Air suspension upgrades

[scott shean]

J R, I recently replaced the exhaust solenoids and rebuilt
the "hold" solenoids on my EL II system. The cost was about
$160 for parts. The system now holds air for weeks. BTW,
the manual states that the exhaust solenoid will limit air
pressure to 150-180 psi.

Incidentally, as far as I know, all of the hold solenoids
are installed backwards from the factory. Even the manual
is incorrect about their installation. (At least they were
consistent.) The solenoid valve has an arrow on the side of
the body, which should point in the direction that you want
the solenoid to "hold". In our application, we want to
"hold" air in the bag. Therefore, the arrow should point
away from the bag and toward the compressor. If yours are
still in the original configuration, the arrow will be
pointing toward the bag, and you can get a nice improvement
in leak-down by reversing their direction.

Scott Shean
Baton Rouge, LA
78 Royale

>-----Original Message-----
>From: owner-gmcmotorhome
>[mailtowner-gmcmotorhome]On Behalf Of
>Jrwheeler7
>Sent: Wednesday, September 22, 1999 9:17 AM
>To: gmcmotorhome
>Subject: GMC: Air suspension upgrades
>
>
>Scott,
>
>I failed to mention it in my post, but the upgrade is for
the
>Electro Level
>II for my coach. I have leakdown in about 2 days.
Cinnabar sells
>a kit for
>$350, which eliminates the leakdown due in part to the
aging of
>the system.
>The kit includes a high pressure limit of 120 pounds (there
is no
>high limit
>in the Electrolevel II system; a malfunction in a component
could
>allow the
>pump to raise the pressure to the point that the bag
explodes) and gauges,
>etc. Cinnabar also sells upgrade kits for the Power Level
and Electro I
>systems. Not cheap, but I want the system to operate the
way it
>was designed
>before I put the coach on the market.
>
>J R Wheeler central NC (glad not to be in Eastern NC).
>

 

[richard guthart]

Scott,

Are you sure the arrow should point toward the compressor?

I ask because this seems counter-intuitive and the opposite of other valves
which (I thought) mark the arrow to point in the direction of intended flow.
This includes the check valve in the Cinnabar upgrade kit.

Please don't get me wrong; I am not challenging your statement; I sure am no
expert. But sure would like confirmation of this before we start to tear apart
the solenoid valves and reverse them.

Richard

> Incidentally, as far as I know, all of the hold solenoids
> are installed backwards from the factory. Even the manual
> is incorrect about their installation. (At least they were
> consistent.) The solenoid valve has an arrow on the side of
> the body, which should point in the direction that you want
> the solenoid to "hold". In our application, we want to
> "hold" air in the bag. Therefore, the arrow should point
> away from the bag and toward the compressor.......

 

[bartz paul]

Scott:

Any reason you didn't replace the hold solenoids vs. the rebuilding? I
priced some 12 v Humphrey Products solenoids. They are available in either
normally open or normally closed. P/N 310-2-12 runs $22.45 + tax here.
What did you get that was so expensive??
If you have a drawing available for the Electro Level II system, that shows
the whole system, please e-mail a copy.

Paul Bartz

From: Scott Shean [mailto:shean]
Sent: Wednesday, September 22, 1999 2:08 PM

J R, I recently replaced the exhaust solenoids and rebuilt the "hold"
solenoids on my EL II system. The cost was about $160 for parts. The
system now holds air for weeks. BTW, the manual states that the exhaust
solenoid will limit air pressure to 150-180 psi.
Incidentally, as far as I know, all of the hold solenoids are installed
backwards from the factory. Even the manual is incorrect about their
installation. (At least they were consistent.) The solenoid valve has an
arrow on the side of the body, which should point in the direction that you
want the solenoid to "hold". In our application, we want to "hold" air in
the bag. Therefore, the arrow should point away from the bag and toward the
compressor. If yours are still in the original configuration, the arrow
will be pointing toward the bag, and you can get a nice improvement in
leak-down by reversing their direction.
From: owner-gmcmotorhome
On Behalf Of
Jrwheeler7
Sent: Wednesday, September 22, 1999 9:17 AM
Scott,
I failed to mention it in my post, but the upgrade is for the Electro Level
II for my coach. I have leakdown in about 2 days.
Cinnabar sells a kit for $350, which eliminates the leakdown due in part to
the aging of the system. The kit includes a high pressure limit of 120
pounds (there is no high limit in the Electrolevel II system; a malfunction
in a component could allow the pump to raise the pressure to the point that
the bag explodes) and gauges, etc. Cinnabar also sells upgrade kits for the
Power Level and Electro I systems. Not cheap, but I want the system to
operate the way it was designed before I put the coach on the market.

 

[scott shean]

Paul, as an owner of a 1978 GMC, you have either an EL I or EL II
system. My comments only apply to the EL II, however, I think
both systems have the same "hold" solenoid.

In answer to your question about new parts, my inclination was to
first try to repair the valves that I had. The cost of a rebuild
kit for both, was $41.00. Had it been outrageous, I probably
would have looked for new replacements. You might have saved
some money and upgraded to newer materials by replacing yours. I
took the easy way out by salvaging my existing pieces.

The other cost was the replacement of the two exhaust solenoid
valves that are internal to the compressor head. This was at a
cost of $123 for both. I don't know if there was a reasonable
alternative in this case, because they mount inside of the
compressor. For me it was irrelevant, as I was about to leave on
a trip, and the repair was not planned.

As for the diagram of the ElectroLevel II system, I can make you
a drawing, but the EL II system is very simple. and it is quite
easy to explain it in words. The EL II system has a compressor
(with a built-in exhaust valve), a height sensor, and a "hold"
solenoid for each bag. The "hold" solenoid opens and closes with
the ignition key. Once the ignition is on, the compressor and
exhaust solenoid are controlled by the height sensor when the
system is set to "AUTO." When the system is set to "HOLD", the
compressor and exhaust valve are controlled by the dash switches.
If you still need a drawing, let me know, and one will be on it's
way.

As simple as it seems, it's not without problems. After 20+
years, the pieces don't operate as they were designed. I have
had all of the components apart, and replaced/repaired each of
them. Having done so, I am confident that the system is well
designed, and needs nothing more than good maintenance.

Scott Shean
Baton Rouge, LA
78 Royale

>-----Original Message-----
>From: owner-gmcmotorhome
>[mailtowner-gmcmotorhome]On Behalf
>Of Bartz, Paul
>Sent: Thursday, September 23, 1999 2:58 PM
>To: 'gmcmotorhome'
>Subject: RE: GMC: Air suspension upgrades
>
>
>Scott:
>
>Any reason you didn't replace the hold solenoids vs.
>the rebuilding? I
>priced some 12 v Humphrey Products solenoids. They are
>available in either
>normally open or normally closed. P/N 310-2-12 runs
>$22.45 + tax here.
>What did you get that was so expensive??
>If you have a drawing available for the Electro Level
>II system, that shows
>the whole system, please e-mail a copy.
>
> Paul Bartz
>