mishar

While a leak will kill the compressor for sure it will eventually die even without any leak. Lowering and lifting often makes it work overtime and shortens its life. If it is not building enough pressure (16 bar) it will work until it overheats. In the process it may burn the relay too. Only way to go is a new compressor. New relay is a good touch too.

Johnnyb2451

I have been driving my car all week with it riding on the lowest setting. It is back to only having the "lift" setting grayed out. I am guessing there is air left in the shocks or a reserve tank. I am planning on replacing the relay no matter what ($20 at Napa) and probably the compressor with a Mercedes one for $415, my friend said he can switch out the connections to make the Mercedes one work. Dont know why the same pump is less with different connections. It will take a week to come in so I hope my car will still be driveable. We will check the valve unit too. Would it be silly to replace the valve unit too if it seems okay? Thank you all.

mishar

I would not replace the valve unit if I am not sure that there is something wrong with it.

Mister Bally

The WABCO air compressor for a Mercedes vs. an Audi A8 has different orifices and produces different pressure. No need to worry as it will work. Suspension transitions and recovery will be slower. Save the money and use a Mercedes-Benz unit.

Johnnyb2451

*Update* Thanks guys. My car my air suspension mysteriously started working normally today for a few hours then quit working after we changed from automatic mode to lift mode and then would not go back up after switching to dynamic. We replaced the $20 module under the dash, the old one had one of the four prongs scortched? Anyway, it worked a few minutes after that and then quit working again after switching sport modes. Tomorrow we are going to check the right rear air shock leveling sensor as we noticed it was lower than the other corners. If that is okay then we are going to oil the valves in case they are sticking. If that does not work then on to replacing compressor I suppose.

mishar

I would suggest that you stick with compressor and relay. Check that relay again. If the new one is burned your compressor is drawing too much power. It could be motor. One of the magnets can get loose and create fiction. You can glue it back. If that is not a case I would buy a new one.

Johnnyb2451

Mishar, you are the best, thank you! I will let you know what we find.

Johnnyb2451

Today was a great day, suspension is working great. We had cleared codes with Vagcom Thursday and changed relay, and oiled valves ever so slightly with compressor oil Saturday. Suspension is adjusting perfect with no issues. Compressor looked fine. Hoping car will be okay for a while. We also changed wiper blades, cabin filter and changed oil. I always use Castrol Full Synthetic 5W40. My friend noticed oil leak coming from left (driver's side) valve cover gasket, he said he could tell it just happened recently. Gasket was $53 from autozone. Also, replacing both upper control arms, lower control arm, and sway bar link on left side. I am thinking they are bad due to not being replaced when right side bushings were replaced.

Mister Bally

I believe you have one of the motor magnets in the shell of the compressor motor starting to separate from the shell. It is dragging slightly causing higher current draw. Eventually, it will blow the "not easy to access" fuse below the steering wheel. Either replace the compressor or remove and disassemble it and re-glue the magnets using JB Weld.

Johnnyb2451

I see, I will do that next time I can get my friend's help. Thank you very much Mister Bally.