1978 Ford Bronco 25 gallon fuel tank swap in J10!

[msh227]

I have been doing some research and finally found a 25 gallon tank that will fit where the stock tank was. I couldn't find any thread on here of somebody doing something similar, maybe I just didn't know where to look for it. I liked some of the ideas about putting a 30+ gallon tank behind the rear axle but I didn't want to move my filler tube hole on my bed so I decided to try this idea.

I got a replacement 1978 Ford Bronco 25 gallon fuel tank from MTS Company. I don't like how the stock tanks were strapped to the bottom of the bed so my plan is to attach this new tank in between the frame. It will make it nice when I have to remove the bed for body work and paint. I'm using square stock as my frame for the tank and bought 1/8"X 1-1/4" steel for the straps. I plan on welding 7/16" bolts to the end of the straps in order to recreate standard fuel straps. The straps will be bolted to two cross members that will lay on top of the tank and hold the tank in place.

Here are a couple pictures of the fuel tank mock I was able to complete tonight. I picked up the needed material and got all pieces cut to size. On Thursday I'll complete the installation.

Only thing missing in these photos are the straps.











I will place a piece of 3/8" steel across the opening in the cross member for the square stock to sit on.

[FSK1460]

I was considering using one of these tanks on my Grand Wagoneer down the road. Was curious, what model sending unit are planning on using? And does is register correctly on your gauge? I thought I read somewhere the ohm readings were different depending on model.

[msh227]

I actually bought the sending unit through MTS Company. It sounds like they make their own sending units, I'm assuming they replicate the original sending units that Ford used. I was told when I ordered the tank that the ohms are the same and it would work perfectly. Hopefully that is helpful.

There is only one downside to the sending unit MTS Company had available. I will need to shorten it because it is a sending unit for the Ford Bronco's 33 gallon tank. MTS doesn't make a 25 gallon sending unit but this will fit with just a little minor trimming.

[flyusmc]

FSK1460,

When I swapped my 32 gallon Bronco tank, I swapped out and used the stock 88 Wagoneer sending unit. It had to be bent a bit to register normal, but it works just fine.

-FLYUSMC

I was considering using one of these tanks on my Grand Wagoneer down the road. Was curious, what model sending unit are planning on using? And does is register correctly on your gauge? I thought I read somewhere the ohm readings were different depending on model.

[FSK1460]

FSK1460,

When I swapped my 32 gallon Bronco tank, I swapped out and used the stock 88 Wagoneer sending unit. It had to be bent a bit to register normal, but it works just fine.

-FLYUSMC



Did the Wagoneer sending unit mount in the same? I know they have the big nut that screws on top holding it in place, but looking at the pictures of MTS's tanks, you can't see any threads for one.

And what exactly is the "EMS" hole for? Looks like you can buy some tanks with or without it.

[threepiece]

I have been doing some research and finally found a 25 gallon tank that will fit where the stock tank was. I couldn't find any thread on here of somebody doing something similar, maybe I just didn't know where to look for it. I liked some of the ideas about putting a 30+ gallon tank behind the rear axle but I didn't want to move my filler tube hole on my bed so I decided to try this idea.

I got a replacement 1978 Ford Bronco 25 gallon fuel tank from MTS Company. I don't like how the stock tanks were strapped to the bottom of the bed so my plan is to attach this new tank in between the frame. It will make it nice when I have to remove the bed for body work and paint. I'm using square stock as my frame for the tank and bought 1/8"X 1-1/4" steel for the straps. I plan on welding 7/16" bolts to the end of the straps in order to recreate standard fuel straps. The straps will be bolted to two cross members that will lay on top of the tank and hold the tank in place.

Here are a couple pictures of the fuel tank mock I was able to complete tonight. I picked up the needed material and got all pieces cut to size. On Thursday I'll complete the installation.

Only thing missing in these photos are the straps.









I will place a piece of 3/8" steel across the opening in the cross member for the square stock to sit on.

For some reason the pictures aren't showing but it seems you are welding two crossmembers to the frame and attaching the straps to them. I think Jeep mounted the tank to the bed floor to minimize the effect of frame twist. I am planning a custom fuel tank and am considering two brackets that are attached to one frame rail. The straps would then be attached to the brackets. This I think would help to isolate the tank and structure from twist.
Dan

[msh227]

Got the tank installed today and everything painted. I'm really happy with the way it turned out. Ran into one issue with the Ford sending unit. There is no return line/vapor line back into the sending unit. I'm guessing that is what it is for. The Ford sending unit only had the feed line no return line. Here are some pictures of the final setup.

[msh227]

For some reason the pictures aren't showing but it seems you are welding two crossmembers to the frame and attaching the straps to them. I think Jeep mounted the tank to the bed floor to minimize the effect of frame twist. I am planning a custom fuel tank and am considering two brackets that are attached to one frame rail. The straps would then be attached to the brackets. This I think would help to isolate the tank and structure from twist.
Dan

Let me get this straight. You plan on on running the straps around the entire tank and having it fastened on to the frame with the two brackets? Just trying to visualize your description.

[threepiece]

Let me get this straight. You plan on on running the straps around the entire tank and having it fastened on to the frame with the two brackets? Just trying to visualize your description.

Something like that. I plan on creating a cantilever design using two support brackets or arms if you wish, that will attach to one frame rail. The fuel tank will then be attached to those arms with straps in much the same way it originally was. By not attaching to the opposite frame rail, I believe I will isolate the tank and support structure from most of the frame twist. If you have a chance to look at a 1970's Wagoneer or Cherokee you will notice the front fuel tank mount is also of a cantilever design.
Dan