JLG 723A Service Manual - Manual (Page 48)

Cab and Covers
4-4 L2906H, 2906H, 3507H, 619A, 723A, 29.6LP, 29.6, 35.7
4.4.2 Steering Column/Valve Replacement
a. Steering Column 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 covers. Allow the system fluids to
cool.
4. Properly disconnect the battery.
5. Remove the steering wheel (1) (Refer to Section
4.4.1, “Steering Wheel.”), transmission control lever
(2) and accessory lever (if equipped)(3).
6. Loosen and remove the steering column cover.
7. Loosen and remove the dash cover.
8. Label, disconnect and cap the hydraulic hoses (4)
and fittings on the steering orbitrol valve (5).
9. Remove the four hex-flange capscrews (6)(three if
machine is equipped with tilt column) connecting the
orbitrol valve to the steering column.
10. Pull the steering column assembly and orbitrol valve
from the machine cab.
Note: DO NOT disassemble the steering orbitrol valve.
The steering orbitrol valve is not serviceable and must
be replaced in its entirety, if defective.
b. Steering Column and Valve Installation
1. Install the four hex-flange capscrews (three if
machine is equipped with tilt column) through the
steering column, mounting bracket and into the top of
the orbitrol valve.
Note: ALWAYS use new o-rings when servicing the
machine.
2. Uncap and if needed, install new o-rings into the
fittings. Lubricate the o-rings with clean hydraulic oil.
3. Uncap and reconnect the previously labeled
hydraulic hoses to their appropriate locations.
4. Install the dash cover.
5. Install the steering column cover.
6. Install the steering wheel (Refer to Section 4.4.1,
“Steering Wheel.”), accessory lever and
transmission control lever.
7. Properly connect the battery.
8. Start the engine and check the operation of all
controls. Check for oil leaks. Check the hydraulic oil
level in the tank and add oil as required.
9. Clean up all debris, hydraulic oil, etc., in, on, near
and around the machine.
10. Close and secure the engine covers.
11. Remove the Do Not Operate Tags from both the
ignition key switch and the steering wheel.
c. Power Steering Test
Conduct a pressure check of the steering hydraulic
circuits at the test port on the implement pump. Refer to
Section 8.6.6, “Steering Pressure Checking.”
4.4.3 Brake Pedal and Valve
a. Brake Valve Removal
Refer to Section 8.11.2, a. “Service Brake Valve
Removal,” for removal information.
b. Brake Valve Installation
Refer to Section 8.11.2, b. “Service Brake Valve
Installation,” for installation information.
c. Service Brake Pedal 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.
MY2440
1
2
3
5
4
6