

SECTION 4 - HYDRAULICS
4-18 – JLG Lift – 3121133
4.13 DIRECTIONAL VALVE
Pressure Setting Procedure
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.
1. Activate engine and allow hydraulic system to come
up to operating temperature.
2. Install pressure gauge at quick connect on main
valve (M1).
3. Energize and bottom ut the leveling jack function.
Adjust relief to 2800 psi (193 bar).
4. De-energize jack function and shut down engine.
Remove pressure gauge.
PA1
PA3
PA4
PA2
PB1
PB2
PB4
PB3
LP
T
PA
1
PA
3
PA
4
PA
2
PB
1
PB2 PB
4
PB3
LP T
Figure 4-21. Directional Valve
item Torque
PA1
40 ft-lbs
(54 Nm)
PB1
23 ft-lbs
(31 Nm)