JLG 4013PS Service Manual - Manual (Page 136)

Hydraulic System
8-26 3508PS, 3509PS, 3512PS, 3513PS, 4008PS, 4009PS, 4012PS, 4013PS, 4017PS, 40.8, 40.9
f. Leveling Valve Installation
1. Install the leveling valve into the engine
compartment and secure with the previously used
hardware.
2. Prime the leveling valve by filling the inlet openings
with fresh, filtered hydraulic oil from a clean
container, before attaching the hoses.
3. Use new oiled o-rings as required. Uncap and
connect all hoses, clamps, etc. to the leveling valve.
4. Check the routing of all hoses, wiring and tubing for
sharp bends or interference with any rotating
members, and install tie wraps and/or protective
conduit as required. Tighten all tube and hose
clamps.
5. Properly connect the battery.
6. Start the engine and run at approximately one-third
to one-half throttle for about one minute without
moving the machine or operating any hydraulic
functions.
7. Inspect for leaks and check the level of the hydraulic
oil in the reservoir. Shut the engine OFF.
8. Wipe up any hydraulic oil spillage in, on, near and
around the machine, work area and tools.
9. Close and secure the engine cover.
10. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
8.10 HYDRAULIC CYLINDERS
8.10.1 General Cylinder Removal
Instructions
1. Remove any attachment from the machine. Park the
machine on a firm, level surface, allowing sufficient
workspace. Level the machine, place the transmission
control lever in (N) NEUTRAL, engage the park brake,
shut the engine OFF and block the wheels.
2. Place a Do Not Operate Tag on both the ignition key
switch and the steering wheel, stating that the
machine should not be operated.
3. Open the engine cover. Allow the system fluids to
cool.
4. Properly disconnect the battery.
5. Relieve any trapped pressure in the hydraulic
system by using the handle or wrench (located in the
toolbox) and move the double nut on the side of the
actuator module on the valve section back and forth.
6. Label, disconnect and cap hydraulic hoses and
cylinder ports in relation to the cylinder.
7. Attach a suitable sling to an appropriate lifting device
to the cylinder. Make sure the device used can
actually support the cylinder.
8. Remove the lock bolt and/or any retaining clips
securing the cylinder pins. Remove the cylinder pins.
9. Remove the cylinder.
10. Wipe up any hydraulic oil spillage in, on, near or
around the machine.
8.10.2 General Cylinder Disassembly
1. Clean the cylinder with a suitable cleaner before
disassembly. Remove all dirt, debris and grease
from the cylinder.
2. Clamp the barrel end of the cylinder in a soft-jawed
vise or other acceptable holding equipment if
possible.
Note: Avoid using excessive force when clamping the
cylinder in a vise. Apply only enough force to hold the
cylinder securely. Excessive force can damage the
cylinder tube.
3. If applicable, remove the counterbalance valve from
the side of the cylinder barrel.
Note: DO NOT tamper with or attempt to adjust the
counterbalance valve cartridge. If adjustment is
necessary, replace the counterbalance valve with a new
part.
4. Extend the rod (5) to allow access to the base of the
cylinder.
Note: Protect the finish on the rod at all times. Damage
to the surface of the rod can cause seal failure.
5. Using a pin spanner wrench, unscrew the head
gland (6) from the barrel (1). A considerable amount
of force will be necessary to remove the head gland.
Carefully slide the head gland down along the rod
toward the rod eye end, away from the cylinder
barrel.
WARNING
Significant pressure may be trapped inside the
cylinder. Exercise caution when removing a
counterbalance valve or a pilot-operated check valve
from a cylinder.