Lull 944E-42 Service Manual - Manual (Page 438)

Hydraulic System
8.186 Model 644E-42/944E-42 Rev. 6/04
8.12.4 Pilot Select Valve (Dual Joystick)
Pilot pressure from the front joystick flows to the pilot
select valve (1). The pilot pressure is then directed to the
auxiliary hydraulic section of the main control valve or to
the transfer carriage section of the main control valve.
The direction of the flow is controlled by the two solenoid
cartridges (3) on the valve. The solenoid cartridges (3)
are controlled by the push button on the top of the
joystick.
The pilot select valve (1) is located on the valve plate (2)
which is located under the cab floor.
a. Pilot Select 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 in
relation to the pilot select valve (1). Disconnect and
cap all hoses and fittings. Label or mark any wire
harness connectors as they relate to the pilot select
valve.
6. Remove the two capscrews (4) holding the pilot
select valve (5) to the valve plate. Remove the pilot
select valve from the valve plate.
b. Pilot Select Valve Disassembly, Inspection and
Reassembly
Note: Use new oiled o-rings as required. ALWAYS
replace seals, o-rings, gaskets, etc., with new parts to
help ensure proper sealing and operation. Lubricate
seals and o-rings with clean hydraulic oil.
Note: Torque all the fittings as specified in Section 2.3,
“Torques.”
1. Remove the elbow fittings (6) from the “A3” and “B1”
ports on one side of the block (7) and from the “P1”
and “P2” ports on the other side.
2. Remove the straight fittings (8) from the “A1” and
“B3” ports on one side of the block.
3. Remove the two solenoid cartridges (9) from the
block.
WARNING:
Hot hydraulic fluid can
cause severe burns. Wait for hydraulic fluid to
cool before servicing any hydraulic component.
MU4020
1
2
3
MU4030
4
5