hi i have a 1985 f150 with dual tanks. the tanks{front and back} leak have rust and filler neck problems, i gonna replace the front tank and want to isolate the back tank but im not sure how any help or advice would be great, thanks

 

i do have a pretty good idea on how to pull the tanks just the iso i need help on

 

Do you have the EFI engine or carb?

First if it were me I would consider getting both tanks working. It's really annoying to have to fill up every 150 miles on a long trip BTDT.

Another option is to get the the larger 35 gallon rear tank but you would have to put the spare tire somewhere else.

To run one tank you will have to bypass the tank switching valve and run a new fuel line from the fuel pump to the tank. You can get the Ford quick disconnects for the hose ends or just use rubber fuel line and hose clamps.

If you can find the correct fittings it may be possible to bypass the tank switch with short pieces of tube and use all the existing fuel lines.

If you have EFI then you will also have to run the smaller diameter fuel return line to the tank. Splice before the switching valve or run all the way to the fuel rail.

Note With 1 tank you will have to keep the dash select switch always set to the correct tank for the fuel gauge to work. You could pull the wires from the switch and splice the correct pair together so it won't matter if the switch is accidentally turned to the missing tank.

You will probably need a new fuel sender and if EFI also an in tank pump. A new tank does not come with these.

 

i have a motercraft 2bbl carb and i thought i could just clean the fuel pump it seems to work fine and reuse it in the new tank i bought replacement for my year im assuming that it will fit? aslo gas gauge not working any ideas. thanks for posting!!!!

 

What engine size?

For the fuel gauge. Could be any 1 or more of these problems:
1. Dash switch set to wrong tank or broken.
2. Sender in fuel tank is broken.
3. Fuel gauge itself is broken
4. Wiring between any of the above items.

5. Some models have a motorized electric switching valve if so that... and associated wiring.... must be working as well. (Has a connector with 5 or 6 wires).

If you have the solenoid tank switcher (2 wire) then that will not mess up the fuel gauge working or not.

I could be wrong but I don't think the carb engines had the in tank fuel pumps? If the tank connector has 4 wires then you have the in tank pump. 2 wires then not.

 

its a 302 5.L, and im sure i need like all the wiring redone buts thats way beyond me, lol. im not sure on the pumps though, i'll know for sure on monday when i try my hand at pullin the tank. thanks for posting

 

I wouldn't expect allot of wiring problems unless there was a fire or someone has been 'hacking' on the wiring.
My '86 shop manual shows all 302 as EFI but I think '85 was the changeover year where some are and some aren't. Let us know what you find.

 

i have a carb and all i did was bypass the fuel pump and rear tank and put in an electronic fuel pump and inline filter and one hose going right to the carb from the tank if that helps

 

also when u pull the tank make sure its empty cause that will fall on you and they are a lot heavier then you think i had one land on my shoulder when it was halfway full and i swore i broke my collar bone

 

i thinks its my console wiring when i use my turn signals one brake light wont work unless i jingle the signal bar, left or right, and i changed the fuses, and as it turns out i cant iso back tank permanently because i live in California and it wont pass smog if i do so now i got fix both tanks but i can iso it till next year then fix it before smog. thanks for posting