I am trying to learn what I can about my newly inherited Class C. Every time I walk around it, I seem to find something new. Well, today when I was changing out the plates to make the rig legal, I found that the bolts holding the plates on were actually air valves for airbags in the shocks. My dad was a meticulous note taker, but I cannot find anything about this. When I throw a pressure gauge on them, there is no reading. I have no idea what the psi should be. I know virtually nothing about the suspension. Anyone have any advice?