I worry about the age of my air tanks and rust. My bus is a 1966 MC5A and to my knowledge it has the original tanks. Should I be concerned? I fixed an air leak at a regulator (50psi) three months ago and had absolutely know idea what it's function was for. I removed the old one only to find out the diaphragm was like petrified wood and it had some rust flakes in it. It was a small regulator that I could not procure so I installed a larger one that I set for 50psi on the bench before installation. So good so far. It's location is just in front of the R/H rear wheel.
BTW the fella that I bought this bus from kept no maintenance logs. I know stuuuupid me bought it anyway.
I do drain the tanks once in a while.
If it ain't broke, dont fix it :D