I discovered a leak in my rear fuel tank ('95 F150) which is metal. It is under the strap that holds the tank in place. There is a putty in this place and was oozing out the strap with a wetness that smells of fuel. I think previous owner used that leak stop putty. Anyway, I plan to drop the strap and peel off old putty (no scraper as don't want sparks, though possibly plastic bondo scraper) and place new putty. Was going to wait for tank to be nearly empty in case the hole is so big that I open up a fountain. I suppose it is worth a try, but if the leak is too big I may need a new tank. If anybody has done this before, I am open to advice/tips.

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Hello, well if you want to bother with quick fixes I'm sure you can find some type of sealer to fix it but personally I would just buy another tank. I'm in the same position as you exactly. I took my rear tank down on the weekend and have rot behind strap, although my tank is much older than yours it is only $126.00 for a new one. I would guess that there may be more holes developing in other areas as well. But its up to you.

 

my gas tank was leaking. we syphoned all the gas out into jerry cans. then we dropped the tank and had the hole soildered using a heated piece of metal and some really thick soilder. it held. still is holding. been about 5 years now since. the tank was just very tricky to reinstall

 

For $126 a new tank makes sense. What is involved in changing it?

 

Hello TallPaul,

Well the job may not be too bad for you being a newer 1995 but the biggest headache will likely be unhooking the main fuel line without screwing up the sending unit. If you can get the tank down at a slight angle towards the passenger side you can reach the connection. I hope the bolts that hold the strap come loose for you. Mine did after a small amount of heat from a cheap propane torch.

 

for me to change mine. i placed a jack and a block of wood to hol dit up. took off the brackets, then the fuel gauge senor and whatnot. kinda broke the gauge so it dosen't work well anymore. to put it in is super hard because of the filler hose. that was a trick to get back in. to take it off is esay, well on my truck anyway

 

I take it the main fuel line does not allow the tank to drop very far before the slack is gone. I'll replace the tank if necessary, but first I will pull the one strap off (I hit the bolts with some penetrating oil) and see what is going on. A co-worker said he fixed a leaky tank with liquid steel. May put a dab of that on and then the putty. I am hoping the leak came through the old putty due to age of the putty and not from enlargement of the hole.

Nice truck vampiro. My first truck was a '77 F100 short bed, flareside, 300 six with three on the tree. Oh that I had kept that truck!

 

thanks paul. for a temp fix try gum or zest soap on the leak. it's mnot permentent but for the time bing it'll work

 

Joseph, I recall reading once that bar soap will seal a small fuel tank leak. Saturday I pulled the strap off and found a large rusty area, but no hole. I wiped it down and waited and saw a small spot where the rust was getting wet. Apparently the rust has made it porous, but the metal does not give when I press it. I put a package of the fuel tank putty (says clean metal, not rust) all around the area and the hanger strap presses into the putty to help mash it down. Filled tank Sunday morning and so far no more seepage. Not sure how long it will last, as if I stick my nose right at the leak area there is a faint smell of fuel. Not bad though.

 

TallPaul, I'm glad to hear the putty may work for you.

In my 1993 I had a very similar leak. I changed out the tank.

Things to consider when changing out our tanks:

Of course, disconnect the battery whenever working on a fuel tank...

But:

Disconnect the filler tube from, first, inside your gas door... take the screws out. Then play with the hose's clamps. I really wish I woudl have known to order new hoses, and have them on hand when doing this, but I didn't and I had to get it done. There are two hoses, one inside the other, and I'd suggest replacing both of these. My outsdie hose was really deteriorated.

The fuel lines have those funky Ford connecters that need the X tool. Maybe you'd get a little more slack out of one of the lines if you disconnected it from the fuel filter, but this didn't hit me until just right now.

I think there's a vent line up there that needs to be d/c'ed also.

The wiring harness is another severely limiting factor that has to be carefully, and quickly, pulled off the top of the tank.

To drop the tank I had to unbolt and unhook the rear part of my exhaust. (Not take it apart, just unmounted it to move the system to the side)(maybe this was just to put the new tank in... I forget)

The twist ring that holds the pump and pickup in the tank can be pried / pulled out of its rusty holding place - you'll get a new ring with the new tank.

Carefully pull the pickup system out of the tank - don't want to damage the fuel level device.

With all the work that's involved for one person, and the hassle, I'd replace the fuel pump and put a new sock-screen on while I was at it (of course, again, I did mine at night and didn't get those parts replaced - and I'm not happy about it).

Installing the new tank: be careful about the fuel pickup - put it in there carefully. You may need another helping hand to push down parts of the twist ring in places (with screwdrivers or chisels) while you similarly push down other places and get it to twist into place.

Halfway in I had to use a hammer to knock in, or bend, a tab or two on the new tank to get it to clear and fit.

I hooked up my fuel lines without the extra outside-clips and it isn't leaking.

I really think, in an ideal situation, that if you have taken the bed off before and replaced those bolts, it might be easier and worth it to unbolt and lift the bed again to get at the fuel lines and wiring harness for both pulling it and installation.

So think about buying:
1.) the two filler hoses
2.) hose clamps
3.) fuel pump
4.) fuel pickup sock

 

i hope it holds for you. When i replaced my gas tank, i bought that undercoating asphault. sprayed the whole tank form the outside in it. so far no rust has been bubling out from it. so that's something to possibly consider

 

Thanks all. Still holding. Anyway it eventually will be leaking again, but the changeout is complicated enough that I will have it done for me. The undercoating sounds like a good idea too. Strangely, on this truck the front tank is plastic. I wonder if they make plastic rear tanks. Also, changing the fuel pump while it is down is a good idea. Well, hopefully I don't have to do anything for a year or so.

 

Oh yeah, the filler hose. I had to have the filler hose replaced on my motorhome (1990 E350). Every time we filled up the tank my wife would complain that the motorhome smelled of gas. The filler hose was all rotted and because it is nearly horizontal with the top of the tank, when filled up the fuel would sit in the hose and seep through. This hose was really wedged up in there and a pain to get at.