Quote Originally Posted by hubblaz12 View Post
checked airbags with soapy water and can't see any bubbling there ... compressor is buzzing but don't know if pumps air or not ...
If the problem has gradually been getting worse then the two most likely explanations seem to be a slow leak that has gradually got faster or a compressor that has become inefficient because air is leaking past the piston ring, i.e. the problem Andy's recon kit is designed to solve.

When you say it starts at the lowest level do you mean it sinks to that level when parked from some higher level? If the car sinks when parked that suggests a leak somewhere - if not the air bags then somewhere else. Remember that all four corners sinking doesn't mean that all four corner leak - one can be leaking and the control unit lets the others down to keep the car level. So, if your sure it's not the air bags leaking what about the pipework?

The general approach is fix leaks first, then sort out the compressor if that is not efficient any more otherwise, if you do the compressor first, you can have the compressor go bad again trying to compensate for the leak.