Rear Air Ride Random Drops / Air Blending Door

[myrddin]

OK, I just got off the phone with a Hummer tech; he knew quite a bit and had some good info to offer. He says if i have the code 711 it could be that I need the update and it might be ok... However he said the 2003 suffers from having a bad system... he says the new dual compressor fixed all the problems... He says that the single failed in many ways but the most common was corrosion build up or debris that causes the exhaust valve to hang and leak air... he stated that sometimes it could not hang because the decree would move but then it might end back where it hangs up the valve... but he said if I want to test it I can remove the gas cap, and then remove the filler neck surround ( 3 screws and turn counter clockwise) and move the filler neck to the side I will see the filter and exhaust line... he says easiest thing to do is place a condom over the filter for the exhaust hose and let it sit and if I see air fill it up overnight I will know that it how the air is escaping.

So now I have another thing to test...

He did say the code read would be 50/50 but the fix now or later will be the upgraded compressor... like 2500.00 worth of parts.... that I do not have at the moment.

what do you guys think?

[HUMTECH]

#PIT3509: 2003-2005 Hummer H2 Vehicle Sits Low or the Suspension Sags Overnight - keywords AIR control DTC ECAS ELC electronic height inoperative leak MIL module rear spring trim - (Mar 23, 2005)

Subject:2003-2005 H2 Hummer Vehicle Sits Low or the Suspension Sags Overnight

Models:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss1-1634083">Condition/Concern:

Some customers may comment that the rear of the vehicle sits low and/or the suspension sags overnight.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss2-1634083">Recommendation/Instructions:

Check the following locations for a leak using a soap and water solution in a spray bottle.

1. <LI type=1>Left and Right Inlet Valves. <LI type=1>Exhaust Valve. <LI type=1>Suspension Air Supply Lines that run from the Inlet Valves to the Right and Left Air Springs (Airbags).
2. Air Spring fittings and the Air Spring itself.

Leakage can produce big bubbles or just some beer like foam appearance. If the leak is isolated to the valve block assembly, do not replace the entire compressor assembly. The valve block can be obtained separately by ordering part number 88982408 for the single stage compressor or part number 89060584 for the dual stage compressor.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1634083&from=sm#ss3-1634083">Models:

(2003-2005 Hummer H2)

[HUMTECH]

#PIT3472: 2003-2005 H2 Hummer Rear Suspension Sags/Leak Down Specification - keywords AIR DTC ECAS ELC electronic height inoperative MIL Module trim - (Mar 4, 2005)

Subject:2003-2005 H2 Hummer Rear Suspension Sags/Leak Down Specification

Models:

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss1-1618502">Condition/Concern:

Some customers may comment that the rear end of the vehicle appears to sag after the vehicle sits overnight or longer. After the vehicle is started, the rear of the vehicle rises to normal operating level.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss2-1618502">Recommendation/Instructions:

To correctly measure for a concern, use the rear suspension "D" height measurement. The D height is obtained by measuring the distance between the edge of the jounce cup along the jounce bumper center line and the jounce pad on the rear axle (See SI Document ID # 796914).
A 1.0 mm (0.040 in) leak down drop of the rear end over a 24 hour period is considered normal.
Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
<A href="http://gsi.xw.gm.com/si/showDoc.do?docSyskey=1618502&from=sm#ss3-1618502">Models:

(2003 - 2005 H2 Hummer)

[myrddin]

Wow... good info... Should I be measuring the bumpstop travel instead of the ground to fender?

I was not able to see any bubbles, but to be honest I had a hard time getting to the top of the compressor... He (the tech I talked to) said I would never find that valve, I guess it’s not made any more? But let me ask you this... if I do what he said and the condom (or whatever balloon I can find to fit) fills with air... should I replace the valve if I can get it to still reprogram first.

For the heck of it I am going to soap it all down agn tomorrow after work I will do a better job at trying to soap up the fittings on the compressor.... If I see no bubbles I will put the balloon on the exhaust line at the filler neck and see if it airs up... if it does I need to figure out what to do...

