We have a 2007 Tiffin Phaeton with a Freightliner chassis that is losing almost all of the air in the air system in roughly a 24 hour period. We have had a Freightliner repair service in GA and a RV dealer in FL work on it. Freightliner in GA found a small leak at a fill valve, and they changed it. There was still a leak. We took it back to them. They couldn’t find anything else. The dealer in FL found some more valve leaks and a leak on an airbag. They changed a rear airbag, tightened the valves, and repaired small fitting leaks. We are still having the same problem. The air system does fill back up when the coach is running, and stays filled as long as the coach is running. Any suggestions?