Power Gear Leveling Jacks

[cortés]

Schu's News - Article

Dave Schumann
General Manager, Customer Relations Group
Airstream, Inc.

I hope everyone is getting ready for the Holidays; it’s a time for family
and friends to get together and share life’s blessings.
From the Airstream family we wish you a happy and safe holiday season.

Here are some hints on care and trouble shooting Power Gear leveling jacks.
This a general guide line and may not apply to all systems.

Power Gear Leveling Jacks

Although the Power Gear leveling system is normally very
reliable, your jacks are exposed to weather, dirt and grime that
make them prone to problems. Like any mechanical/electrical
system, it is likely that you will eventually experience some
problems with your jacks. These tips will hopefully help you
fix your problem yourself, or at least save you money if you
have someone else repair your jacks.

The Power Gear manual leveling system is a hydraulic
system based on the following components:

• Control panel located in the cockpit on the driver’s side.

• An electric pump for the hydraulic fluid.

• Four solenoid valves that control the hydraulic fluid.

• Hydraulic fluid Reservoir.

• The hydraulic jacks themselves

Your motorhome has four jacks. However, the two jacks
in front are hydraulically connected together. Three of the
solenoid control valves control hydraulic fluid TO the jacks
(for jack lowering) and the fourth solenoid is the dump
solenoid that allows the hydraulic fluid to return to the
reservoir so the jacks can retract. Although your jack control
pad has four buttons, you cannot control each jack independently.

The REAR button lowers both rear jacks simultaneously.

The FRONT button lowers both front jacks simultaneously.

The LEFT button raises the left rear and left front jacks simultaneously.

The RIGHT button raises the right rear and right front jacks simultaneously.

So, leveling your coach
is somewhat akin to leveling a three-legged stool.
In a properly operating system, here is what happens when
you use your jacks:

[1] When you turn on the power to your jacks, 12v is applied
to the control solenoids.

[2] When you push one of the jack buttons, the 12v hydraulic
pump is turned on and GROUND is applied to the appropriate
solenoid, causing it to open and send hydraulic fluid
to the jack, lowering the jack. When you release your
finger from the jack button, ground is removed from the
solenoid and the solenoid closes, which closes this hydraulic
line.

[3] When you retract the jacks, the dump solenoid is actuated
which allows the hydraulic fluid from ALL the jacks to be
returned to the hydraulic fluid reservoir, and the springs
on the jacks pull them up and forcing the hydraulic fluid
back to the reservoir.

Most problems are either a failure of the jacks to retract,
or the “Jacks Down� alarm will not go off. Another less
common failure is that the jacks will not go down.
“Jacks Down� Alarm Stays On The Power Gear
system monitors the hydraulic fluid level in the reservoir to
determine if the jacks have been retracted. The most
common problem - and the easiest to fix - is an incorrect
hydraulic fluid level. You can also look at your jacks to
determine if they are retracted - if your jacks are retracted
and the “Jacks Down� alarm is on, then you most likely have
a low hydraulic fluid level. It is absolutely necessary that you
only check your hydraulic fluid when the jacks are RETRACTED.

When you open the cap on your hydraulic fluid
reservoir, you will notice that it has a dipstick attached to it.
For a round reservoir, the fluid should be 1/8" from the bottom
of the dipstick and for a square tank; it should be 7/8" from the
bottom. Be very careful not to overfill the reservoir.
If low hydraulic fluid was the cause of your problem, you
need to inspect your jacks and hoses for a leak. Most likely,
the seal on one of your jacks has developed a slow leak. If
you have a leaking jack, the most cost-effective solution is to
remove the jack and take it to a place that repairs hydraulic
jacks.

If your jacks still will not retract, your solenoid dump valve
is probably not working. This could be a bad solenoid (a
problem mostly with late 1997 and all 1998 coaches) or it
could just be a bad ground. With your volt-ohm meter or
electrical tester, you will find that one lead on the solenoid will
have 12v on it. The other lead is the ground lead. Try a new
ground lead, as this is mostly likely the problem. With 12v on
one terminal and a good ground on the other terminal of the
dump solenoid, your jacks will retract if the solenoid is good.
If the solenoid is bad, the jacks will still not retract. In this
case, the solution gets messy as you can disconnect the
hydraulic hose forward of the dump valve to retract the jacks.

Maintenance It is recommended that you (at least)
monthly wipe down your jack shafts (with the jacks extended,
the shiny surface) and lubricate the shiny surface with a
lubricant that will not attract dirt. Also, it is a good idea to use
some “jack blocks�. This serves two purposes. First, it will
give your jacks a solid footing so that they will not sink into
loose or wet soil, getting the jack arms dirty. Also, it will
minimize the jack travel required to level your coach.

Before you retract your jacks, it is also a good idea to
inspect the inside of the jack pads for dirt and rocks. Rocks
are especially dangerous - at least one owner suspects that a
loose rock from his jack pad was responsible for a hole in his
radiator.

Really?

Sign on a Lockhart, Texas, gas station and mini-mart:
We’re out of Rolaids, but we’ve got gas.

An auto mechanic received a repair order that read,
“Check for clunking sound when going around corners.�
Taking the car out for a test drive, he made a right turn, and
a moment later he heard a clunk. He then made a left turn and
again heard a clunk.
Back at the shop, he opened the car’s trunk, and soon
discovered the problem.
Promptly he returned the repair order to the service
manager with this notation: “Remove bowling ball from
trunk�.

Have a great month and see you on down the road!