Allroad Air Suspension (or valve) problem

[MK13]

The issue I am having with my '02 Allroad that is a little weird. I did some searching but didn't really find my exact issue.

My problem started a few months ago, occasionally when I would park the car overnight my left rear bag would be deflated in the morning (usually about 8 hours) but not always. So I figured leaking bag ,no problem just confirm the leak and get a new set of rear bags. However I couldn't find a leak in the bag and that combined with it not leaking out all of the time led me to just let it go for a while.

Now, however I am getting complete deflation from the left rear and left front bags. It also happens much faster now (maybe 3-4 hours) however here is the interesting part. When I drive the car it almost always sags, however when my wife drives the car it almost never sags even after sitting for several days at a time.

So since I can't find any leaks in the bags and the compressor doesn't have any problem raising the car back up to Level 2 then I'm thinking that the valve that controls lowering the car after someone gets out is probably sticking open. I am assuming this based on the fact that it really only does it when it has to account for my weight in the car (260lbs) and not my wife's (maybe 140lbs) and that it only does it on the drivers side of the car.

I read on another forum of people putting a little air tool oil in the intake line for their compressor and it working wonders with the compressor and valves. However several people warned that it may work at first but it will do more damage in the long run. Does anyone know what type of long run damage could be caused by putting a few drops of oil into the system? Would it damage the compressor, the valves, the sensors, or even the bags? I was thinking that since my compressor seems to be fine (no noise and builds pressure fine) that instead of putting the oil in the intake side of the compressor that I would put it in the output line instead.

Any thoughts or comments on if this might work to free up what I think are sticking valves would be greatly appreciated.

[G0to60]

To really track down what's going on you're going to need to hook up VAG-COM and see what's going on. One other thing you may want to consider is the level sensors. Are you have any issues with your headlight leveling as well? Again, this is just guessing until you scan for codes.

[MK13]

Thanks for the response

I'm not having any issues with my headlights leveling and my suspension will cycle through all 4 levels with no problem and it appears to be level at all settings. It also raises and lowers to level when I get in and out or if I put a load in the rear.

I don't have a VAG-COM yet (I know, Lame) but I plan to get one soon as I have some other intermittent issues in other areas of the car that I need to diagnose.

[bagpipingandy]

the air bags only show leaks at level 1 could this be the reason? they don't leak when at level 3, due to the way the bag folds and the cracks open,

I don't recommend oil in the system, it is designed to be dry running, oil in the compressor intake will oil the cylinder but NOT go through the silicon drier, oil after the compressor will go into the valve block but the wrong oil and valves will stick, if working ok leave it alone, the corner sinking is almost always a leaking airbag, park at level 1 and see if it sinks, if it does to confirm a leak spray it with soapy water (rub all arund the back and mainly lower half) and look for bubbles only when the car is sitting at level 1 again

regards

Andy

[MK13]

Thanks Andy,

When I checked it for leaks I set the ride height at Level 2 (where I leave it most of the time) and locked the suspension in jacking mode so I could jack it up and pull the tires off. I didn't find any leaks in the bags using soapy water in a spray bottle to soak the bag pretty good. I will try again this weekend with it set a Level 1 and see if I can find something.

It's really puzzling because it really only leaks down after I have driven the car but not after my wife drives it. After I drive it, it leaks all the way down in a short amount of time but when my wife drives it, it almost never leaks down and sometimes it sits for days at a time before she drives it again.

[G0to60]

When you took the wheel off to check for leaks did you jack up that corner to have the air spring fold over itself? Usually the leaks happen at the folds and will "close" up the leak when the spring is extended.

Kind of weird that it only airs down after you drive it.

[MK13]

I jacked it up at the frame so the suspension was extended.

Yeah it is weird, my guess is that when my fat butt gets in the suspension on the drivers side has to air up to level the car out and then when I get out it has to air down to once again level the car and somehow the discharge valves are getting stuck and letting all the air out.

That's just a guess though.

