Rear Air Ride Random Drops / Air Blending Door

[myrddin]

Hey guys, I have some questions... my H2 is a 2003 with the air ride in the rear. I have seen the rear drop down over night twice and am confused. I went out over this past weekend and aired up the bags full in the off road mode... I then got under with a soapy spray bottle and started to spray the bags down I spent like 30 min per side and even used my hand to soap it up and did not find any bubbles. I then (the best I could) started to spray the hose from each bag back to the compressor... No bubbles. I also sprayed the compressor where the hose connects on each side, and I didn't see anything... I checked the air stem inside where you can air up things and it was not leaking... I tried to follow the hose to the compressor and check it there and best I could tell it was also fine. The sensors look OK best I know... I think one was replaced right before I got it. But my thoughts are if it were one back sensors it would go down crooked? It does not do it all the time only twice that i noticed so far... no service air suspension on dash, and after I looked it over I left it up in off road mode all night and checked it with a tape... and it did not move a mm... I don't get it... thoughts?

Air blend door... this morning I noticed that i had cold air on one side, and hot on the other... I switched from dash to floor and to defrost and so on a few times and it seamed to even out. I can change from 60 - 90 left and right now but it may be a tad slow (hard to say I could be paranoid)... But I wonder if this was just cause it has been on cold so long and I just thought to try heat... or if this is an early sign of blend door failure.

any help would be great... I like my air ride suspension, and i know its problematic... but I want to keep it all in tact.

thanks in advance

[Easy Ed]

Back in 2006 HUMTECH made a post here http://www.elcovaforums.com/forums/showthread.php?t=20388&highlight=air+suspension about "If this is an early model H-2 with A single stage compressor there is a programming update to address your concern, talk to your dealer tech and he should know about it. Likely the service consultant or service manager will not have the info."

Maybe yours hasn't had the update ?

Good luck, Ed

[myrddin]

I wonder how I would know if it was a single stage compressor, or how would I know if it had the programming?

I just came in from being under the truck for an hour; I left it at drive height and got a flash light... For the first half hour I left the truck running, I never seen it drop nor did the compressor come on... the rest of the time I had it shut down and I sprayed everything heavy... no bubbles at all that I was able to find. I took a measurement at the end and I will compare that to what the numbers are in the morning...

I don?t get it... if there is a hole it should leak all the time... not when it wants... and my thoughts are when you air it all the way up it should be more noticeable that nay due to the pressure.

Crazy...

Thoughts?

and thanks for taking the time he help a guy out...

[Easy Ed]

Here is what a dual stage looks like. http://www.amazon.com/HUMMER-COMPLETE-AIR-SUSPENSION-COMPRESSOR/dp/B003P5BP9W/ref=sr_1_1?ie=UTF8&s=automotive&qid=1276051210&sr=8-1 As for the programming, if you can still find a HUMMER dealer (???) they should be able to run the VIN and tell what has been done to the truck, I'd think ?

Ed

P.S. I am one who elected to convert mine to coils so not to have problems with the system that kept cropping up on me.

[myrddin]

Hmmm... at a glance I do not think mine looks like that... but I will check agn tomorrow...

[Easy Ed]

The 2003 only got the dual stage if the original was replaced for a problem under warranty or for that matter even after the warranty and the owner paid for it. Also, I think it was a year or two before they came out with the dual stage.

Ed

P.S. Re-read the link and it was 2005 when they came out with it.

[myrddin]

IC... so it could be that it needs the reprogram? I will call tomorrow and ask my local Hummer dealer... I know someone over there that might help.

I am pretty sure this is my compressor:

[Easy Ed]

Yup, I bet you are correct that it is what's in your truck.

Ed

[myrddin]

Any idea what all the reprogram does? Like is it a flash for other things as well or just specific to the compressor. My blend door was acting odd today as well, but after I messed with it a bit it started to work better... could have just been one of those days...

woke up and the back end was down, and then I for whatever reason tried the heat, and it was cold at 90 on driver side and hot on pass side... I switched it up and down and moved the heat to cold and back a few times and it seems OK I think for now... I will try it agn in the morning.

[myrddin]

Well my measurement shows it dropped almost 4 inches this morning... I don?t get it... The bags do show some cracking but no bubbles at all when I spray... I guess I am not sure what to do. I am going to take a measurement when I get to work... Ind another when I am done to see if I notice anything.

[myrddin]

When I got to work and parked it I measured about 40 1/4 on the driver side and about 40 3/4 on the passenger side... I will chk agn about 5:00 today when I am headed home. I just called the Hummer dealer and had him check the vin (he asked for last 8 digits) and he said it had no due recalls but would need to hook it up to the GM scan tool to see if it was at the latest revision of the software (he says that is all software on the truck). It will cost 97.00 for them to do that and that is even if it does have the latest code... so I will have to pay no matter what. That is almost one airbag... I wish I had a way to tell exactly what was the problem... I do not want to throw money out the window unless its for what needs to be replaced.

any ideas, is there something that will help me indicate what software is on the truck (like how the compressor acts or what something else does)... And is there anything else I can do to test the bags ot lines or compressor?

