Hello,
I'm having issues on resolving the leak of the air suspension, Hummer is from Connecticut since new. 68000 miles
It started to sit low once in blue every month. now it's about every night. I replaced the bags, I checked the leveling sensors by pushing it down which will lower your car and I pushed it up which will raise the car. That works. I looked at all the lines seems ok. I'm thinking to take off the compressor assembly down to inspect. Does anyone have any advise on what can be wrong?
Please advise

 

You could try mixing up some soap and water in a spray bottle and soak all your connections, lines etc and get someone to raise and lower it from the cab. Watch for air bubbles.

 

That would be my suggestion as well. Some soapy water in a spray bottle should find that. If it leaks down that fast you will probably even be able to hear it if you have a very quiet place to listen.

 

Your AS unit is most probably a dual compressor system as on the 2005.

As it happens I've done a strip-down of most of the unit and so have quite a bit of info on it, so to start you-off see attached JPG and PDF

You can try the soapy water on the pipes etc however access is pretty limited but you may be able to un-bolt the unit and lower it down a little. Hopefully you will get lucky and find a simple leak.

I'm assuming that both sides are dropping equally, if true it seems a little odd considering there are individual Right, Left and Exhaust valves to control inflation and deflation of each air-bag individually.

So I believe the unit operates is as follows:-

1. For Inflation both Compressors are turned ON, the Exhaust Valve is OFF and the Inlet Valve operated for the side that needs raising ( it could be both)
2. For Deflation both Compressors are switched OFF and the Inlet Valve operated for the side that needs lowering ( it could be both) and the Exhaust Valve turned ON

Note: The compressors are twinned together, not one for each side as you may think.

Some systems have a tyre inflator which connects directly to the output of the compressors.

As far as I can tell (and I have my old AS Unit in front of me) for both sides to deflate it would require both Left & Right inlet valves to leak, or possibly just the Exhaust Valve (but I can't see how as with the ignition off this would mean the bags would be connected together with both valves open)

Anyway I have actually stripped-down the inlet valves completely, thats all the little O-Rings, plungers, clips etc and I have to say considering their condition I'm amazed my AS unit operated at all (mine had a faulty ECU which I also repaired)

So in short I'd guess its the Inlet Valve Assembly leaking, in the past I looked for replacements but could not find any, that's not to say there arn't any.

It was my plan to make a YouTube video on this topic but just haven't had time yet.

Good luck with the repairs and please post what you find, hope the data helps.

 

So more information

 

Wow, thats some good info. Could be a "sticky". I made sure i bought one without the air suspension. But should be valuable info for many.

 

Just for you see video

 

I really appreciate your response and knowledge which makes me want to take down the compressor assembly and clean it up , make it look new again. I did look down at the lines and bags again and noticed something weird at the fitting on top of the bag where the air tube goes, its leaking from there it also increases when I press down on the fitting or bend the tube around. Drivers side left side. This tells me two things, either the gm factory sent me a defective air bag or when I had the bag replaced about 3-4 years ago at the shop they broke the end on the tube and just made a clean cut because I noticed it did not have a little ring look a like on the end tube like the passenger side did.
Any opinions on this? Has anyone came across a defective fitting on the air bag?

I will order a new tube since it's only 10$ but what worries me if it's a defective air bag.

Plus what I also noticed, just a tip. I did not have to cut the bags to to deflate it is what I did because I followed instructions from net. Just raise the body take the wheel wells off and pop the lines out. Simple as that, alot easier than going from under heath.

 

The ring look a like on the end of the tube is about a 1/2 an inch from the actual end of the tube.

 

Re the wheel wells, great tip and makes a lot of sense, it means you keep the bags intact just in case it was something else or if you have problems with the replacements!

Sounds like you've found your leak, or one of them at least.

The little "ring" indent looks like its caused by the air-bag fitting itself, I have a brand new one here and I can clearly see the "gripping" retainer inside, but can't be 100% positive.

If the shop cut your tube a bit short it might not be fitting deeply enough or it could be under strain, I think your 10$ could be a wise investment, but hopefully its not the bag itself.

The the new bags I have here look very cheap , I bought them "just in case" and never used them, so the air-fittings I will definitely check before I install them.

Keep us posted!