Help! My 1975 F-100 gas tank has a leak! - Ford Forums

Fords Only · 11-01-2003, 06:39

I would be very grateful for any and all information that would assist me in removing the old gas tank (nearly full of gas for now anyway) and replacing it with a new one. The truck has 2 tanks - the rear one is the leaky one (the main ?). Rust is not an issue - it only has 28,000 miles on it! Thanks for your help.

351w · 11-01-2003, 08:12

any idea on why your tank is leaking.
is it a new style plastic tank?
first thing you have to do is get that gas out of there if the leak is that bad that it needs immediate attention.
if not drive it around for a few days as usuall till its empty and keep in mind that when the gauge says its empty you will probably have about 5-6 gal still in it.
removal is pretty simple once it is light enough to move around and hold up while you remove the straps.
you also have to disconnect the hose on the filler neck of the tank and then be careful not to pull out wires that are on top to the sender or pump.

Fords Only · 11-01-2003, 09:35

Thanks for the reply 351w! The tanks is original. The tiny hole is just above where the spare tire was hanging - I have no idea what caused the hole. Can you give me detailed info on possible tools needed, possible pitfalls etc. Thanks!

351w · 11-01-2003, 13:02

i have found it possible to do this job without any special tools as i have had both of my tanks out atleast once if not more.
it is a pretty cut and dry job but it doesnt hurt to have someone there to help lower and raise the tank in and out.
i have used a floor jack before to lower and raise the tank but be aware that if something isnt available to hold the tank it will want to tip off one side or the other as the leftover fuel splashes around inside.

simply disconnect the filler neck hose and get that out of the way.
then start to undo the holding straps and finally start to lower the tank.
when the tank has been lowered enough to gain access to the top simply disconnect the fuel lines and wires.

tips.
1. label each hose as to where you removed it from, so they are put back on the same way.
2. carefully watch the filler neck hose as this tends to be a pain to clear everything if you pinch it hard it will partially collapse the inner vent tube which will not allow you to refill the tank at a high rate of speed (you'll curse that later at the gas pump when it takes 10 min to fill)
i suggest taking as much of the filler neck off as possible before you try to lower the tank to prevent this.
also try to look in the neck as you start to remove it and mentally note where the inner tube is inserted.
you will see the neck is divided into 2 seperate passages.

with any mechanical abilty at all you'll be fine.
its not a hard job to do !
any problems just post back and i hopefully will be able to help out.

Fords Only · 11-03-2003, 05:39

Thanks 351w - you're a huge help. I'm still having problems with the siphoning - I can't get the tube to go in more than 15" or so. Any ideas?

89F150 · 11-03-2003, 19:23

I dont htink you can siphon, i think theres a theif mechanism thing? If you siphon it can be a b1tch to fill up because you can knock one of the fuel lines off. i know from experience. Can't you just drive around and waste it that way

351w · 11-03-2003, 20:24

well if you are having trouble sticking the hose into the tank either one of 2 things is happening.
1.you are coming up against the metal divider in the neck of the tank.
2.there is a metal spring type hose deterant in the filler neck.
i think that would only allow a couple inches of access.
what you are describing as being 15" in would be about the edge of the tank so your only choices at this point are to use a smaller tube or take the 3 screws out inside the gas cap door and take the filler neck hose off from the back and then you will have direct access to the tank neck.

Fords Only · 11-05-2003, 09:23

Thanks 89F150 and 351w! Unfortunately, the tank is still nearly full and I can't drive it around due to lack of insurance (it's a death/title/license issue). I will try taking the filler neck hose off.

Fords Only · 11-24-2003, 09:27

Thanks to all who helped! I finally got the right tank and finished the job yesterday.

89F150 · 11-24-2003, 18:48

nice work