Lull 944E-42 Service Manual - Manual (Page 437)

8.185 Model 644E-42/944E-42 Rev. 6/04
Hydraulic System
8.12.3 Joystick Valve (Dual Joystick)
The individual joystick valves are mounted on the right
side console in the cab. The front joystick (10) has an
electrical 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 9.8.29,
“Dual Joystick - Auxiliary Hydraulic Circuit &
Troubleshooting.”
The rear joystick (11) 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 the individual joysticks are the only
serviceable components within the individual
joysticks.The joysticks must be replaced in their entirety
if replacement is necessary. Refer to Section 4.3.8,
“Front, Rear and Frame Sway Joystick Assembly
Replacement.”
a. Front and Rear Joystick Capsule Replacement
1. Lift up the boot (12) and remove the handle (13)
from the joystick joint assembly (14). Refer to
Section 9.14.10, “Dual Joystick,” to remove the
handle.
2. Remove the joint assembly (14) from the valve
body (15).
3. Remove the capsule (16) from the valve body (15).
4. Clean all components with a suitable cleaner before
inspection.
5. Inspect internal passageways of the pilot select
valve and its 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 (16), with the
o-ring lightly oiled, into the valve body (15).
7. Reassemble the joint assembly (14) to the valve
body (15). Torque the four capscrews (17) to
7 ±1 lb-ft (9,5 ±1,4 Nm).
8. Reassemble the handle (13) and the boot (12) to the
joint assembly (14). Use a punch in the hole (18) 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 the
proper functioning of all joystick functions.
OU0410
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11
MU3890
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15
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