JLG 4017 Service Manual - Manual (Page 105)

8.5 4017
Hydraulic System
b. Adjusting Hydraulic Pressure
There is only one adjustment to set the main hydraulic
pressure.
1. Park the machine on a firm, level surface. Engage
the park brake, place the transmission control lever
in (N) NEUTRAL, level the boom and turn the engine
OFF. Remove the cap on the bottom relief (2) on the
pilot valve at the main hydraulic pump located at the
rear of the engine.
2. Start the machine and loosen the jam nut on the
relief and using an allen wrench; turn the relief
clockwise to increase pressure or counter-clockwise
to decrease pressure. Set the pressure to 250 bar
(3625 psi) +/- 5 bar (70 psi) at full throttle.
3. Tighten the jam nut and recheck the pressure at full
throttle. If the reading is within specification, shut the
machine off, install the safety cap and remove the
gauge from the test port.
4. If the proper pressure cannot be set, refer toSection
8.4.2, “Hydraulic Schematic,” and/or Section 9.5,
“Electrical System Schematics,” to help trouble
shoot and correct the problem.
MZ1270
2
Engine