1976 240D fuel lines

I'm reassembling a 240D engine and i have a line from the big fuel filter I dont know what to do with. there are three outlets at the top of the filter. one goes back to the tank, one to the injector pump and the third has me stumped . I cant find anywhere it could go. Ideas?

That third line is probably for the return line from the injectors. You know, the small rubber lines that go from injector to injector.
Bill Lewallen Lexington,Ky.

My 240 finally spend enough time in the driveway so I could take a look (three driving daughters!). If yours is a 115 chassis like mine, here's the layout:

The hose at the bottom of the filter goes to the end of the injection pump rack. The side port near the top of the filter goes to the connection by the hand pump on the injection pump. At the top of the filter is the main line from the tank, and it is tee'd into two smaller lines; one going to the right-mid side of the injector pump, and the other going to the daisy-chained injector return lines.

Hope this helps!