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Discussion Starter · #1 ·
About 6 months ago my Envoy started dropping in the back, However it was not constant, It would drop in 2 min or 2 days and anything in between. However as of late is has got to the point it will drop while driving down the road! This does pose a problem as I guess you could imagin. Also it seems that the bags will deflate A LOT faster after it hits a certain point.

I know you guys have seen this a 1000x before. Let me give you a run down on everything that I have done so far. By reading these forums and a few others they all stated my problem could be caused by a bad compressor. So I bought a new compressor. The problem still exists!

But I finaly got some help when working on my Envoy and I was able to spray soap on the air shocks when someone sat on the back. I was able to see LOTS and I mean LOTS of little air bubbles forming from all around the Air Shock. So I am guessing that this is my problem and I plan on changing them out with some I got at a salvage yard.

My question to you guys is!

Is this normal for the bags to leak air? Or do I have bad bags?

The reason I ask this is I know the system is suppose to raise and lower the back depending on the weight. Does the pump allow the air to come back out? Or does it leak through the bag?

Thanks for your advice!
 

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2004 gmc
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The compressor assembly has both inflation and deflation valves. The bags themselves should be sealed perfectly.

Wish you had posted instead of just lurking all this time. Could have saved you a couple of bucks by advising to do the soap spray first.

You could also swap the bags out for coil springs from the normal vehicles, if you don't need load-adjustability. Cheaper long-term maintenance.
 

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2003 chevy trailblazer_lt
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I'm not familiar with the air ride on the TV, but I have owned a truck with air suspension. I could be way off, but are there check valves on this set up? If so, maybe the check valve is bad and needs to be replaced. But like I said, I'm not familair with these... it's just a thought... :confused:

Edit: sorry about that, I read the post, then went to get my son something to drink and came back and replied. Then I remembered you already found the problem.... I fail.
 

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Discussion Starter · #6 · (Edited)
I actualy sprayed them before I forked out the money for a new pump, but I couldnt see anything bubbles at that time.

I have a 2004 Envoy with 120k miles.

All the bubbles I had seen was around were the fold would be, and they seem to get worse as the Envoy went down. Too me they looked like Age cracks (IE Dryrot) but I didnt know if the cracks was just how the bags keep the air in check.

BTW they are small small leaks but like one every 1/4 inch or less.

Today I am going to change out the bags with some that I got when I got the used pump at a salvage yard. I hope these are in better conditon.
 

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2004 gmc
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yes I believe there are check valves on the bags themselves..
I don't see mention of them in the shop manual. The exhaust valves are discussed as being part of the compressor assy. If the bags had valves, there would have to be control wiring to them, and the schematic doesn't have anything. Do you have a reference for valves being on the bags?
 

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I don't see mention of them in the shop manual. The exhaust valves are discussed as being part of the compressor assy. If the bags had valves, there would have to be control wiring to them, and the schematic doesn't have anything. Do you have a reference for valves being on the bags?

I could have sworn someone said there were check valves on the bags.. maybe im wrong :x
 

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Discussion Starter · #9 ·
Yea I read about the check valve as well. However from what I can tell there is NO check valve of any type on the bags.

The good news is that I did change out the bags today and I have to say 100% better. The old bags were dry rotted with cracks BAD one was even 1 inch long and you could see the webbing inside the rubber.

I dont know how long the used ones will last, but I did find a website were you could get new bags for 125 a bag. Anyone know any cheaper place I would be glad to hear it.
 

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I could have sworn someone said there were check valves on the bags.. maybe im wrong :x
I used to spout misinformation all the time as I was learning about the systems. Now I'm a mod, I went back and cleaned up and fixed all those old posts so it looks like I was a perfect, 100% troubleshooter of the root cause of all problems ever posted on trailvoy.

Like going back in time should allow you to get rich in the stock market (assuming you have a good memory).

Just kidding, of course, but if it makes you feel better about your memory, you can latch onto that explanation. :D
 

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2002 gmc envoy_slt
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Was it hard to change the bags?

My 2002 Envoy has 115,000 miles and I have a new set of air springs I bought on ebay a year or so ago.. I know mine are dry rot as last time I replaced the compressor I could see they were nearing the end of their service life.

Can you give a little insight for me on replacing the bags? :thx
 

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2003 olds bravada
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I dont know how long the used ones will last, but I did find a website were you could get new bags for 125 a bag. Anyone know any cheaper place I would be glad to hear it.
Care to share where you found them? The Bravada is starting to do this. It was happening every few weeks but now it's happened in just a couple days. I'm afraid I'll be needing to replace these soon. I like the system and would like to keep it working right. Thanks!
 
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