Air Bag Suspension - Leak

[Fin4]

I have a 77 Airstream Argosy 28ft MH that just had the air bags replaced (Firestone air bags).

My problem is it takes 1 hour to fill the air bags up via the air ride factory compressor that came with the vehicle. This is with no one in the vehicle and not moving it an inch.

This has got to be wrong.
Q: How long should it take the compressor to fill the 2 rear air bags up once you put the key in the ignition.

Then after you turn the engine off and lett the vehicle sit, not moving it at all, the 2 back air bags deflate in 30 minutes. And the back of the vehicle is sagging near the ground. A loss of 4 - 6 inches from being near fully deflated.

This has got to be wrong as well.
Q: Should the air bags deflate in 30 minutes (sag near the ground) with no use at all, being nearly full and brand new?

Wouldn't the air bags stay near full inflation.

Q: About how long does it take (minutes, hours, days) for the back air bags to deflate and sag near the ground?

The prolonged time it takes to fill the air bags up is running my battery down to the point it has no juice to start.

I'm thinking there has to be a leak somewhere.
Q: Any suggestions on where the leak might be coming from? Could the air bags be installed wrong? I had it done at an mechanic's shop.

[Fin4]

Any experience, suggestions or advice would surely be appreciated.

[Smartstream]

Your air compressor is probably very tired. It should only take 1 to 3 minutes to inflate.

The bags will go down with time, some in hours or overnight, some hold for days or even weeks. The leveling valve and fittings are likely culprits. The bags are pretty tough if installed properly. The Airstream manual says it is normal to loose pressure if the RV is not used for a few days.

[Isuzusweet]

It most certainly sounds like you have a leak in the system; it could be the air compressor itself with the air leaking out of the head. Take some dish soap, mix with water and spray components (careful not to spray electrical wiring), compressor head, check valves, junctions, etc; bubbles are leaks. Make sure you check the air tank as well.

Cheers
Sidekick Tony

[Fin4]

Smart thank you! Would it matter if the air bags were actual Firestone air bags or if they were bags made by a remanufacturer?

[Fin4]

Isuzu thanks... As I look closer, it seems the air bags are not genuine Firestone. Not sure if that would play apart. It doesn't seem right that the brand new air bags would deflate so fast.

[Smartstream]

I wouldn't worry as much about the manufacture of the bags as much as the installation. Like Tony said spray everything with soapy water. The fittings on the top of the bags are particularly difficult to reach, start there with a mirror. Also check the exhaust port of the leveling valve.

[WayneG]

You probably have multiple problems. If you have a air storage tank of any size that can take a while to get up to pressure.
The compressor is probably a piston type and will not hold any pressure after it is off. There should be a check valve after the compressor. If the check valve leaks, that could be a reason for the early deflation.

If you do have a storage tank, check the drain valve for leaks along with the other plumbing.

[Fin4]

Really good advice thanks.... Could there be a moisture trap that needs replaced?

[cliffcharb]

I’m not familiar with the air system on the motor homes, but If the compressor is mechanically driven I would first look at a faulty governor as that cuts the pressure off and on. As far as leaking down it’s simply a leak somewhere.

[mayco]

You've got a leak somewhere. The soap test is the best way to find it. In addition to what others have said, there is a check valve inline from your compressor. These go bad and let air leak back through the compressor. So soap test around the compressor head also.

[Smartstream]

The check valve is a very important part of the system. It keeps compressed air in the tank by preventing it from bleeding back into the compressor. The leveling valve prevents compressed air in the bags from bleeding back into the tank.

Now if the bags bleed down the leveling valve opens allowing higher pressure air in the tank to refill the bags. If there is not a supply of higher pressure air in the tank, the bags will continue to bleed down. I can't say if there is a check valve function in the leveling valve. If not the bag air will flow to the tank, bleeding down even faster.

[davejay]

Hey,
Did your bags hold air before you got new bags?
There's a check valve on the compresser to let air out but not to bleed back through the compresser.
My guess is your compresser is running, and pumping, but your level valve or vales are bleeding off air almost as fast as the bags fill. Disconnect the arm on the level valve. It will go to the middle of its travel. The pump will fill the tank and bags. Load the bags up to where they look correct height wise. Turn off the engine. Now you'll have a full air tank and full bags. If you got a leak. They lol bleed off and you lol know it's in the lines or the bags or the compresser check valve. If they hold, and they should hold for weeks. My 325 is still holding air on my new bags from last fall.
Anyway, make sure the level valves are in the neutral position as in the lever is in a place to where no air is going through them . With the bags up, push up on the level lever, a couple of seconds will go by, and you'll hear air going into the bag.
You could have a bad level valve. Any truck shop will have them in stock. A big truck stop will also carry them. It's the same valve used on the bags for leveling the cab air bags. One line in, one line to the bag, and the exhaust port line.
Hope this helps. DJ