I'm replacing the front (side) tank on my 86 F150 (longbed)

I found a really clean used one from an 83..

Yup, I realize they're different (sending units, the way it looks) but my sender is rusted in place, so I'd be buying a new one anyway..

I'm assuming, since the instrument clusters were identical for 80-86, it will be a matter of attaching the old wires to the new sender.. However the plugs to attach the senders don't match, not even a little..

SINCE it's just a "rheostat" (variable resistance) circuit.. Does it really matter which is "positive" and which is "negative?" I can see the one "pin" on the connector is essentially just a stud, connecting to the metal flange.. The other goes TO the resistor..

I really don't feel like cutting the old one out of the tank, but if it's deemed necessary, I'll break out the sawzall, and hope it doesn't spark.. Any ideas for getting the rusted one SAFELY out???

I was considering filling it with water, since it won't be used for fuel again.. Will that help, or just make a mess??

AJ RN

 

You can do one of 2 things to make it safe to cut. You can fill it with water and let it run over for a bit to get the fumes out or you can run a hose from the exhaust of another vehicle into the tank and let the car run while you are cutting. The car exhaust gas displaces the oxygen in the tank thereby eliminating the possiblity of an explosion or fire. That is what we did most often when we had to weld a gas tank.

 

Well..

I didn't cut the old sender out..

I did a "test light" check, and found pulsing voltage in a blue wire with a yellow stripe.. The pulsing thing made sense, after a "what the heck" moment.. It senses every few seconds, or so, to make a more consistent reading.. (sure) It was freaking my poor digital multimeter out, as the range was all over the place.

The sender for the '80-84 has threaded terminals (thank GOD) so I put a #8 brass nut on the positive one.. Sadly, they're too close together to put a nut on both of them. (they'd touch) so I'm taking a metal hose clamp, and attaching the "ground" (neutral, actually) to the "feed" tube, so I don't have to cut, using a metal hose clamp (ugly, but effective!)..

Now, if I can just figure out where I left that lock ring, I could put the tank back up!

Cya..

AJRN

 

Thanks for that tip. New to me.

 

Okay..

The deed is done, it functions flawlessly..


That said..

Anyone wanting to replace a tank from an 85-86 with one from a 80-84 will need to consider the following..

1) you will absolutely HAVE to replace the sending unit, they're not even a little interchangable between the two tanks..

2) you will have to re route the fuel line a little bit.

3) you'll have to rig up SOME sort of connection from the factory harness to the new sender, as the plugs aren't compatible either.

That said.. At least in my case.. It was a good alternative.. I was going to have to replace my sending unit, anyway, the tank was $35, versus over 100 for new..

It's not undoable, and is an option..

...on that note.. Anyone got a REAR tank??

...yup, that ones rusted and leaking too..

Now that I've got the truck running, and ONE good tank, I've drained that one..

It'll come down soon.. Maybe it will be something I can patch..

The front tank was like patching holes in swiss cheese.. The real "killer" was a leak in the seam between the top and bottom halves..

Just a note.. JB Quik makes a great "cover" over conventional epoxy patches.. I'd use that again..

JB weld, however seems to degrade, over time, in the presence of gasoline..

Hope this helps someone else..

AJ RN

PS I've got a side by side picture of the two tanks, but couldn't figure out how to add it here..