Re: Pump and lock air ride ?
I have owned four air spring equipped Panther cars, one for almost 20 years and 400,000 miles. I have never seen a leak anyplace other than in the air springs (bags), although I'm sure it's possible.
The valve can be removed from the air spring, but it would requires some fabrication to get a Schrader valve to fit. I think that it would be easier to replace the air springs with an Air Ride or Firestone bag, or steel coil springs.
Regardless of which you use, no air springs are air tight, and you would want to install a remote fill valve to avoid crawling under the car to check pressure and to inflate the air springs.