Which of the following is not a required step during the pre-fill inspection?

Filling the cylinder with liquid is not a required step during the pre-fill inspection because the pre-fill inspection process is primarily focused on ensuring the safety and integrity of the cylinder before any filling takes place. This inspection involves checking for signs of wear, damage, or any conditions that could pose a risk during the filling process.

By inspecting for leaks, checking for bulging, and examining for cracks, personnel ensure that the cylinder is safe to use and transport LP-gas. These inspections are critical in preventing accidents and ensuring compliance with safety regulations. Thus, filling the cylinder would only occur after ensuring these safety measures are in place, making it distinct from the pre-fill inspection steps.