I have been replacing the air bags in the rear of my bus and I have the bus up on Jon's stands. The other day I was working under it sit behind the differential when the for some reason I heard and felt air coming out of the one Norgren (I think the top one) and all three bags on the drivers side went empty. PANIC. But the bus didn't drop because of the stands. You never know what may cause the suspension to drop.

I could understand why the tags would dump air if the pressure got low, but all three bags on one side? The passenger side three bags were still rock hard. The bus is level on the stands so I don't think it has anything to do with the road leveling controls. Level selector was in Drive and the key was off.