EMERGENCY JACK RETRACTION
(Filename: MI150000A.DOC
| Revised: 30JAN16)
|
Unless a jack is seriously damaged, most jacks can be
retracted simply by opening the manual valve release for each of the jacks.
This includes spring-retract (single-acting) jacks and power-retract jacks
(double-acting jacks without springs). Spring-retract jacks should retract by themselves when the
valves are opened. If the springs are missing or the jack does not retract,
the jack can usually be pried up using a bar, board or shovel. Power retract
jacks will have to be pried up after the valves have been opened. Locate the hydraulic control unit. If the pump runs, you can operate the system
so you can use the sound of the pump to locate the control unit. The park
brake (if so equipped) must be set to use the pump. The ignition must be on
or for towable units, there may be a master power switch that must be on.
Locate the HWH Leveling System control panel. If the top left button has an
“I” or “HYD” on it, push the button one time. When the light above the button
is on, the manual arrows on the right side of the panel will function. If the
top left button has a symbol instead of an “I” or “HYD”, the manual arrows
will function with the ignition or master power switch on. Push any of the
“UP” arrow buttons to run the pump so you can locate the control unit. The
control unit can be mounted in a compartment, behind the front grill, or
mounted to the frame of the vehicle under the vehicle. The solenoid valves on
the control unit should be accessible without crawling under the vehicle. WARNING: DO NOT
CRAWL UNDER ANY VEHICLE SUPPORTED ON THE LEVELING JACKS WITHOUT PROPERLY
SUPPORTING THE FRAME OF THE VEHICLE SO IT CANNOT DROP. WHEN THE FLUID IS
RELEASED FROM A JACK THE VEHICLE MAY DROP AND/OR MOVE FORWARD OR BACKWARD
CAUSING INJURY OR DEATH. Make sure people and objects are clear of the vehicle
before opening valves. Allow clearance for the vehicle to lower. Open
solenoid valves slowly so the vehicle drops slowly as the fluid is released. If all of the
jacks must be retracted, proceed to the appropriate instructions for “MOTORIZED
VEHICLES” or “NON-MOTORIZED VEHICLES”. If individual
jacks need to be retracted, refer to the “HYDRAULIC CONTROL UNIT
ARRANGEMENTS” later in this section for valve locations. Refer to “VALVE IDENTIFICATION AND OPERATION”
located later in this section to help identify the valves you are dealing
with so they can be opened and closed properly. |
MOTORIZED VEHICLES
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Motorized Vehicles Standard Control Unit Spring-Retract Jacks The two center valves control the front jacks. Slowly open
the two center valves. When the weight is off the front jacks, open the two
outer valves. When the jacks are fully retracted, the vehicle can be moved.
If necessary, pry the jacks up. It is
recommended to leave the valves open until the coach has been delivered to
the repair site. This type of hydraulic control unit has a shuttle valve.
If none of the jacks will retract after the valves have been opened manually,
there is most likely a shuttle valve problem. Click here, MI15.8813, for a detailed
explanation and diagram to retract jacks if there is a shuttle valve issue. If a jack will not retract no matter what is tried, the
cylinder may have to be removed. The vehicle may have to be lifted to remove
a cylinder. It may be possible due to a hose issue, the jack will retract
when the hose is removed. Motorized Vehicles With Two Solenoid Valves for each
Jack With or Without Auxiliary Hand Pump These control units have a manifold that is labeled with
the valve location for each jack or function and which is the extend or
retract valve. Slowly open the appropriate valves to retract the two front
jacks. Although the power retract style jack will have to be
pried up if the system does not have an auxiliary hand pump, the vehicle will
still lower when the valve is opened until weight is off the jack. When the
weight is off the front jacks, the valves for the rear jacks can be opened. If the control unit is equipped with an auxiliary hand
pump, click here MP34.9904
for detailed instructions on the use of the hand pump. For power retract
jacks, when the weight is off the jacks, it may be easier to use the hand
pump to retract one jack at a time. If the hand pump will not function it may
need to be primed, click here MP44.0009
for detailed priming instructions. If the hand pump still does not function,
the jack(s) will have to be pried up or removed. It is recommended to leave the valves open until the coach has been
delivered to the repair site. . If a jack will not retract no matter what is tried, the
cylinder may have to be removed. The vehicle may have to be lifted to remove
a cylinder. It may be possible due to a hose issue, a jack will retract when
the hose is removed. |
NON-MOTORIZED VEHICLES
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Non-Motorized
Vehicles Standard
Control Unit With or
Without Lock/Equalize Valve Spring-Retract
Jacks Do not retract the
front jacks unless the trailer can be hitched to a tow vehicle at this time
or the front of the trailer can be safely supported by alternate landing
gear, jack stands or blocks. Slowly open the two outer solenoid valves to retract the
rear jacks. If the control unit has the lock/equalize valve, the valves are
in a different location. Refer to “Standard
Hydraulic Control Unit With Lock/Equalize Valve”. When the weight is
off the rear jacks, the front jacks can be retracted. Hitch the trailer to
the tow vehicle during this process or support the front of the trailer with
alternate landing gear or stands. Slowly open the appropriate valves to
retract the front jacks. If necessary, pry the jacks up. It is recommended to leave the valves open until the coach has been
delivered to the repair site. This type of hydraulic control unit has a shuttle valve.
If none of the jacks will retract after the valves have been opened manually,
there is most likely a shuttle valve problem. Click here, MI15.8813, for a detailed
explanation and diagram to retract jacks if there is a shuttle valve issue. If a jack will not retract no matter what is tried, the
cylinder may have to be removed. The vehicle may have to be lifted to remove
a cylinder. It may be possible due to a hose issue, the jack will retract
when the hose is removed. Non-Motorized Vehicles With Two Solenoid Valves for Each
Jack With or Without Auxiliary Hand Pump The auxiliary hand pump cannot be used to help retract
spring-retract jacks. These
control units have a manifold that is labeled with the valve location for
each jack or function and which is the extend or retract valve. Do
not retract the front jacks unless the trailer can be hitched to a tow
vehicle at this time or the front of the trailer can be safely supported by
alternate landing gear, jack stands or blocks. Some vehicles will have a
remote manifold with two valves per jack for the front or rear jacks. The
remote manifold may be located near the hydraulic control unit or near the
jacks it controls. Slowly open the appropriate solenoid valves to retract the
rear jacks. Although the power retract style jack will have to be pried up if
the system does not have an auxiliary hand pump, the vehicle will still lower
when the valve is opened until weight is off the jack. If the control unit is
equipped with an auxiliary hand pump, click here MP34.9904 for detailed
instructions on the use of the hand pump. For power retract jacks, when the
weight is off the jacks, it may be easier to use the hand pump to retract one
jack at a time. If the hand pump will not function it may need to be primed,
click here MP44.0009 for
detailed priming instructions. If the hand pump still does not function, the
jack(s) will have to be pried up or removed. When the weight is off the rear
jacks, the front jacks can be retracted. Hitch the trailer to the tow vehicle
during this process or support the front of the trailer with alternate
landing gear or stands. Slowly open the appropriate valves to retract the
front jacks. If necessary, pry the jacks up. It is recommended to leave the valves open until the coach has been
delivered to the repair site. |
