This handbook to custom air ride suspension offers information, tips, and tricks on compressors, fittings, valves, water traps, air line, and road side repairs, at Sport Truck Magazine.

At this point you need to remove the nitrogen from the reservoir to depressurize the shock. Do this by simply pressing the Schrader valve just like letting air out of your trucks tire.

A few years later, August Schrader invented the spring-loaded air valve that bears his name and is found today on everything from car tires to suspension forks to department-store bikes.

The nipple-esque protrusions just below the gauges are Schrader valves for adding air pressure.