1. Replace the compressor valve
2. Have dealer reprogram
3. Replace the single compressor with dual (I don’t have the money but I can start to save up or find one used)

You guys are real cool for lending a hand...

I value your opinion please help me get my mind straight and I will try to get it right.


do you think my steps sound right?

[HUMTECH]

I would try the program. The valve is not a service part but part of the complete assembly. So if the 100 dollar program works, great. If not your gonna have to replace the compressor at a huge cost. In my opinion a good 100 bucks to spend on diagnosis before the 2500 dollar plus repair.

[HUMTECH]

But like the tech you were talking too it may be a good idea to start thinking about the upgrade for sure.

[myrddin]

Thursday Morning:7:25am
-driver 41 1/4 (minus 1 mm)
-Pass 40 1/2

Parked at work 8:15am
-driver 41 3/4 (minus 1 mm)
-Pass 40 3/4 (minus 1 mm)

So its my guess that from your posting that this is normal (no real drop over the past 24 hours)...

Thinking back I am wondering if I only notice the big drop after I put it into off road mode and then back to normal... if I have not seen a drop by end of day I will test that tonight. If that is the case programming would start to add up for me... But I do not think that is it.

HUMTECH you are real cool to take the time to lend us clueless guys a hand... Let me ask... other than testing out my theory above on the off-road mode triggering the rear drop... Do you still think I should just take it over for a scan? or should I test the exhaust valve for failure first... and I found 2 guys that have the dual stage compressor (one with hoses and bags) that I can get "Used" for under 400.00... should I skip the scan and just do that? I mean I would hate to pay 400 or so when I may get away with 100.00. But also I would hate to spend 100 on something that will not help when i can add that to the total for the parts I need... those compressors will not last long at that price I wouldn't think...

thanks

[HUMTECH]

If you can get a working dual stage setup that cheap i would grab it. Once installed it will have to go to the dealer though to have the trim height learned

[myrddin]

OK... let me recap once more before I decide what to do...

over the mast month I have seen my truck about 4 inches lower than normal when I came out to go to work.... other than that it seems normal (from what I know) it may drop 41 1/4 to 41 or might settle in a 1/2 inch... But it does not happen every night only 3 times this month (so far)... Now it seems like those 3 days I was fooling with the plus 2 inch button (I call it off road mode) and then the next day is when I noticed the drop... I could be all wet on that idea so I will test it in the morning.

So I have soaped it down twice (and I know it can be hard to find the leak) I was told not to fully inflate cause it may seal a bag leak it there is one so I also tested it with it at stock... both times I could not see anything obvious so not sure. However if when it does drop it comes out of the exhaust line then I may only see it with the condom trick at the top (like the other tech said)... then I guess it could be the exhaust valve failing...

so long story short, I don?t get why its random in my book if its broke its broke, I guess it could be the start of valve failure and that would make sense...

so with all that said... I still have not seen it drop agn

4:25
When I pulled in the driveway and left it
Pass - 41 1/4
Drive - 41 3/4

7:15
Walked out to chk
Pass - 41
Driver 41 1/2

I will chk it before bed time and post back... if it?s not dropping than the no reason to chk the exhaust...

What should I do?
400.00 may get me the pumps (used) but I may not get the lines... I would have no money after that to run to the dealer for trim... it would need to sit till I had more cash to do it... I would like to put this behind me... hell it may never drop agn... I dont know.

[HUMTECH]

Heres my 2 cents. Intermittant problems are gonna be wiring, module or software issues. Hard parts fail and continue to do so. It may be fine for now, but like i said that is cheap for the dual stage. Buy it now while yours is still working, save a few more dollars and buy the rest of the parts. Save a few more and install it and get the setup done. Only thing i would wonder about is why the seller is giving up the dual stage so cheap. Buyer beware. Or just convert to coils.

[EuroHummer]

i gave up on mine and ordered 6" lift coils from Fabtech. I replaced two airbags, and then had more leaks, etc. just like you.

[myrddin]

the dual compressors are local craigslist guys... one is off a 2007 and is real clean but no lines... the other is also off an 07 but is rusty however comes with bags (no lines).

what do you think? It did not show any drop this morning so I aired it up then let it down... i will chk it when I get back.

