Bronco Fuel Tank Mod

When I upgraded my Fuel System pick-ups and returns, and try to plumb a balance line between the front and rear tanks. I found out that the Broncos used a single 33 gallon rear mounted tank. With the combined capacity of about 38 gallons using the OEM F-series tanks, I figured I could loose the front tank, just have one in the rear and not loose too much fuel capacity. The down side is the spare tire won’t fit under the truck with the Bronco tank in place. It’s worth the sacrifice to me, as I have other plans for the space that was taken up by the front fuel tank.

Overview of Project:

The Bronco fuel tank is slightly narrower, a few inches shorter front to back, and twice as deep as the OEM F-series pick-up rear tank. I used the OEM top straps from my rear tank and modified the new bottom straps that came with my Bronco tank. The Bronco fuel gauge sending unit ohms the same as the F-350 so you just have to do some wiring splices and all is good! I made a new pick-up and return going into the tank, but I think the F-350 fuel lines would snap right onto the Bronco tank, though they may be a little short, I’m not sure.

Materials Used:

• New (used) Bronco fuel tank, 33 gallon capacity. I don’t think the model year of the Bronco matters, as it’s the 33 gallon tank you want.
• New bottom straps (mine came with the used tank). You could re-use the OEM F-series skid plate and just use spacers and longer bolts, but I thought the straps made a cleaner job.
• Fuel gauge sending unit from the Bronco 33 gallon tank (again, mine came with the tank).
• Misc. nuts and bolts.

Total cost of project varies depending on the cost of your tank. My total was around $120, not including primer and painting the tank, as it was a good used Southern unit (important for us Ohio folk.

Mounting the tank:

Trial fitting the Bronco tank. You can see the sending unit/pick-up is in roughly the same place as the F-series rear tank, just back a little farther. You have to pay attention to the location of the filler neck, too, as the Bronco tank is shorter front to back. Some simple measuring will show the tank needs to be pretty far forward.  Also, the F-series filler hose at the tank needs to be lengthened.

Permanent mounting of the tank. I added some rubber strips between the tank and straps, and the new Roll-Over Valve is seen on top of the tank. Part of the new Fuel System is also visible.

A photo of the rear of my truck. You can’t even tell the larger tank is under there.

Results:

I liked having the feeling of a sense of security with the two fuel tanks. But in reality, when you’re out of fuel, you’re out of fuel! The Bronco tank works great with the modified fuel system, gauge works flawlessly, and the spare tire is just as happy resting in the bed.

Happy wrenching.