Lull 944E-42 Service Manual - Manual (Page 444)

Hydraulic System
8.192 Model 644E-42/944E-42 Rev. 6/04
a. Frame Sway Joystick Capsule Replacement
1. Lift up the boot (1) and remove the handle
assembly (2) from the pivot mechanism (3).
2. Drive out the pivot pin (4) from the pivot mount (5).
Watch for the washer (6) on the square side of pin.
3. Remove the pivot mechanism (3) from the pivot
mount to access the center capscrew (7). Remove
the capscrew and mount from the valve body (8).
4. Remove the capsule (9) from the valve body (8).
5. Clean all components with a suitable cleaner before
inspection.
6. 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.
7. Assemble new capsule (9), with the o-ring, lightly
oiled, into the cavity in the valve body (8).
8. Reassemble the pivot mount (5) with capscrew (7).
Torque the capscrew to 14 ±1.5 lb-ft (19 ±2 Nm).
9. Place the pivot mechanism (3) in place and
reassemble the pivot pin (4) and washer (6).
10. Reassemble the handle assembly (2) to the pivot
mechanism (3). Torque the handle nut to 10 ±1 lb-ft
(14 ±1,4 Nm).
After replacing a joystick valve assembly, check that all
joystick functions operate correctly.
8.12.8 Auxiliary Hydraulic Pressure Release
Valve (Early Production)
The auxiliary hydraulic pressure release valve is attached
to a bracket which is attached to the pilot select valve at
the top center of the valve plate under the cab.
The auxiliary hydraulic pressure release valve switch is
located on the right front console and when it is activated
it relieves all trapped pressure in the auxiliary hydraulic
lines.
a. Auxiliary Hydraulic Pressure Release Valve
Removal
1. Park the vehicle on a firm, level surface, fully retract
all hydraulic cylinders, ground the attachment (if
any), place the travel select lever in the [N]
NEUTRAL DETENT position, engage the park brake
switch and shut the engine OFF.
2. Place an Accident Prevention Tag on both the
ignition switch and the steering wheel, stating that
the vehicle should not be operated. Refer to Section
1.5, “Accident Prevention Tag Usage.”
3. Unlatch and open the engine cover. Allow the
hydraulic fluid to cool.
4. Remove the access plate from the floor of the cab.
5. Label or otherwise mark the hydraulic hoses (10)
connected to the auxiliary hydraulic pressure release
valve (11). Disconnect and cap all hoses and fittings.
6. Label or mark the wire harness connector attached
to the auxiliary hydraulic pressure release valve (11).
Disconnect electrical connector (12).
7. Remove two capscrews (13) and two washers (14)
from the auxiliary hydraulic pressure release
valve (11) and bracket (15) to remove the valve from
the valve plate (16).
MU4550
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WARNING:
Hot hydraulic fluid can
cause severe burns. Wait for hydraulic fluid to
cool before servicing any hydraulic component.