[bagpipingandy]

My 1st thinking would be it is not the driver but more the level height the car is parked at. I was guessing maybe your wife drives & parks with it at level 2 or 3 and do you choose level 1, could this be possible?

anyway to check for airbag leaks, jack the corner up, spray the airbladder with soapy water rub all around the back with your hands, mainly spray the lower half & around the fold up under the shock, put the wheel back on the ground, and MOVE THE CAR so it sits nicely at level 1, leave it for 5-10 mins like this, re jack it up and inspect for bubbles, use a mirror to look around the rear of the bag, it will not leak with the wheel off the ground as the rubber airbladder is extended & not sitting in the same condition as if the wheel was on the ground,

another test, park it at level 3 it should not leak, but park at level 1 it should always leak (if a leak), I understand your thinking of the sticking valve too, but it is very hard to diagnose cheaply this is a good starting point and more common.

good luck! :)

best regards

Andy

[MK13]

Today when I parked it I'm pretty sure I could hear the front bag leaking air so I think I should be able to find it pretty easy now.

[MK13]

On Saturday I was able to find the leak in my front left air bag.

Here is the method I used to find it; hopefully this will help someone else. **Please don't drop your car on yourself while performing this procedure. Caution should be taken and I don't take any responsibility for YOU working on YOUR car**

1) With the car set at Level 3 and in jacking mode.

2) Jack the car up enough to get the wheel off with the Factory Jack (or floor jack if you have two)

3) With the wheel removed place a floor jack under the lower control arm at the knuckle from the front of the car.

4) Lower the factory jack until the car is resting on the floor jack placed under the control arm.

5) Make sure the car is stable while resting on the floor jack and completely remove the factory jack from under the car.

6) Lower (or raise) the floor jack until the center of the rotor is at approximately the same height as the the center of the rear wheel.

7) Start the car and take it out of jacking mode.

8) Lower the car to Level 1 (or you can cycle through each height level until you find the leak)

9) Spray all around the bag really well with soapy water. If you have a leaking bag you should be able to see it now. Don't forget to check the air lines and fittings.

10) Once you have verified that you have a leaking bag, raise the car back up to Level 3 and lock it in jacking mode.

11) Place the factory jack back into position and support the weight of the car on it.

12) Remove the floor jack and replace the wheel.

13) Lower the car while making sure your lug bolts are tight.

14) Now you get to figure out how you are going to be able to afford the shiny new Arnott GenII bags you really wanted anyway.

I couldn't find the leak in my bag without lowering it down to Level 1. On Level 2 & 3 my bags don't leak ;however my front bag is leaking so bad on Level 1 right now that you can actually hear it very clearly and I have to pull up on the front fender to get it to air up past Level 1.

I did the same procedure to my left rear bag and I still can't find a leak in that one so maybe the suspension controller is just leveling the car out when the front bag deflates. I'm still not really sure that is the case though because my issues started with my rear bag and have only recently migrated to the front bag.

[moretownmac]

Is there a specific level that it's best to leave the suspension at when parked for a few days in the interest of maintaining the good condition of the bags? I would think that all the way up or all the way down would mean more wear. Does anyone know?

[ModBargains.com]

Glad you were able to diagnose

[G0to60]

Is there a specific level that it's best to leave the suspension at when parked for a few days in the interest of maintaining the good condition of the bags? I would think that all the way up or all the way down would mean more wear. Does anyone know?

I personally leave it at Level 3 for longer parking lengths. The bags aren't folded over on themselves so there shouldn't be fatigue at the folds but they aren't at max pressure of Level 4. It probably doesn't matter too much but that is my thinking.

[AllWorld]

I know I'm yrs late here but what would cause my 02 Allroad to raise and not lower. Can't level. Jacked it up to do control arms and when done it raises fine then goes into fault because it can't level or lower. Front is lvl 3 or 4 about 18" from center wheel to wheel arch rear is about normal for lvl2. Can't get it to go down. Codes for limit surpassed...

[AllWorld]

Output test I can hear each block activate to lower but nothing happens. Accumulator tests good. Compressor works to raise. Not sure if air won't release at compressor or at valve block. Power is going to compressor release valve but I don't hear any movement when power is present. No bag leaks. Bags and compressor are from Suncore. Haven't replaced valve block yet but don't want to if that's not the problem