Today I replaced the fuel filler neck on the Excursion. It was a pretty simple but dirty job with this winter weather. The first time I filled the truck up I noticed the smell of gas. The second time I paid more attention and noticed fuel dripping down the leaf spring while I filled it. When I looked under the truck I noticed that the previous owner had sprayed rubberized undercoating all over the filler neck so I knew there was a problem with it. For anyone else that is thinking of doing the undercoating trick to stop a leaky fuel filler neck...It doesn't work. Just replace it for $150 and 30 minutes of time.

Tools needed:
8mm socket
Screwdriver

Parts Needed:
Two hose clamps
Fuel Filler Neck - I bought mine from eBay for $130 shipped: Fuel Filler Neck New 2000 2001 2002 2003 Ford Excursion | eBay

Here you can see the old filler neck, completely covered in undercoating. A failed attempt at a cheap repair. Typically the filler necks on the gas models rust out where the two pipes come together. Dirt and water collect there and rot it out. This one failed further up, where the pipes connect to the rubber hoses. Not uncommon, but not the most common failure point.



The first step is to crawl underneath. The Excursion has a big lift and tires but I still lifted it some to have room to sit up and work in the wheel well. Once under there you can follow the filler neck from the gas door to where it meets the rubber lines from the top of the tank. You need to undo the two hose clamps and slide them out of the way. Once those are removed you need to free up the hoses from the pipes. The small pipe is the vent tube from the tank. The large one is the actual filler tube. I used a screwdriver to pry the hose gently off of the pipe. Be careful not to destroy the hose or pull too hard on it. If you break it free from the tank or destroy it you will need to drop the tank to fix it. If the hoses are badly cracked or dry, it is time to replace them and you need to drop the tank. Do not attempt this repair if you do not have time to replace the hoses as well. I got lucky and the hoses were good.



Once the hoses are loose, head up top and take off the gas cap. Plug the filler neck with something so that dirt can't fall in. When you are pulling it out from under the truck you can knock dirt into it, down the tubes and into the hoses. You don't want dirt in your fuel system. Once plugged, take off the three 8mm screws holding the filler neck to the body. It will hold itself in place once they are taken out so don't worry about dropping it. Wrestle it out from underneath the truck. Do not pull too hard on the hoses from the tank.




Here you can see the new fuel filler neck next to the old. This should solve my problem. The old one was so rusty that part of the vent tube broke off inside the hose. I used needle nose pliers to twist it out, again being careful not to damage, twist, or pull the hose from the tank.





Time to put the new one in. Plug the top again so that nothing can fall into it. I found it easier to set the top in place but leave the screws loose, then head down under to align the hoses. Put your hose clamps on the hoses before attaching the new fuel filler neck. They were on the hoses in the phot but they had slid down past the frame so you can't see them. Use some lube on the filler neck to help make it easier to insert into the hoses.



Once the bottom is lined up you can head to the top and tighten the three screws into the new filler neck. Unplug it and reattach your fuel cap. Make sure everything seats properly.



Once that is done, tighten up the hose clamps down below and go wash up.

 

Nice write up - thanks for posting!