I have done multiple searches - tough to keep it all straight.

Any comments, discussion, advice?

My truck is a 77 F250 with 460 and I'm not sure what to do regarding my rear tank. I think some things were home jobbies b/c I have a toggle switch on the left side of the dash to switch the gauge btwn tanks.

My rear tank has had probs since Ive gotten the truck. Never been operational. I did not make much headway so I took it to a mechanic I know. He said he did some research (talked to a Ford "guru" he knows) and my rear tank is supposedly original. It was some upgrade option according to him. It is black plastic - can barely see a number on it. Well, my sending unit disintegrated when he took it out. I bought a sending unit off ebay on his recommendation but it is not the right one. It is physically too short.

We agreed to go with it b/c we could not find the correct sending unit. FYI a section of the filler neck was damaged while taking it in and out. Well, next problem truck stalls out and wont restart. It is no gas from the rear tank because the sending unit it too short. If the tank is not really really full (over half) there is no pick up.

Not sure what to do next, what would you do?

1.) I could repair the filler neck and use the rear tank while constantly keeping it quite full

2.) To hell with the rear tank and just use the small front one.

3.) Mechanic says he can find a steel tank and the correct sending unit to make it right.

What would you do?

 

replace it with a bronco 2 tank.

 

If you don't need the range, simply pulling the rear tank and running on the front is an option.

Otherwise, I'd go steel which is probably what your new sending unit is made for. On mine I pulled the rusty/dirty front tank and put a new steel tank in the rear. I only wish I went with the 38 gallon model instead of 19. I know the dual tank setups are part of the history of these trucks but they are also a reliability problem. Two tanks to get dirty, more rubber lines plus valves and switches.

 

OK thanks guys.

Whomever has replaced their rear tank, which tank/sending unit did you go with?

 

I went with OEM. I bought way back when, before it was NOS. There are still some available. If you decide NOS let me know and I'll locate some for you.
If you decide to go aftermarket check the tube size. Originally the tube that the line connects to is 3/8", a lot of replacements are 5/16".

 

77f250.... is the 460 original? Whats the frame width? There are two different frame widths. The wider one is fine, lots of aftermarket tanks available. Plastic tank is only like $140, replacement galvanized steel from napa for $99. Narrower frame rails and you will need a plastic tank from an 80's F350 chassis cab (not reproduced btw) or you'll have to move the frame rails or use a custom mount for a bronco II type. Or just measure and go to a junkyard and start hunting around.

If its wide I'd go ahead and swap a new tank in. If its narrow I'd definitely work with what you have. The sending unit isn't very complicated on those trucks, you should be able to easily lengthen or shorten it with tubing and or pipe.

 

I used an AZ tank and re-used the original sending unit ('78 F250). No problems.

 

Yeah, well a 78 f250 will use the wider frame rails. The only trucks with narrow frame rails, as far as I know, are the "high boy" trucks with in cab tank and divorced transfer case (and low pinion front axle), the F350 2wd of all years, the F350 chassis cab (which was 2wd all years except 79, and I think thats about it? I'm not an authority on the subject.

 

Why didn't you just fix the old sender with parts from a good one ? I've fixed a lot of them over the years. Whatever it takes, they are pretty simple.

 

Thanks everyone.

It is a 77 highboy, divorced transfer case and narrow rails.

Good call on lengthening it with tubing. Thats what Ive done. New problem now, neither gauge working. Maybe instrument cluster voltage reg. Oh boy,...

 

are the senders grounded properly? You can do a search on here for 'testing fuel sender' or something, you measure them with a multimeter and manually move the float to make sure the sender itself is working properly. most of the time its a bad ground, from what I've seen.

 

does your high boy rear fuel tank have a skid plate/shield around it? ...if so it may be a stock tank from a 2wd ..similiar to the one in my crew...plastic tank w/ metal shield....may consider selling the tank/shield and internals....

 

yes, it is the black plastic tank with the metal shield around it. I just need the sending unit, tanks and shroud are fine.

Got my gauge working for my small front tank but rear sending unit (which I know is not the right one) I cannot. Going to live it (rear no gauage, front guage OK) unless I can find correct sending unit someway.

 

did you test it?