Lull 944E-42 Service Manual - Manual (Page 142)

Hydraulic System
8-26 944E-42
c. Single Joystick Pilot Select Valve Installation
1. Position the pilot select valve back onto the valve
plate. Install and tighten the two capscrews.
2. Uncap and reconnect the previously labeled
hydraulic hoses.
3. Reconnect any electrical connections to the
appropriate locations.
4. Properly connect the batteries.
5. Start the machine and run at approximately one-third
to one-half throttle for about one minute without
moving the machine or operating any hydraulic
function.
6. Inspect the pilot select valve for leaks and check the
level of the hydraulic fluid in the reservoir. Shut the
engine OFF.
7. Wipe up any hydraulic fluid spillage in, on, near and
around the machine, work area and tools.
8. Reinstall the access plate and side access panel to
the cab.
9. Close and secure the engine cover.
d. Single Joystick Pilot Select Valve Test
Conduct a pressure check of the joystick circuit. Refer to
Section 8.3.1, “Pressure Checks and Adjustments.”
8.7.7 Frame Sway Joystick Valve
The frame sway joystick (6) controls the frame sway only
and is only pilot operated. If the frame sway is not
functioning properly, check the electrical circuits of the
Stabil-TRAK system to ensure proper electrical operation
before considering replacement of this joystick.
Verify the correct operation of the joystick before
considering replacement of the joystick valve. The
capsules are the only serviceable components within the
joysticks. The joystick must be replaced in their entirety if
replacement is necessary. Refer to Section 4.3.6,
“Joystick Assemblies.”
a. Frame Sway Joystick Capsule Replacement
1. Lift up boot (7) and remove the handle assembly (8)
from the pivot mechanism (9).
2. Drive out pivot pin (10) from the pivot mount (11).
Watch for the washer (12) on the square side of the
pin.
3. Remove the pivot mechanism (9) to access the
capscrew (13). Remove the capscrew and mount
from the valve body (14).
4. Remove the capsule (15) from the valve body.
5. Clean all components with a suitable cleaner before
inspection.
6. Inspect internal passageways of the valve body 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 valve body.
7. Assemble the new capsule (15) with the lightly oiled
o-ring into the valve body.
8. Reassemble the pivot mount with capscrew. Place
the pivot mechanism in place and reassemble the
pivot pin and washer.
9. Reassemble the handle assembly to the pivot
mechanism
After replacing a joystick valve assembly, check that all
joystick functions operate correctly.
8.7.8 Auxiliary Hydraulic Pressure Release
Valve
The auxiliary hydraulic pressure release valve is attached
to the right side of the valve plate under the cab.
The auxiliary hydraulic pressure release valve switch is
located on the right console and when activated it
relieves all trapped pressure in the auxiliary hydraulic
circuit.
MU6411
6
MU4551
7
8 10
11
12
9
13
14
15