The fluid is filled to the proper level to accommodate the shaft and piston.
The shaft and piston assembly is pushed down into the tube and additional fluid is added to make sure there isn't any air in the assembly.
The top nut assembly is pushed down and secured with its retaining clip bleeding all of the air out of the main tube.
The shock shaft is pushed all the way down to its maximum displacement level to confirm the correct amount of fluid has been added.
Next, its time to pressurize the shock with nitrogen. The fill valve is removed from the bottom of the shock body.
Nitrogen gas is injected to 150 psi. The nitrogen will pressurize the fluid and prevent it from cavitating and foaming. Foamy oil does not provide proper damping function through the valves!