JLG 4017PS Service Manual - Manual (Page 150)

Hydraulic System
8-18 3706PS, 3707PS, 4014PS, 4017PS, 33.7, 37.6, 37.7
b. Service Brake Valve Installation
1. Install the service brake valve to its original
orientation in the cab. Secure with the previously
used hardware.
2. Install the service brake pedal linkage to the valve
rod.
3. Uncap and connect the previously labeled hydraulic
hoses to the service brake valve.
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. Inspect the service brake valve and connections for
leaks, and check the level of the hydraulic fluid in the
reservoir. Shut the engine OFF.
8. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
9. Install the lower dash panel in the cab.
10. Install the protective cover to the front of the cab.
11. Close and secure the engine cover.
12. Remove the Do Not Operate Tag from the ignition
key switch and the steering wheel.
8.10.4 Service Brake Bleeding
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. There are two brake bleeder
locations on the front axle. Work with an assistant to
perform this procedure.
1. Place the travel select lever in (N) NEUTRAL,
engage the park brake, and start the engine.
2. Remove the plastic cap from the left brake bleeder
(2). 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 pressure at the
brakes. Carefully open the bleeder. 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 right brake bleeder.
8.10.5 Service Brake Test
1. Install a digital or a 70 bar (1000 psi) gauge to the
test port on the brake valve (behind the front cover of
the cab).
2. Start the machine and apply pressure to the service
brake pedal. A maximum pressure of 44 bar
(638 psi) should be achieved.
3. If further testing is required, refer to Section 8.5.1,
“Hydraulic Pressures.”
8.10.6 Steering Orbitrol Valve
The steering orbitrol valve (3) is located at the base of the
steering wheel shaft, concealed by the lower dash cover.
The valve is not serviceable and must be replaced in its
entirety if defective. For detailed information refer to
Section 4.3.2, “Steering Column/Orbitrol Valve.”
MAM0210
2 2
MZ0370
3