Another A8 Air Suspension Question

[Fairyglass]

I've just become the owner of a 2003 4.2 A8 and have an immediate problem I hope you can help with. My front nearside tyre is completely flat, and the car is sitting so low that I can't get a jack under it. I've found the jack mode and tried this, assuming it would raise the car, but it doesn't. I've set the suspension to lift and this also hasn't raised the vehicle enough- in fact it sits higher on Auto. I've solved the initial problem by driving onto a block to raise that wheel but going forwards I'm guessing there's an air leak in the system. Having searched I see there's issues with seals, and I need to solve this to prevent compressor burnout, but I don't know where to start. Is there a step by step test guide that I can use to isolate the issue? Or do you experienced people have tips for me to check initially?
Thanks in advance

[A8Cruiser]

Hi Fairyglass,
how far did you get with this?

[Crasher]

Jacking mode does not lift the car, it stops the system from reacting to the car being lifted.

[JohnF]

A bit late, but this reply might help others with similar problems. My 2005 W12 sport quattro also developed a leak. To diagnose where from, park it in Jack Mode and observe. Jack mode means it will not wake up, sense the imbalance and try to level itself, wasting air from the accumulator. (I assume a knowledge of SSP 292 'how the air suspension works' - if not, google it). In my case it was the driver's side (R side for USA readers) front strut, which took two days to bottom out. Next, to diagnose where the leak is, open the bonnet and carefully slide back the two rubber caps on top of the turret, exposing the top nut of the strut. Pour in a little soapy water (use washing up liquid) and look for tiny bubbles. If none, paint the soapy water around the strut underneath. Usually, a slow leak like mine is a failed top 'O'ring. A failed bag would leak much quicker. In my case I slowed it by putting industrial strength sealant into the top of the turret and belatedly always leaving it in jack mode with a wood block under the front jack point. That saves air loss and prolongs compressor life.
Alas, too late to save my noisy fifteen year old compressor which failed completely a couple of weeks ago. I sent off for a 'bagpipingandy' kit (again, google it if you haven't heard of him) to recondition it thinking I could do it myself. Sadly, although the compressor can usually be accessed behind the front wheel arch this is not the case for the W12. The front bumper must be removed which was beyond my capability. So I have just got it back from my indy who has expertly completed the task. As the leak is small, shows no sign of getting worse, and as I only drive it two or three times a month, I have decided not to expensively replace the strut.

[A8Cruiser]

Did you replace the pump solenoid too?

[JohnF]

No.

[A8Cruiser]

Worth replacing.
it’s a £5-10 relay sits under the carpet where the front passenger would put their feet. ����

when I bought my 8, I had the garage change it.

[JohnF]

Thanks, but I subscribe to the aphorism 'if it works, don't mend it'. I know there is a remote possibility of its contacts fusing together so the compressor runs till it overheats but I keep a small spanner next to the battery to disconnect it if that happens.