An improved method of forming a trenchless flow line is provided. The method includes support of the boring tool at each sight relief hole using a hook extending downwardly into the hole so as to overcome the force of gravity on the tool during the pilot hole drilling step. Then, a back reaming tool is connected to the end of the boring tool, and the pipe is connected to the reaming tool, such that the reaming tool reams the pilot hole to a larger diameter ahead of the pipe, which is pulled through the hole with the reaming tool. Drilling fluid is supplied during the reaming process to form a slurry which is pushed ahead of the pipe and upwardly into the sight relief holes, as the pipe is pulled through the reamed hole.