Audi Experts chime in

Builds
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Not a build. But since this thing has been a time/money whore since day one. It just might qualify. Anyway. if it does not fit the criteria. Mods, feel free to move.

Anyway. 03 Audi Allroad 2.7TT. Still has the factory pneumatic suspension. Front bags have been changed with Arnott, rear bags have been replaced with ones with significantly lower mileage.
The compressor has been rebuilt and its dryer cartridge refreshed. The Pneumatic solenoid valve block is original. The compressor will raise the car (while stationary) to any height I want. Run for a little bit and then turn off.
Now here is my boggle.

During cooler days (mostly in winter but recently it happened this morning) The front end of the car was on level one (I always drive and 99% of the time only use level 2). Typically its the rear passenger side that drops, but as of a few weeks ago, its the whole front end. Regardless of temps. I mostly see this when the car sits at the airport for a week or so, but recently it appears to happen over night. Ive gone over the whole system externally and cannot seem to find a leak anywhere.
Here is yet another piece of the puzzle.

When I start my car up in the morning to warm it up. The suspension will level its self out within seconds, regardless of which corner or end had dropped over night. The compressor will run as needed, and I can visually see the voltage arrow drop slightly as the compressor runs (observable amp draw). Once the compressor shuts off, the car can sit there at idle all day, and the compressor might come on for a few seconds once every 10-20 minutes.
Once I start driving however, the compressor will come one almost like clock work once I hit 10mph, and stay on for almost the whole time im driving. As long as the car is moving, the compressor will stay on. But here is the weird part. The compressor appears to be operating unloaded. What I mean by that, is that it actually sounds like its just free wheeling without producing any pressure. Also if I take my car out of gear and coast (engine at idle), the voltage gauge arrow does not move down at all like I would typically see when the compressor runs loaded. The car stays level while I drive as well. So yeah. Im a little stumped.

Any suggestions or advice? You know, besides the whole “put a match to it” suggestion lol.

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  1. you definitely still have a leak. Do a real comprehensive leak test on all the bags and fittings using a soapy water solution. If you want to dig deep, put jack stands under control arms so the suspension is still loaded. Remove wheels, try leak testing at different level settings.

  2. The compressor re-ring kits don’t always fix a failing compressor. I think bagpipingandy is selling cylinders also. Not sure. I still need to build mine. I also have difficulty “getting it up” when it’s cold out.

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I already did #1 twice. But may do again just to make sure.

I picked up the ring lot from bag pining Andy and it made a huge and noticeable difference. So I’m assuming the compressor cylinder is good(plus it didn’t use a single scratch on it). But I’ll look into a replacement cylinder and ring kit. I was pretty happy with his product.

I was was trying to figure out how the whole pneumatic system works. Please correct me if I’m wrong. But it appears that the compressor feeds the storage tank through the distribution solenoid block, and then the tank routes the air to each bag through the block. As for lowering. As far as I can tell the bags vent through the solenoid block and out of the compressor?

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Sorry for the grammar errors. Apparently auto correct hates me.

4

Any chance you have Vag-com? (if not I know its FS on here) you can monitor Compressor, compressor temp, and air pressure… it will really help point in a specific area.

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I had a handful of times similar situations of constant running compressors even after a rebuild. Each time a new compressor resolved the issue. I think the electric motor gets weak over time and isn’t making the power or RPM to recover as quickly as the computer is looking for.