I would like some reassurance is all... I do not think its smart to just toss money at it till it is fixed.

[Scarsman]

I am not familiar with the air system, but if it adjusts itself automatically then ther must be a valve somewhere for letting air out. Could there be some dirt or something in the system causing the valve to nt quite seal every time, slowly letting air out? This could explain why it does not do it every time. If the lines and bags are not leaking, then that is all I can think of.

Just throwing out ideas.

[HUMTECH]

Here are the symtoms fo the recalibration issue.
Some customers may comment on a Service Air Suspension message and/or a clicking noise from the rear of the vehicle when the vehicle is shut off and the key is removed from the ignition and/or the ECAS compressor cycles too frequently while the vehicle is running. Also could be opening and closing the exhaust valve letting air out of the system.

[myrddin]

thnx HUMTECH... I will start to pay attention... I do know that it will level its self out when I stop and go, or if I get out with it running... and it will go threw and raise and then it will lower until its where it wants to be... but I do not think it runs at all when you turn the key off... or at least not that i have ever seen?


I will tell you this (for the record so far)
at 2:36 today I measured Pass - 40 3/4 and the driver was 41 3/4

I will measure it agn before I drive home.

[myrddin]

Checked when I got out of work was the same as 2:30 ( Pass - 40 3/4 and the driver was 41 3/4)

Checked after my drive home:
Driver - 41 1/2
Passenger - 41

I guess I will chk it later tonight. I dont know what to do at this point.

[Easy Ed]

Hate to say it but ya just got to let them run the scan tool on it, check for any codes and check the software for any updates. They may even be able to tell you what is wrong with the heater/ac problem also while doing the scan. It is a painfull thing to pay for but no a days it is the only way to keep from throwing money at it hoping to find the problem. I have a power programmer that will also read the codes and clear them and point me in the correct direction to fix most things, it helped me when the memory module went bad in the drivers seat.

HUMTECH is a great person that takes the time to help us out here but I think he will agree that checking for codes and the software version is a good thing at this point to help resolve your problems.

Agreed HUMTECH ??

Ed

[HUMTECH]

Absolutley i agree. Software problems can be impossible to diagnose you just kinda have to put faith in the writers. I fix probably 2 to 4 problems a week on average with software updates. Sometimes just reloading the current software can fix an issue just like restarting a pc or reinstalling software on a pc to correct for some glitches. Thanks for the kudos Ed...

[HUMTECH]

Also if there was a level sensor replaced the ride height calibration needed to be done, if not that will cause issues as well. The dealer can check in the data list if it is learned or not. another thing to check to get your moneys worth

[Easy Ed]

You are welcome. Just giving credit where credit is due :beerchug:

Thanks for the kudos Ed...

[myrddin]

I understand... I just don’t get how the software can let the rear drop over time like that... Seems like I could hear it or something...

Currently at: This is as of 8:25pm...
Passenger 40 3/4 best I can tell
Driver 41 1/2 (-2 mm)


So let’s look at it like this, its dropping, so air is coming out of something... Is there an exhaust valve that has a vent for the air? Would it be dumb to try to put a balloon over it to see it shows signs or air escaping?

What if it’s a leak somewhere I can’t see to spray?

Man, it’s bad enough when you need to work on something but usually you know what it is.


The air is currently working, it was just the one time... but like you stated... could be sign of what is to come.

If you guys say its worth my time then I will do it... I just wish I had more signs to point my finger at is all.

I did find this and I am not real sure what it means (like what had to be fixed) but:
Suspension & Steering: SUSPENSION:REAR
Service Bulletin Number: 3472
NHTSA Number: 10014856
Model Years Affected: 2003, 2004, 2005
Date of Bulletin: 05/2005
Bulletin Summary: REAR END OF THE VEHICLE APPEARS TO SAG AFTER THE VEHICLE SITS OVERNIGHT OR LONGER.

located: http://repairpal.com/hummer-h2-2003/recalls_and_tsbs

[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)

http://gsi.xw.gm.com/image_en_us/gif/000/999/999/999999995.gif 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.
<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).
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)

http://gsi.xw.gm.com/image_en_us/gif/000/999/999/999999995.gif 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&ssPageName=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:
http://www.elcovaforums.com/forums/attachment.php?attachmentid=52844&d=1281148322

After:
http://www.elcovaforums.com/forums/attachment.php?attachmentid=52845&d=1281148388

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.

[Hummerguy32]

Just Today went to the hummer dealer and had them reprogram the code from humtech requested it cost me 105.00 They said it took some time for the computer to accept the new code...whatever that means?? And then they charged me 63.00 additional dollars to adjust carring heights on the airbags... What a joke. Is this even reality or is it something they just made up?? Thanx Humtech.