8:00am
pass - 40 3/4
drive 41 1/2

for the test
aired it up and down
pass - 40 3/4
drive 41 1/4

I will report back after work...

[myrddin]

just found out when the guy replaced the driver side level sensor that he did not have it recalibrated... says he just swapped it out... wondering if that would cause it to drop a few times like I have seen? Over 30 days I have seen it lower than normal 3 times... all other times it?s been pretty close to what I would expect...

[myrddin]

Well I am not sure if the fact that when the guy replaced the sensor on the driver?s side may have added to this... suspect not or it wouldn?t work at all... But with me only seeing it drop 3 times in over 30 days now I am going to hold on replacing... but in the same time work on getting the upgraded compressors for future use. I just can?t see guessing at what to replace... for all I know HUMTECH is right and the programming needs to happen... he is the expert not me... So I may replace the bags myself since they do show signs or dry rot and I will take to the Hummer dealer to have them reprogram the truck and chk the level and trim... If they find codes I will make note and work it from that direction... thoughts are that at least it will limit the guess work... and if they say I just need to replace the compressor... then I know my direction for sure.

I found this on eBay and I was wondering if the bags were worth the money, or should I only replace with the firestone brand:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=330453332305&ssPageNam e=STRK:MEWAX:IT



I just let a used 2007 dual stage compressor go... I hope I made the right choice

[myrddin]

Part One of Bag Replace...

OK, So I got the bags today, and they are in fact the same ones on it "Factory"... I jacked up the tuck from the rear end as high as my 3 ton would go (not as high as I would have liked). Then I put jack stands under each side of the frame for support and chock/blocks in front of each tire. I then let the jack down all the way (well till the tires were back on the ground)... then I took my knife to the bags... note the passenger had little air in it (or at least compared to the other it had way less pressure). After which to give me more room I cut the bags in half to give me more access... Now the hard part is really (or at least so far) getting the lines off... Only way I could do this was to push the retaining clip in and turn counter clockwise to take the top of the bag out of the frame... then I used both of my index fingers to hold down the metal ring on the bag where the hose connects to it and it tried to hold the line as well and pull, at one point I could not hold the line and gave a tug anyway and it popped out... If you had a buddy here to hold the line as you pulled the bag it would make short work of this. Once I got them both out I said to myself it?s a great time to clean the frame up and use my Eastwood frame restore kit I had sitting on a shelf So I will continue on tomorrow with shots of the frame clean up... I hope this will benefit someone in the future... But just know it is an easy job over all (So Far).

Pics:

[myrddin]

Just wanted to post an update to this thread:

I replaced the air bags and it seems to be fixed, after seeing the bubbles from the last test I felt pretty good about replacing them... While I was at it i also painted the frame and rear axle... looks better than new and no more sag.

Before:


After:


Thank you all for your help... I hope something in this post helps another Hummer buddy... I also hope I can return the favor sometime.

Humtech and Ed... you guys are too cool... Thanks.

[Hellz]

picys no worky

[myrddin]

Odd... I re-saved them... if that doesnt work I will try something else... I may post more tomorrow...

[myrddin]

Humtech, you post say?s that a loss of 1 mm overnight is the max acceptable drop... Is that realistic? I am wondering what I should expect, I parked my Hummer and plan on measuring the why you post says to measure... I am going to let it sit for an hour, then go out to get the measurement from the bump stop cup to the pad on the axle and then check it agn in the morning...

To be honest, I think it will settle in more than 1 mm.

Hope you have time to read this?
Thanks


Anyone else that has checked can you chime in as well?

[MJB_Hummer]

Do you live somewhere where it gets cool or cold at night?

I had the same exact symptoms and also could not locate a leak with the soapy water. The problem is that when the bags are at normal ride height they fold over on themselves and when it is warm out, say 50 to 60+ degrees out they will not leak because the rubber is soft. But when it gets colder out the rubber is stiff and it will leak from the crease, I replaced the bags and problem solved. Everyone says to go to springs, but I like the air ride and the bags are cheap and very easy to replace. Did it in just over an hour.