Greetings everyone! I searched for this topic but couldnt find much on here but Im sure someone has done it.

I am a new owner of a 86 F150 Bullnose with 5.0. With the common issue with the dual tanks and them bleeding off or siphoning into front/rear tanks, I want to rid myself of any future issues and either bypass or delete one tank altogether. Has anyone done this? Is it as simple as finding a single tank "reservoir" off a Bronco or something and unplugging the sending unit/pump from the tank I plan to delete?

I just dont fully understand how these dual tanks work with the selector switch under the dash and the reservoir under the frame. How does it switch? Just cut off one pump at the tank?

Any info on this would be appreciated, and pictures would be awesome!

 

All kinds of info on the reservoirs here.

To do a one tank conversion, I bought a new one tank reservoir. They are still available. Simply replace the old reservoir and hook up the tank you wish to use. No wiring to fool with. Just toggle the tank switch to the tank you choose to run.

Of course, after reading and understanding the information presented in the primer linked above. I ended up keeping both tanks for now and have no issues with them.

 

They make a drop in 38 gallon tank for our trucks. spectra f26d is the right tank if you can find one.
Rockauto just had them back in stock (and the most economical), broncograveyard has them also. LMC as well iirc.
In the process of installing one into my truck.

 

Just note you have to move the spare tire to the bed or it hangs down really low under that 38 gallon tank.

IIRC the issue is the reservoir that has the tank switching valve in it.
Fuel pressure from the tank moves the valve to close off the other tank. Over time the valve gets sticky and not fully close the other tank and you get the working tank filling the non-working tank.
OR
Is it check valves in the intank pumps that are bad?
Dave ----

 

Just purchased the truck and honestly havent had enough seat time in it to know of the real problem or to properly diagnose it. But the previous owner just said that the "front tank doesnt work". Id drive this truck maybe 2000-3000 a year so I really dont need both tanks or the possibility of issues to keep both. So in the future, I will diagnose if there are any issues present with bleeding off or siphoning to the "off" tank. In that event, I'll then make a decision on whether to keep both tanks or just utilize running one tank for now.

@diggerrigger, I accidently popped into your build thread on your truck. Very detailed work! I'm impressed! Havent made it all the way through the build but I'm glad to know I could PM you for some of your insider knowledge, along with plenty others Im sure.

 

Don't believe everything you read in that thread. Everything in it is the best knowledge I had at the time but, in review, I see there is some erroneous information in some of my posts. I really should go through and clean it up.

 

Yes, when you get time to check things out you may find you just need a new pump in that tank.

 

Drove the truck a little last night and tried to put some gas in the rear tank since thats the "only tank that works". Noted both fuel levels before the fill up and the drive. Pretty sure it is bleeding the fuel return into the front tank. After trying to put gas in the rear tank, it would only take 4 gallons. So either the sending unit is way off, or the vent is stopped up to not allow but a small amount at a time. But after driving for a bit, I did notice the front tank reading more fuel in it than when I left the house. So Im believing its bleeding into the front tank.

 

i have a 86 Lariat 5.0 with duel tanks as well. You should be able to test the pumps to see if they are coming on. Years ago I had a problem with my rear tank return line being stopped up that forced the return fuel back to the front tank causing it to overfill. I also had to change out the 6port selector/reservoir valve about a year ago because like stated in a earlier post the valves started sticking causing the same issue. Just a word for the wise though, if the front tank hasn’t worked in a while it’s probably full of rust and crust that you don’t need in the rest of the fuel system.

 

I just ordered a single tank reservoir to just go ahead and delete the front tank. As you mentioned above, I'm sure the front tank is full of trash/rust so I planned on deleting it anyways due to that. I planned on pulling the bed off to pressure wash everything and make it easier on removing the tank so once the reservoir comes in, I'll be jumping on that pretty quick.

 

do you ever plan on putting a front tank back in?
if not I'd love to get your tank strap brace, I think it's called a trusset/gusset If it's in decent shape of course.

 

I ran my front tank for years with the rear just empty and the tank selector switch set to "front". When I rebuilt my motor I decided to run out of the rear tank and removed everything associated with the front.

dustyroad I still have the metal front tank straps if you're interested.

 

It isn't the straps I'm after. It's that gusset piece the strap (T) connects to on the outside frame. Without it, the straps are pointless.
Not a huge deal, they are the same up to 96 I just need to track one down at a junkyard but I'll gladly recycle someones from the forum.

 

Are you talking about part 9065 in the picture below? I thought that was a important gusset for the frame and not a optional piece? In other words, all trucks have them?

 

I dont know about important besides the support of the tank strap, I'm sure all trucks have them.
we had this conversation a few months back about it. You or fuzzface? was able to get one from the junkyard. That's where I learned it's the same up to 96.
I haven't made it there yet, many other issues to deal with first.