Hydraulic lines should never be constructed of

Hydraulic lines should never be constructed of galvanized pipes.

Explanation:

For best piping, the pressure loss should be minimum among the hydraulic lines.

The galvanized pipes are pipes that are coated mostly with zinc for the prevention of corrosion. Galvanized pipes should never be used for piping as the coating of zing might erode or flake. More pressure will be lost in such kind of pipes.

The best material to be used for hydraulic pipes is mild steel. The mild steel will not have any coating that will erode with time.