Front air bags deflating

[jdlashua]

My front air bags deflate about 5 minutes after I secure the engine.
The pressure gauges for F/R air tanks remain good. The low pressure
warning light doesn't come on. I've dumped and refilled several times,
but still does the same thing when I shut down. Is there a check value
in the height adjuster or somewhere else that may be giving way or am I
looking for a slow leak in one of the lines. Anyone have any advise how
I troubleshoot this?

James Lashua
84PT40

[Curt Sprenger]

I have the same problem but the time is an hour plus. Will be interested
in the replies.

Curt Sprenger ‘87PT38, Anaheim, Calif.


jdlashua wrote:

> My front air bags deflate about 5 minutes after I secure the engine.
> The pressure gauges for F/R air tanks remain good. The low pressure
> warning light doesn't come on. I've dumped and refilled several times,
> but still does the same thing when I shut down. Is there a check value
> in the height adjuster or somewhere else that may be giving way or am I
> looking for a slow leak in one of the lines. Anyone have any advise how
> I troubleshoot this?
>
> James Lashua
> 84PT40
>

[Jeff Miller]

The front and rear air gauges are for the front and rear brake
systems, will not drop below 75psi unless the brake system has a leak
(well, will eventually but usually not for days).

The accessory system is shared by the air step, air suspension, seat
slides, vents, horns, etc., and will often lose air fairly quickly
due to a leak in any of these system.

A common culprit is the air step, if you hear it leaking it will
drain the system and eventually the airbags. Another common cause in
the pre-'84 is the vacuum generator / aspirator for the cruise
control. Any leak will eventually drain the airbags.

Why the front often drops and not the rear I haven't looked into,
I've seen it on several coaches, possibly the front leveling valve is
using more air to keep the front up.

- Jeff Miller
http://www.wanderlodge.net
http://www.millercoachworks.com


--- In WanderlodgeForum@yahoogroups.com, Curt Sprenger
wrote:
> I have the same problem but the time is an hour plus. Will be
interested
> in the replies.
>
> Curt Sprenger `87PT38, Anaheim, Calif.
>
>
> jdlashua wrote:
>
> > My front air bags deflate about 5 minutes after I secure the
engine.
> > The pressure gauges for F/R air tanks remain good. The low
pressure
> > warning light doesn't come on. I've dumped and refilled several
times,
> > but still does the same thing when I shut down. Is there a check
value
> > in the height adjuster or somewhere else that may be giving way
or am I
> > looking for a slow leak in one of the lines. Anyone have any
advise how
> > I troubleshoot this?
> >
> > James Lashua
> > 84PT40
> >

[Scott]

James, in our 86FC I just found the culprit with similar situation to
yours.. in addition to the coach leaning to port..in my case it was the
front leveling valve leaking. You can remove the valve and leave
the "arm" if you will by disconnecting it and taking the air lines
loose. In my case the rubber seal/gasket was leaking behind the valve I
simply made a "new" rubber gasket and hooked it up and she stays up for
quite a while now. Ride height is a little high (21") but bags don't
look bad. So I figure I can use a little extra clearance!! I have some
other leaks to tend to but those are on the "list"..
Scott
86FC35 "RUBY"
Murrells Inlet SC (where all the harleys in the world are right now)
--- In WanderlodgeForum@yahoogroups.com, "jdlashua"
wrote:
> My front air bags deflate about 5 minutes after I secure the engine.
> The pressure gauges for F/R air tanks remain good. The low pressure
> warning light doesn't come on. I've dumped and refilled several
times,
> but still does the same thing when I shut down. Is there a check
value
> in the height adjuster or somewhere else that may be giving way or am
I
> looking for a slow leak in one of the lines. Anyone have any advise
how
> I troubleshoot this?
>
> James Lashua
> 84PT40

[George Lowry]

The system is quite common to all the coaches with air suspension.
You have a height control valve that adds or releases air as necessary
to keep the height above the axle the same depending upon atmospherics
and/or load variations. Normally this valve has a delay built in so
that gong over bumps does not trigger a change in air pressure.

The valve should be rebuildable. I would check to see if there is a
kit available. (I know they are for the GM coaches.) If not, then you
may have to change the height control valve. They usually run around
$50 and are easy to change. The lines from the height control valve
including connections, and the bags themselves, may be the cause of
the leaks. Sometimes it only takes a 1/4 turn on a fitting to stop a
leak. That is where the ultrasonic leak detector comes in handy to
determine just exactly where the leak is. Without it is trial and
error, or possibly using a soap spray.

Hope this helps,

George Lowry
'95 WBDA 4203 & GM 4106 (for sale)
Spearfish, SD



Curt Sprenger wrote:

> I have the same problem but the time is an hour plus. Will be interested
> in the replies.
>
> Curt Sprenger ‘87PT38, Anaheim, Calif.
>
>
> jdlashua wrote:
>
>
>>My front air bags deflate about 5 minutes after I secure the engine.
>>The pressure gauges for F/R air tanks remain good. The low pressure
>>warning light doesn't come on. I've dumped and refilled several times,
>>but still does the same thing when I shut down. Is there a check value
>>in the height adjuster or somewhere else that may be giving way or am I
>>looking for a slow leak in one of the lines. Anyone have any advise how
>>I troubleshoot this?
>>
>>James Lashua
>>84PT40
>>
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