Lull 944E-42 Service Manual User Manual
Page 414
Hydraulic System
8.162
Model 644E-42/944E-42
Rev. 6/04
a. Male Coupler Pressurized (page 8.130 or
With the Trigger Button held down on the Single
Joystick, and the joystick moved to the LEFT,
pilot pressure from the joystick from the
Accumulator Charge/Secondary Function Valve
“PIL” Port to the Single Joystick Pilot Select Valve Port P
and Joystick “P” Port, exiting Port “1” through the Single
Joystick Pilot Select Valve Port “P1”, exiting Port “AUX2”
will shift the auxiliary spool, allowing system pressure to
flow from the auxiliary spool to the MALE connection of
the Auxiliary Hydraulics Coupler. From the coupler, fluid
flows to the attachment, back to the FEMALE Auxiliary
Coupler, to the auxiliary spool on the Main Control Valve,
exiting through the “Outlet” Port to the Oil Cooler, to the
Return Filter and then to the Hydraulic Reservoir.
b. Female Coupler Pressurized (page 8.138 or
With the Trigger Button held down on the Single
Joystick, and the joystick moved to the RIGHT,
pilot pressure from the joystick from the
Accumulator Charge/Secondary Function Valve
“PIL” Port to the Single Joystick Pilot Select Valve Port P
and Joystick “P” Port, exiting Port “2” through the Single
Joystick Pilot Select Valve Port “P2”, exiting Port “AUX1”
will shift the auxiliary spool, allowing system pressure to
flow from the auxiliary spool to the FEMALE connection
of the Auxiliary Hydraulics Coupler. From the coupler,
fluid flows to the attachment, back to the MALE Auxiliary
Coupler, to the auxiliary spool on the Main Control Valve,
exiting through the “Outlet” Port to the Oil Cooler, to the
Return Filter and then to the Hydraulic Reservoir.
8.8.63
Auxiliary Hydraulic Pressure Release
Valve (644E-42, SN 20118 & Before,
SN 0160002519 thru 0160003108)
(944E-42, SN 20123 & Before,
SN 0160002514 thru 0160003106)
The Auxiliary Hydraulic Pressure Release Valve
(page 8.142) is located on the valve plate below
the operator’s cab. The switch to activate the
valve is located in the upper bank of switches on
the right side of the dash. This switch (1) is used to
release pressure in the auxiliary hydraulic system before
connecting or disconnecting the Auxiliary Hydraulic
Couplings.
a. Auxiliary Hydraulic Pressure Release Switch
(Dual Joystick page 8.142)
When the Auxiliary Hydraulic Pressure Release Switch is
pressed for two seconds, the Auxiliary Hydraulic
Pressure Release Valve is opened by a solenoid shifting
the spool in the valve. A Shuttle Valve allows the higher
pressure to be released but it does not allow the oil to
pass into the opposite auxiliary hydraulic hose. The
return oil now can drain directly to the Hydraulic
Reservoir.
The two auxiliary hydraulic couplings can now be easily
connected or disconnected.
b. Auxiliary Hydraulic Pressure Release Switch
(Single Joystick page 8.144)
When the Auxiliary Hydraulic Pressure Release Switch is
pressed for two seconds, the Auxiliary Hydraulic
Pressure Release Valve is opened by a solenoid shifting
the spool in the valve. A Shuttle Valve allows the higher
pressure to be released but it does not allow the oil to
pass into the opposite auxiliary hydraulic hose. The
return oil now can drain directly to the Hydraulic
Reservoir.
The two auxiliary hydraulic couplings can now be easily
connected or disconnected.
MU0070
MU0080
MU5600
OU0501
1