This angled fitting connects two sections of fuel line where a change in direction is required within the fuel supply circuit. It is installed between the fuel tank outlet or filter housing and the rigid or flexible line leading to the injection pump. A worn or leaking fitting introduces air into the fuel system, causing hard starting and erratic engine operation. The fitting is machined to match the original port geometry and sealing surface, so the banjo bolt or threaded connection seats correctly without additional sealing compound. On reinstallation, ensure the O-ring or copper washer is replaced and the union is tightened to the specified torque.