A6 Allroad front suspension dropped, one side only

[mhobson]

Hello,

My wife took the car out today, smooth roads, came home. parked and after about an hour I looked out and saw that the front R/H suspension had dropped down hard on the tyre. It is a 11/2006 4F C6 3.0 tdi, earlier this year I had the rear suspension unit changed and about 35,000km ago I had both front suspension units changed (at great cost). The issue with the front units when I had them changed was because the car was tramping on a straight road, as if you were in a car with no shock absorbers. This is very different and If it has to go to a garage it will be a breakdown job. When I start the engine all 5 blocks of the height gauge remain empty, normally at least one is orange. This does not change on any setting between dynamic and lift, the car does lift a bit but not enough to steer the car without the tyre fouling the wheel arch. I have tried to hear if there is an air leak by putting one end of a plastic tube in my ear and moving the other end around inside the wheel arch, cannot hear a leak at all. The computer will not allow me to select jacking mode. This fault was sudden with no warning up until today since the rar repair it was running perfectly.

I await your comments,

Regards,

Michael

[mhobson]

Update:

I have left the car for a while, gone back turned on the ignition and two orange bars were illuminated, (set on dynamic), with engine started the car started rising and then there was a sudden short sharp air squeak from the front right and the car dropped back onto the tyre (pleased I didn't have my hand in there at the time), and the orange bars disappeared, no up or down arrow illuminated. I turned off the ignition and waited a while, when I turned the ignition on again the computer let me turn on the jacking mode, but with the engine running the white up and down arrows do not illuminate and the yellow and green car suspension warning lights are flashing. Cannot move the car because the wheel arch is resting on the tyre. It will be difficult to get a safe jack under there and see what we has, another problem is that it is parked on loose gravel which makes the car jack very unstable.

[Crasher]

Leaky bag, have bag will leak...one day. Arnot replacements are not worth the box they come in.

[mhobson]

I have no idea what Arnot replacements are. The struts which were replaced about 35,000 km ago came from Germany but that was not the suppliers name. The reason I changed the struts was very different to today. Tomorrow I hope to be able to jack up the car, remove the inner wing and try and locate an air leak.

[Crasher]

Struts are one part, air springs are another, were the air springs replaced?

[mhobson]

This has me very confused, I thought that the front suspension unit was one lump, which were changed only about 35,000 km ago. with an air line going in the top I did not know that the strut and air springs were separate. Where are the air springs located?

[Retrostyla]

It's same unit. Spring is around the shock and it's not some separately. Rear is different story.

[mhobson]

Have got the inner wheel arch out. Fault code 02646 on level control. When you turn the ignition on the compressor runs, the MMI shows the height with two bars orange, the car starts lifting and then there is a sudden pressure release near the compressor and the car drops, the MMI display changes immediately no orange blocks shown and if you look at the lifting mode it goes grey, you cannot change the settings and it shows lifting mode on, even when the lifting mode was off when the display was correctly illuminated. I have not been able to find any gradual leak yet.

[mhobson]

Seems like the strut again, after removing the boot it is easy to hear a lot of air loss coming from inside the top when the compressor is running.

[54A4Avant]

Hello,

My wife took the car out today, smooth roads, came home. parked and after about an hour I looked out and saw that the front R/H suspension had dropped down hard on the tyre. It is a 11/2006 4F C6 3.0 tdi, earlier this year I had the rear suspension unit changed and about 35,000km ago I had both front suspension units changed (at great cost). The issue with the front units when I had them changed was because the car was tramping on a straight road, as if you were in a car with no shock absorbers. This is very different and If it has to go to a garage it will be a breakdown job. When I start the engine all 5 blocks of the height gauge remain empty, normally at least one is orange. This does not change on any setting between dynamic and lift, the car does lift a bit but not enough to steer the car without the tyre fouling the wheel arch. I have tried to hear if there is an air leak by putting one end of a plastic tube in my ear and moving the other end around inside the wheel arch, cannot hear a leak at all. The computer will not allow me to select jacking mode. This fault was sudden with no warning up until today since the rar repair it was running perfectly.

I await your comments,

Regards,

Michael

hi Michael

leaking air bags don't usually collapse quite so readily and quickly, normally it's a more gradually overnight settling towards the bump stops. If the front air springs / shock units were worked on fairly recently (35k km isn't so much after all), is it more likely the air line to that one unit has become partly unscrewed and has a poor seal which lets go as the car rises?

how many km has the car done overall?

you might want to find the air line attachment point andput some soapy water around it, then try to observe with an inspection mirror and lamp to see if there's air exhausted from there when the car sinks. Likewise the air shock unit. The valve block for the air suspension is just below the passenger side headlamp (on a LHD car), right next to the compressor. That's another potential point for sudden leaking as the air lines are all plugged in there. You'll need the car on jack stands with undertray off to check it out.

Good luck.

