Only thing that comes to mind on a push on fitting is that the hose is cut at an angle to were its not sitting flush! Cut it strait as you can with a razor! I would not recomend cutting air line hoses with side cutters, they leave a V cut and can cause leaks. Also use a spray bottle with soap and water to check lines,fitting and also the air bags for leakage also!!
On the schrader valves! might want to check the valve to see if its seated properly too! Local auto store should have a tool that tighens them also