Romell,
By lazy axle, do you mean lift axle(pushers and tags)?
If so, you can Google "lift axle" and see how they are constructed. There are many variations in design from different manufacturers. Basically, they usually have 2 small air bags situated in the design that inflate with the control inside the truck lifting the axle/tires off the ground. Deflating those and inflating the suspension air bags will lower it to operating position.
If you are looking to get one for your build, GWtrucks, sold through sourkrauts, has a nice, multipiece unit in resin. You can also contact Gary at GWtrucks directly here. gwtrucks@yahoo.com