[mhobson]

I thank you all for your help, now I have got the strut off the fault is very evident, there is a vertical split in the rubber airbag about 60 mm long. To me this is a surprising fail, up until my wife parked the car that corner had never dropped, not even with the original strut, the fault with that was the internal shock absorber. This split must have been sudden with no warning and I can only suspect poor quality materials or manufacture. They were not original Audi parts but were supplied from Germany with a 2 year warranty which has only recently expired, but even if it hadn't, my experience is that often the suppliers try to find some excuse to renege on the guarantee.

[Crasher]

£1500 each.... try these people http://www.ipd.de/ipd/produkte/11-luftfederung.php

[mhobson]

I posted yesterday but it has not come through, I got the strut out and it was easy to see a large vertical split in the rubber airbag of about 60mm, that corner of the car had never dropped before, not even with the previous struts, their problem was the shock absorber. It must have blown suddenly just as my wife arrived at home, very lucky it did not happen when she was driving at speed as the car body dropped hard onto the tyre, thanks to all who have contributed advice, Michael

[54A4Avant]

It seems very strange that a split like that suddenly occurs due to a latent manufacturing fault with the car parked up. Are you sure it hasn't been caused by a sharp blade, ie. malicious damage? You know how the French can be towards outsiders...

[mhobson]

Not a chance, the airbag is up inside steel cylinder, very difficult to reach or view until it was out of the car, keying a car would be a lot easier, I have suffered malicious damage in England but not yet in the last 12 years in France.

[mhobson]

I could not afford £1500 for genuine Audi, bought a new unit from Aerosus Germany, £608. Difficult fitting the unit, especially getting the lower attachment fork over the lower suspension arm even with the anti-roll bar link detached, but finally it was up and running with the engine running it was quickly up to height. Checked fault codes --- none. Guess what next morning the body had dropped down to the tyre again, just on that corner. My parking place is on a slight diagonal slope and the front right corner was at the lowest point so supporting more weight. When I parked the car the other way around with that corner at the highest point the suspension has not dropped. I have tried swapping several times and it happens the same, just at that corner, all other corners stay as they were left. The only air connection I had touched was the thin green air supply pipe to the strut and used new fitting and olive. In the garage I have sprayed the fitting with soapy water, no sign of a bubble, I can only assume that when under load there is a very slight leak within the unit. Aerosus who guarantee the unit for 2 years have offered to collect, test and replace it if necessary. Of course then I will have the grief of getting the strut out, waiting for a replacement and having to fit it again, and maybe if in testing Aerosus do not put it under sufficient load, they may argue that it is not faulty and return it but something that has to work at pressures of over 10 bar, it should be constructed to an extremely exacting standard. Woe is me! I am still using the car as I need it a lot at the moment and will have to wait a couple of weeks before I can take it out.

[Retrostyla]

What happens if you lift the car or use vcds basic settings to fill the bags to high pressure and leave it to jacking mode? Then you can see if there's minor leaks on high pressure.

[mhobson]

Did that could find no leak. did level control output tests, all OK. If I pump it up high it stays up longer but comes down in the end, still could not find a leak on the only air fitting I have touched. can only suspect a very slight internal leak on the strut, I just wanted it to do what it always did, stay at the same level on all wheels that it was left at, even if I don't drive it for a few days.

[allroading]

Hi, Did you ever get this sorted in the end. I have the same problem, a 2007 Allroad 3.0TDI (engine code ASB) and I park un uneven ground where the front right suspension takes the greatest load. Recently I have found that if I park overnight the front right corner is resting on it's bump stop.

[mhobson]

Yes, sort of. When I was looking for a re-placement strut there were many different sellers, and instead of going cheap, and I could not afford ridiculous Audi price I bought one from Aerosus in Germany. Disaster! the strut collapsed several times, was returned to Germany twice, then on a test run after the last return I drove a couple of miles and the strut collapsed to the ground outside a cemetery, I jacked it up to look at it, arranged at some cost for a recovery vehicle to come the next day to bring the car home, next morning some thief had stolen the jack. The bodywork was so low to the ground it was impossible to get the car on the lorry without damaging the bodywork. So firstly I would say, don't buy Aerosus. Then I thought looking at was available I would buy a Chinese strut, cost only about £200, fitted it which must now be over three years ago and it is still working but not perfectly. There are two main parts to the strut, the suspension and the shock absorber, suspension is fine but the shock absorber rattles inside the strut which is a bit annoying, also when the strut is working correctly the car height display should show the same height as when the car was last driven when restarted, but if it is faulty as the needle always goes to the top until you turn the ignition on again. If your car only drops overnight maybe there is only a small hole in the suspension bag and it may get worse which could be a big problem, there may also be a small leak on the brass valve where the pressure goes into the strut, if it were me I would spray a bit of soapy water on all connections to see if the leak is visible. There are some companies who sell parts to rebuild struts but that work is out of my league. I am toying one day with replacing the Chinese strut for one available on Ebay from Miessler Automotive in Germany. I have had parts from them before and they seemed reliable. Good luck.