Unlike many other manufacturers, the Ford Motor Company engineers developed a special retaining clip in order to hold the fuel lines in place. While more common variations of automotive fuel lines resemble compression fittings used in plumbing systems, Ford's feature a flared end that spreads into a housing that can be locked in place once the clip is inserted into the side of the housing. As with any speciality part, it is best to use a speciality tool to remove it. However, if you are careful, you can remove a Ford fuel line with a pocket screwdriver and some patience.
Access the head of the clip in the side of the fuel line end housing.
Place the tip of the fuel line removal tool around the head of the clip and release the clip, then carefully pull the fuel line away from the filter. If you do not have a fuel line removal tool, move on to Step 3.
Place the tip of the pocket screwdriver between the head of the clip and the body of the fuel line end housing. With extreme care, pry the clip outward and away from the fuel line. Once the clip is removed, carefully pull the fuel line away from the filter.
The retaining clips are made of plastic and break very easily. If your fuel line is more than five years old, or the line has not been removed in that time span, spend the money to pick up a fuel line removal tool. In the event you break the clip, you will need to buy a new fuel line, as the clips are unavailable separately from the line.