Hello everyone, I've got a possible problem with my fuel sending unit and want to ask for some advice.
Maybe to help me figure out what the path of least resistance is...

2 days ago I was in the truck heading to a garden center, happy that she was running as well as she was. Then, as if the the universe wanted to remind me to not get too comfortable, I lost power completely.
I drifted onto an off ramp, tried to start her up a few times...no luck. Primed the carb, eventually got her started again. Drove about 1/2 mile, then she conked out again for the day.
I called AAA, they sent a truck and towed it to the mechanic that swapped out the carb for me 2 years prior.

A few hours go by and the Mechanic calls and tells me that we ran out of gas. My gauge said 1/2 tank.
I went to pick it up, his guys did a few basic things, blew out the fuel line, put 5 gallons in for me, etc.
Before I drove away, I tried to fill the tank up...a LOT of fuel started flowing out of the top of the sending unit.

WTF? The gauge was then showing empty.

Here are some factors to consider.
-It's a 1985 flareside F150. Single tank, inline 6.
-The sending unit is only about 2 years old. The original float on the sending unit was replaced to a hard plastic type, the original deteriorated very quickly (I assume the thin brass cannot handle today's gas).
-New fuel filter up by the carb.
-When I replaced the original fuel sending unit, the original float hadn't worked properly for about 15 years (my dad never bothered to fix it and kept a mileage journal) I had the flareside bed completely disassembled to replace rotten bed wood, rails, etc. so replacing the fuel sending unit was pretty easy. Now the bed is fully assembled and it doesn't look so easy. There isn't much room to operate in there any longer.
-The filler neck hose was in very bad shape and some critter chewed a hole in it, so I found a suitable replacement and wrestled that into shape.
-ONE THING I NEVER REALLY GOT RIGHT, was the other little corrugated hose that sits inside the fuel filler hose. I believe it's to let air out so gas will flow in faster. It's a real pain in the *** filling it up, the pump constantly shuts off when the hose fills up and slowly releases into the tank.

*One other thing that I never considered but feel I should include here...there originally was a metal line that ran off of the tank, along the back the cab and up to the engine compartment off of the passenger side rail. That whole line deteriorated sometime in the 80's. I think it goes up to a charcoal box up in the engine compartment.

So, I need to figure out what is going on with this fuel system. To do that, I'd imagine I need to drop the tank?
I've never done that before, would love advice on the easiest way to do this.

Thanks in advance, please let me know if I've left out any info.

 

Re: The new leak from the fuel sender. Did your mechanic touch the sender at all? If so, it seems they didn't get it sealed properly. If not touched, perhaps it has been like this the whole time but maybe you had never had filled the tank quite so full, especially if the fuel nozzle kept kicking off early.

Details here, on page 99, for testing the sender:

Fuel Tank Selector & Gauges (Gas) - Gary's Garagemahal (the Bullnose bible)


Dropping a tank is no fun, but doable. Siphon out as much fuel as possible to reduce the weight. If not sure how to siphon, just park anywhere in Oklahoma and somebody will take care of it right away for you.

Cut a piece of plywood roughly the size of the tank. Use this with a floor jack to support the tank. Hook up a pair of motorcycle straps to the frame, looped under the tank. The straps are to keep the tank from tipping off the jack.. Leave a couple of inches slack. With the jack and plywood supporting the tank, unhook the mounts and lower the tank onto the motorcycle straps. Repeat the process in small bites, disconnecting the wiring and plumbing as you go.

 

Oh yeah, one more thing. If not in a hurry, visit a self-service car wash. Get underneath the bed with the spray wand and go to town. Then park in the sun and let everything dry for a few hours. This will really cut down on the volume of crud falling on your face while working under the truck.

 

The truck runs fine correct? And the tank is definitely full. I would run it some and keep a mileage log like your dad did till you get some of the fuel out of it. Then drop the tank.

 

The truck runs fine correct? Yep, she runs fine'ish. She pooped out on me while I was on the road the other day and she's usually a pain to get started. The carb usually always needs a shot of go-go juice...which you helped me out with a few weeks ago BUT, once she's started and running and warmed up, she usually runs pretty well.

