Lull 944E-42 Service Manual - Manual (Page 138)

Hydraulic System
8-22 944E-42
9. 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.
10. Inspect for leaks and check the level of the hydraulic
fluid in the reservoir. Shut the engine OFF.
Note: Check for leaks and repair as required before
continuing. Add hydraulic fluid to the reservoir as needed.
11. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
12. Install the transmission covers.
13. Close and secure the rear door.
g. Main Control Valve Test
Conduct a pressure check of the hydraulic system in its
entirety. Adjust pressure(s) as required. Refer to Section
8.3.1, “Pressure Checks and Adjustments.”
8.7.3 Joystick Valve (Dual Joystick)
The individual joystick valves are mounted on the right
side console in the cab. The front joystick (6) has an
electric circuit in it to control the auxiliary hydraulic
functions.Verify that the electrical solenoids on the pilot
select valve are functioning properly before considering
replacement of the front joystick. Refer to Section 9.5.2,
“944E-42 Electrical Schematics.”
The rear joystick (7) has no electrical connections and is
only pilot operated. If this joystick is not functioning
properly, the joystick must be replaced.
Verify the correct operation of the joysticks before
considering replacement of the joystick valve. The
capsules for individual joysticks are the only serviceable
component within the individual joysticks. The joysticks
must be replaced in their entirety if replacement is
necessary. Refer to Section 4.3.6, “Joystick Assemblies.”
a. Front and Rear Joystick Capsule Replacement
1. Lift up boot (8) and remove the handle (9) from the
joystick joint assembly.
2. Remove the joint assembly (10) from the valve body
(11).
3. Remove the capsule (12) from the valve body (11).
4. Clean all components with a suitable cleaner before
inspection.
5. Inspect internal passageways of the pilot select
valve and it’s component parts for wear, damage,
etc. If inner surfaces of the pilot select valve DO NOT
display an ultra-smooth, polished finish, or
components are damaged in any way, replace the
pilot select valve or appropriate part. Often, dirty
hydraulic fluid causes failure of internal seals and
damage to the polished surfaces within the pilot
select valve.
6. Assemble the new capsule assembly (12), with the
lightly oiled o-ring, into the valve body (11).
7. Reassemble the joint assembly (10) to the valve
body (11). Torque the four capscrews to (14) to
7 ± 1 lb-ft (9,5 ± 1,4 Nm).
8. Reassemble the handle (9) and the boot (8) to the
joint assembly. Use a punch in the hole on the joint
assembly to hold it in place while tightening the
handle assembly. Torque the handle assembly to
33 ± 3.5 lb-ft (44,7 ± 4,7 Nm).
After replacing a joystick valve assembly, check for
proper function of all joystick functions.
OU0411
6
7
MU3891
9
8
10
12
14
11