Taylor Lewis

Hey guys I'm new to this forum! I got an 2004 A8L (4.2 V8) a couple months ago and have been fixing it up a little ever since (random little sensors, brakes, etc.).

I have been searching all over the internet and forums for answers and seem to be getting closer to the problem I'm having with the Air Suspension, but decided to post here and see if anyone might know whats going on, as I don't have the usual yellow and green suspension lights that usually accompany air suspension problems.

Problem: The passenger front side is usually always a bit lower than the driver side (noticeably by about an inch, though sometimes it will even out randomly). When I bought it a couple months ago it would raise into all 4 modes no problem (kind of surprising as it has 160k) it just started acting up a month ago. I have since jacked it up a couple times (in jack mode, except for the first time) to do brakes and to figure out a "tinking" noise (gave up on that, probably the upper control arms or wheel bearing/hub where it connects). I'm wondering if I could have damaged something the first time by not putting it in Jack Mode? Anyways, I've scanned in VCDS and the only code I have gotten is for the common "Over Temp for the compressor." I've changed the relay as I've read that it can get stuck, however I've never heard mine running after I turned the car off, just did it as a preventative measure.

After about 500-1000 miles of driving this is the only code that comes back BUT it only shows itself when trying to get into "Lift" mode. If I don't try to put it in Lift mode then I don't get this code (I've done plenty of scans for the fault code and the code only shows itself right when I select Lift mode and wait. The timing for the code/fault in VCDS is in line with me selecting Lift Mode. I've also driven for 2-3 weeks in comfort and rescanned and there are no codes). I'm sure the compressor is somewhat worn but it still pumps decently, everything goes to normal levels besides the passenger front.

I've done the Jack Mode procedure and the passenger front side was lower than the others when I went to check in the morning. I did the soapy water test to confirm and I was able to see small bubbles coming from the bottom when trying to go into Lift Mode, right below the rubber cover which leads me to believe its either the bag or if I'm lucky the O-Ring at the bottom. I don't have any yellow suspension light on, the only thing I've noticed is that while driving, usually while pulling up to a stop light or maneuvering into my driveway/garage, I will see the green suspension light come on in the instrument cluster very intermittently (sometimes for 2 seconds, other times for about 5-10 seconds and it seems to never linger, it just will come on for a couple seconds and go away). Sometimes at stops lights I also notice the front rising a little bit, I would assume trying to compensate for a leak? I haven't seen any codes though for a leak, however maybe its because its small. The green suspension light also comes on about 5 times more frequently when in Automatic, rather than Comfort (in City driving, I know it comes on when you are going 75mph+).

I've also done the suspension level calibration successfully as this was my first guess, thinking that it may have gotten out of calibration by jacking up.

Anyways, any help is appreciated, and sorry for rambling on! My first step will probably be the O Rings at the bottom but does anyone have DIY on how to do it or could walk me through it? I just don't want to further complicate things by going in blind. It seems like the rubber sleeve is quite tight when trying to pull up.

Tstealth32

I have the orings if you go that route. Basically you'll have to remove the bottom bolt, disconnect the air line and I believe lossen the top bolt so the bag can fully deflate.

Remove the boot by pushing it down.

Then push the airbag up so it shows the bottom oring.

Slip in the new oeing. Lube it up. Pull the airbag down back over the oring.

Slide the dust boot back up and use a large hose clamp to keep it in place.

Put the bottom bolt back on. Tighten the top bolt back up.

I'm pretty sure you'll need an air compressor and hose attached to the strut to get enough air pressure in there to seal everything up. Then you can screw the factory hose back in.

Taylor Lewis

Hey tstealth32,

I didn't see your last message, I figured I'd wait and see if things got worse and they have. The front passenger side is really low in the mornings now and it takes 20-30 seconds to pump up. I'd love to try the O-rings from you before anything else, just let me know what info you need from me and how I can pay you!

In regards to changing them I have a few more questions. Do you pull the dust boot cover up from the bottom or down from the top of the strut? It looks like there's a clamp on top but I've read from another thread that someone "pushed up" the boot. Also, instead of loosening the top bolt, could I just wait till morning when its dropped to jack it up to change the orings, that way all the air should be out?

Sorry for all the questions, I really appreciate your help.

Shark_V8

I pushed tire sealant into my leaky strut. Put in a about 8-10 oz. I used a sealant without big chunks. Had to remove the brass fitting and make a fitting to screw into the strut body.

Took a few weeks of driving but it sealed it up. No drop now.

Jack88

In my case, the upper o-ring has failed. I have a pretty clear failure of the bubble test, it drops in minutes. It went very quickly. After an unrelated issue brought it to a shop, I think they lifted it out of jack mode and the strut went to full extension and that did something to the already weak seal, because it went from being fine before they had it to dropping relatively quickly after they had it. By the time I got to working on it 10 days after I figured out it was the strut and had stopped driving it, it would lose height in 3 minutes from lift mode. If you want to test the o-rings and the bubble test is inconclusive, I might suggest shrink wrapping some plastic around the bottom of the dust guard and dampener and some more on the top of the strut around the wire and 41mm nut. In theory, the plastic would blow up like a balloon until it burst if you had an o-ring leak there. Just an idea from an idiot, never tried it, but I think it would probably work.

Taylor Lewis

I had bubble coming from the bottom so I just replaced the bottom o-ring but with no luck. Once it gets in lift mode in keeps going up and down and after leaving it over night its on the ground by morning. Unfortunately I'm just going to get a new one. Not sure if I want to spend money for an Arnott strut, eBay has some for around $300 but I am worried about the quality though.

Jack88

Sounds like a failed bag, then. They do make rebuild kits, they aren't difficult, and are cheaper than Arnott or a used strut. I can't say if they are more or less likely to fail than Arnott's(who have had reported quality issues) or a used strut(an obvious gamble.)

Taylor Lewis

Yeah I was looking at the rebuild kits but I figure its easier to get just get a new one and put it in. I don't wanna deal with soldering the wires back at the top and I've heard that 41mm nut can be a pain. I got 163k on my A8 so a new strut, even if less quality, wouldn't hurt. I think I may go the ebay route, only thing I worry about is the quality and whether or not it has the electronic dampening but at $280 with 2 year warranty it might be worth the try. Next up is Suncore at 470 but it looks like they just buy their new ones from China anyways and mark them up.

Jack88

The 41 mm nut is very easy, provided you loosen it while the strut is still installed in the car. If you wait until you have removed the strut, it's on there pretty tight and it's hard to brace the strut to remove it. A rebuild adds maybe 30 minutes to the job of replacement.

capbarbaruiva

Hello,

I have a 2003 A8 V8 tdi with 515k km (320k miles) and the suspension has been acting weird for a long time. Yesterday, it just refused to go up at the front and is extremely low. I can hear the compressor working but the front just doesn't move. I suspect it is the right passenger side as I had already noticed the left going up a few times when opening the car. Never checked the right side.

I looked everywhere and found only one post with general dimensions for the o-rings, 11x2mm and 57x3mm. Is it diameter? Inner or outer? 2 and 3 is thickness, that's easy.

For the old A6 allroad there is a kit available. Couldn't find it for the A8!

It would be nice to share correct specification for the o-rings as one could find it locally when needed.
I am from Portugal by the way

thx
Miguel