Larry, easy to do:
Remove Tupperware. Follow the Schrader valve to a line. Disconnect it. Follow to next component. Disconnect it. When you get to the airbag, stop. Use Teflon tape, and connect the lines to each other so you have a Schrader valve on one end, and the airbag on the other. There will be a couple of connections. Put air in the bag. 45# will do. Put a capful of dish soap in a spray bottle, add warm water, shake. Spray all over bag and connections and lines. Leaks make bubbles. Meanwhile, measure from the tip of the rear fender to the ground. Write that down. If you find no leaks, replace Tupperware. When you do your weekly tire pressure check, measure the fender to ground. If it is down more than an inch, add air. I manage to lose a lot of air with my tire pressure gauge; the ruler is easier! My number is below. Call me if you need help. Joe