JLG 4013PS Service Manual - Manual (Page 133)

8-23 3508PS, 3509PS, 3512PS, 3513PS, 4008PS, 4009PS, 4012PS, 4013PS, 4017PS, 40.8, 40.9
Hydraulic System
Note: ALWAYS replace seals, o-rings, gaskets, etc.,
with new parts to help ensure proper sealing and
operation. Lubricate seals and o-rings with clean
hydraulic oil.
3. Use new oiled o-rings as required. Reattach and
secure all valves, hoses, clamps, etc.
4. Check the routing of all hoses, 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. Bleed air from the brake circuit. Refer to Section
8.9.3, “Brake Test.”
8. Inspect the service brake valve and connections for
leaks, and check the level of the hydraulic oil in the
reservoir. Shut the engine OFF.
Note: Check for leaks, and repair as required before
continuing. Add hydraulic oil to the reservoir as needed.
9. Close and secure the engine cover.
10. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
8.9.3 Brake Test
Carefully bleed the brake lines as soon as the brake valve
is installed in the machine. Air in the system will not allow
the brakes to apply properly. Work with an assistant to
perform this procedure.
Note: 17M machines have an extra set of bleeders on
the front axle. The outside set is for the park brakes and
the inside set is for the service brakes. Be sure to bleed
the correct circuit.
1. Place the transmission control lever in (N)
NEUTRAL, engage the park brake, and start the
engine.
2. Remove the plastic cap from the front brake bleeder.
Attach one end of a length of transparent tubing over
the brake bleeder. Place the other end of this tubing
in a suitable transparent container that is partially
filled with hydraulic oil. The end of the tubing must
be below the oil level in the container.
3. DO NOT open the brake bleeder without holding the
tubing firmly on the bleeder. There is a pressure at
the brakes. Carefully open the bleeder with a
wrench. Have the assistant depress the brake pedal.
Close the brake bleeder when air bubbles no longer
appear in the oil. Release the brake pedal. remove
the tubing from the brake bleeder.
4. Repeat Steps 2 and 3 for the remaining brake
bleeders.
5. Install a vacuum pump on the brake reservoir and
remove the remainder of the trapped air from the
brake system.
6. Check brake fluid level and add if necessary using
ATF fluid.
7. Conduct a pressure and function check of the
service brake. Refer to Section 8.3, “Hydraulic
Pressure Diagnosis.”
8.9.4 Steering Orbitrol Valve
Refer to Section 4.3.1, “Steering Column and Orbitrol
Valve,” for details.
8.9.5 Steer Select Valve
The machine can be used in the front-wheel, four-wheel
or crab steering mode. The steer select valve controls the
direction of hydraulic oil flow to the steering cylinder
mounted on each axle. The steer select valve is attached
to a mounting plate inside the frame near the left front
corner of the cab.
Verify the correct operation of the steer select valve
solenoids before considering replacement of the valve.
The housing of the steer select valve is not serviceable
and must be replaced if defective.
a. Steer Select Manifold and Valve Removal
1. Park the machine on a firm, level surface, fully
retract the boom, lower the boom, place the
transmission control lever in (N) NEUTRAL, engage
the park brake and shut the engine OFF.
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. Label, disconnect and cap all hydraulic hoses and
fittings connected to the steering select valve.
6. Disconnect all wire terminal leads attached to the
steering select valve.