And the tank is definitely full. I would run it some and keep a mileage log like your dad did till you get some of the fuel out of it. Then drop the tank.
So, get her as empty as possible and then drop that sucker, see what's going on?
It's the original tank, I would imagine there is all kinds of stuff floating around in there. Do you think it would be worth it to get a whole new tank? They're only like $80 on LMC and I'd know I have a fresh clean tank...maybe it's a waste of $$$. I dunno.

Do you have any thoughts on that deteriorated fuel return line from the engine compartment, down the rail and back into the tank?

 

Haha, it's all new under there (body, bed, frame, etc) for the most part...so hopefully it's not that bad!

 

Or run the tank dry and flip to the rear tanks ------ sorry thinking of my flare side
Carry 5 gallons of gas and run the tank dry and dump in the 5 to get you home to drop the tank.

I had the rear tank new sender stop working so I ran it dry before I dropped it.
If you can it is easier if you can remove the bed. In my case with fresh paint and unlike the style side no easy way to lift my flare side bed I had to dropped the tank.
I also have a rear class 3 hitch that was part in the way and in dropping the tank think I hurt the inner plastic tube as I now have issues when filling.

You are right about that metal line going to the charcoal box under the battery.
On the tank it goes to a roll over valve / vent also on the top of the tank.

Across from the filler next to the frame cross member is the roll over valve. It should be turned to point to the cab so it can hook up to the metal line across the back od the cab.
I replaced the roll over valves and the rubber grommet for both tanks so they would not leak.
As you can see I used HD straps to hold it up in place to get the factory straps in place.
Dave ----

 

A new tank on one of these trucks is never a waste of money. Every Ford I have owned so far except the 84 Bronco II I have has needed a new tank. Even my diesel tank started leaking. A clean fuel system does wonders for making the engine reliable.

That line did go to the charcoal canister, it was a breather line for the tank. If it's just hanging under the truck now, there is danger of dirt and water entering. Anywhere you run it, you will get a gas smell as the fuel heats up and expands in the tank. You could plug it completely if you drilled a hole in your gas cap. Or you could hook it back up to the canister, but you really should hook that back up so the engine will purge it, or you will get a gas smell under the hood.

 

I’m gonna let the picture do the talking here...



Seriously...what the hell is going on here?

I decided to pump a bit out of the tank to see what I could see...this is what came out.

gas on top, god knows what the hell that stuff is underneath.

what’s my best course of action here?
drain whole tank?
new tank?

 

I would get a new tank. ( ) and new straps just to make your life easier. Before you put it in I'd read up on some of the articles here about filler tube vent hoses and decide which way is best for you. Side note, i'm not sure how often you use your truck, but if it tends to sit for periods at a time I strongly suggest avoiding using ethynol.

 

Thanks for the advice. My vent hose was the worlds largest pain in the *** to install. And I’m sure I did it incorrectly because the neck would fill up every 15 seconds when filling. I’ll look into that more tonight.
I’ve got a new hose, so not worried about that.

How do you avoid using ethanol?

 

We have fuel stations that sell non-ethanol fuel. You could also try a boat marina, I think I heard they sell it also. That is all I run in my small engines. I got tired of rebuilt carburetors every season.

 

Yeah, I live in a smallish town with two gas stations, both here have non-ethanol blends. I do know that the walmart gas stations (at least around here) only offer ethanol. I'd say just look/shop around, i'm sure theres probably something you can find. Right on the pump there are stickers that say 10% etc.

 

Adding my 2 cents worth...NEW TANK!!!

 

Typical of US gasolines when they get old. The crud on the bottom is oxidized additive package and fuel. The U.S has this propensity to add oxygenators to the fuel, and this has the added benefit of speeding up the oxidization of the fuel and the additive package and corroding the tank.

I have never had to replace a tank due to extensive internal corrosion here, the odd pin hole from water sitting in the bottom, yes, complete internal tank corrosion no...