2003 D3 A8 3.7 Quattro.
Hi. With as much trouble as these air suspensions cause as they get older (judging by the amount of threads), it's funny i can't seem to find any answers to this (unless my symptoms are normal and there isn't actually an issue)....
When my car is off, all wheel arches are the same height from the centres of the wheels (give or take less than half an inch)...even when i check in the morning, after the car has been off overnight. There are also no lights on the dash and no fault codes stored. In the MMI, all four modes illuminate when going into air suspension options (lift, comfort, auto, dynamic) and switching between lift and dynamic causes no noise and is smooth. As a side note, as a recommended preventative maintenance procedure, I bought a new relay for the system, direct from Audi for about £17.50 and installed it today.
But for the past week or so, I've noticed something when driving (I've had the car about 2 months and it may have always been there, but it has been noticeable to me for the last week or so). Occasionally the compressor will make a quiet noise (the noise a running generator makes) for 5 to 10 seconds, followed by a short Pssst! Again, not very loud. The main times i notice it is when coming to a quick stop.
Since it makes the normal compressor type sound, i thought this to be normal (it is a compressor, after all), unless experts can suggest otherwise...I thought it best to ask since this is my first car with air suspension...better safe than sorry. And the sound of air releasing, I guessed is just the pressure regulating, especially when i come to a quick stop and more weight/pressure is applied abruptly to the front dampers.
So like I said, I'm just checking to see if this is normal behaviour, since this is my first car with air suspension.
Also, if there was a leak in the system, would it store a fault code for that?
Furthermore, there is a piston repair kit for the Wabco pump/compressor available from a Scottish chap (www.bagpipingandy.com - i have no affiliation with him) where you get a new seal for the piston ring and new rubber o ring and screws....its in the region of £30 and comes with clear instructions. ..doesn't look too difficult....but is this the only part to swap in order to keep the compressor running without issues? (Provided the mirror isn't completely knackered of course).
Thanks v.much.

 

As an update if anyone sees this. After finding some similar posts, I've found some people say when the compressor gets noisy, the piston ring should be changed and you should check if the motor/pump/compressor shaft (i forget exactly what you call that shaft) has any play in it. The only other thing i remember people said to check was if the compressor bolts are tight (the 3 bolts that secure the compressor).
Now for a start, i don't think bagpipingandy can help me here since i have checked the compressor and i have a "Miessler Automotive air suspension compressor aggregate" whereas he does the kit for Wabco. Anyway, does anyone have any experience with the Miessler brand? The manufacture date is 24.09.2015 so it has obviously been replaced not long before i bought it (approx a couple of months ago).
The only other label on the compressor states (probably part number, and such):
3Z 0101 1000
SCM80
12V.

What i did find was the bolts securing it were a little loose. I have tightened them a little now....will check it for a while to see what that's done (if anything), and update this thread again in the hope this helps someone.
I know there are are many threads out there but i just feel a lot of them have certain details that help different people's cases. So it's worth mentioning my experience with this. And if anyone has more info that i haven't learned yet, I'd be grateful for the input.