The fuel lines on a Toyota 4X4 pickup run from the engine, underneath the truck, to the fuel tank. These lines go from soft lines made of rubber to hard lines made of steel. The steel lines underneath the truck can fall victim to salt on the roads and the elements, rusting out the line and making it unusable. To fix the problem, you can replace the rusted fuel line.
Open the gas door and open the gas cap. Crawl underneath the Toyota and locate the fuel line you want to replace. Trace it to the connections on each end, and spray the rust penetrating spray on the fittings connecting the steel line to the flexible line.
Disconnect the rusted fuel line from the flexible fuel line with a line wrench. Pull the fuel line off of the plastic clips securing it to the frame and then remove it from the truck.
Install the replacement line in place of the rusted one, and push it into the plastic clips on the frame. Reinstall the fuel lines to the flexible lines with a line wrench.
Start the engine and look for fuel leaks on the connections. If you find any, tighten up the fittings with a line wrench.
