Audiheavy

First off... I've read enough about this issue from this forum and others that I refer to it as the "War and Peace" of D3 air suspensions, as well as the many videos on the subject (thanks mostly to Mr. Louis). And yes, have pulled the codes. This is more of a mechanical issue as I'm trying to go about this in a step-by-step process. Initial symptom was the very typical, collapsed front right shock. I then set about rebuilding the offending shock and after watching and reading further, along with close physical examination, was surprised that there's only 3 possible sources of a leak... the small o-ring at the top of the shock shaft, the large o-ring at the bottom of the housing sleeve, and the airbag itself. I remain somewhat convinced that actual airbag failures are quite rare and after careful inspection determined that mine was intact. I want to emphasize that these are simple o-rings... not triple-sleeved, ceramic coated, exotic seals from either German elves or NASA. So, after careful assembly with new o-rings I still have a collapsed front end. I then went about following the VCSD process of "charging" the system as the car had been "resting" for a while. All 3 channels (Basic Settings) responded; 8.78 bar on the accumulator, 4.56 bar on the front axle and 6.51 bar on the rear axle. Can anyone share the acceptable charge pressure ranges for these 3 components? The compressor pump works fine and raises the rear of the car with no issue, but I get the common 01583 "leak detected" code. I know, I know... it's now crawl-around time with soapy water and hope for the best, but I think this is a hit or miss proposition at best... report to follow. I'm really interested in hearing from people who have had success with changing out these magical o-rings. I believe "Tstealth32" recently posted that he was "2 for 2"... but don't know if he meant 2 failures or 2 successes?

As an aside, this reminds me of D2 ownership... as the D2 cars aged a very common problem became the number one forum topic, transmission failures. Probably 75% or more of all D2's would end up needing either a rebuilt or new transmission and fortunately for us, the D3 has a very robust unit with very few failures. But as we collectively read more about these suspension issues, as a function of age and possibly mileage, I suspect virtually 100% of all D3's (and certainly other "bagged" cars) will experience a failure in this area. So to those of you who have yet to experience this... gird your loins.

... and then there's the MMI screen gears :-)

Cheers!

Tstealth32

I'm 2 for 2 on success rates. It's worked for some people I've sold orings to, and had failed for others. Just depends on the strut.

Giovanni Giovino 6.0+6.0TT

Hello Audiheavy,
You forgot the brass fitting that feeds the air into the bag itself, it has an O-ring and a rubber gasket, those have leaked and are available for replacement, next would be the airline connection at said brass fitting, these 2 areas along with the 3 areas you stated would be the 5 areas of leakage possible on a strut, then the connection at the other end of the airline to the valve block, the valve block or the airline itself.
What I have done in the past to prove that the leak is or is not the strut itself, or not the airline or valve block, is to get a piece of airline and some fittings as shown in attached picture, and attach that short piece of airline with air valve right at the strut and fill it with air to proper height and let it sit, or even go for a drive to test for droppage, if the strut passes I then reinstall the factory airline connection and add my air valve fitting to the factory airline at the valve block end to test the airline in the same manner, fill the strut and test.

.

Audiheavy

Hi G2... thanks for your insight, missed those 2 additional areas. I like your idea of a test... report to follow.

Audiheavy

A brief update... thanks to G2's suggestion made a simple test connector, worked like a charm, thanks!


So here's where I'm at:
1. Replaced all O-rings in the valve block connections after one "looked" like a possible leak from the Mr. Bubble test.
2. Pumped front right shock with adapter, no apparent leaks. Installed on car and loaded front right with weight of the car, all good. Connected shock to green air line from the car.
3. First bled then charged the system according to Vag-Com; Accumulator: 9.44 bar, Front Axle: 9.44 bar, Rear Axle: 6.51 bar.
4. Started car, switched off Jack mode and put it in Lift mode, everything lifted accept front right.
5. Disconnected green air line from offending shock and attached my test kit. Used my compressor to pump it and it's holding the weight of the car fine.
Assumptions:
1. Pump appears to function within parameters.
2. No apparent leaks in offending shock.
3. Possible bad valve block or bad airline (green) from VB to front right shock? Leaning towards the VB as the culprit. There are 6 valves in it: compressor inflow, accumulator, front right, front left, rear right and rear left. Is it possible for just the front right valve to go bad?
As always... thanks in advance.