Rear underbed gas tank conversion

[MOPAT]

The reason I was measuring mine is that I am looking @ doing something similar during my build.
I had a 75 gal. 'L' shaped "fuel transfer tank" under my crossbed bed tool box. The extra weight smoothed out the ride considerably and it was
GREAT for BOONY CRUISING but 70 gal @ $3.50/gal got a bit out of hand.
Next time it will be ~30 gal with a few 5 gal 'Jerry cans' strapped down in the back when I go exploring.
One of the guys I know locally put a '84 Ramcharger poly tank in his 70 W100 SWB and seems real happy with it.
I'm going to measure up the tank in my '79 B200 van and see if something similar will fit. It is 39 gal, and sits between the rails.
I'd like to see some of your pictures as you progress..........
hanks
Pat

[surfnuke9]

The ramcharger tanks are almost the same dimensions as the bronco tank.

Main difference was availability. Couldnt locate a used ramcharger tank (that didnt look in awful condition) or a new one, and the new bronco tank I got was only about 140 bucks.

I plan to take some mockup pics this weekend.

[hampstead38]

GREAT for BOONY CRUISING but 70 gal @ $3.50/gal got a bit out of hand.
Pat

I didn't know it was cheaper to fill up a 35 gallon tank twice than a 70 gallon tank once.

[MOPAT]

ALL DEPENDS......on how much change you can find under the seat @ 1 time.

[hampstead38]

How about clearance between the tank and the exhaust? I was thinking about a rectangular tank between the frame rails with a fill tube in the bed near the rear wheel well. Heck... I could even do TWO fill tubes for those times I just too lazy to make one more turn. I don't want the exhaust too close to the tank... is a few inches enough? Or should I add some kind of insulation?

[JimE]

I went by a tank fabrication shop this morning and asked about putting one of the Ramcharger tanks behind the rear wheels. The response I got was "IT WON'T FIT", he says the frame is to narrow. That kind of put that idea out of my mind, what I'm still looking for is a tank big enough to go 350 miles with out stopping for gas and to get the 25 gallon tank out of the cab. Jim

[hampstead38]

Jim,

I'm not a math whiz, but I think the area that holds the spare tire has got to be about 33" across since that's about how tall my tires are. A tank that is 33" by 33" by 12" deep will hold around 57 gallons. Even if you shave the tank to 10" tall you get 47 gallons. I figure around 50 gallons should get you from hither to yon in most situations. And I don't think it can hurt to put that weight on the rear of the truck when the roads are a bit slick. I don't know if this helps, but I hope it doesn't hurt.

[66patrick]

The '69 - '72 Blazer tank is nearly a bolt-in, as well. It's 30 gallons and is available through a number of parts houses.

[moparbob71]

Surf, I used a 16 gal Jaz cell and custom made the fill- goes where the spare tire was.I test fitted a 71 RR tank and it fits great but since it's a center fill I didn't want to cut my new chrome bumper. If I can help just ask.Cya!

[jarheadsgt]

I did this in the 70s whit an olds tank, a big flat one I got from the county boneyard and strapped to under the bed where the spare tire rack was. I used anout as much banding as I could and it worked well. I never ran out of gas running cross country to my girlfriends house. I had to add an electric boost pump or it would suck the fuel out of the front tank first, and the rear did not have a guage. I had to shut off the boost pump when it started thumping on the rail, you could feel it. I will look as soon as I get back to my truck rehab project in a couple of weeks to see how it is working

[T748]

I mounted a 25 gallon tank in the spare tire area of my 63 longbed. The tank and mounting straps were taken from a mid 70's Chrysler New Yorker. The front strap tabs were welded to the shock crossmember, and the rear just uses carridge bolts through the bed. The fill tube comes out in the area between the bumper and the tailgate. It's behind the rubber flap on the right of the license plate in the bottom pic. -Tom.

[asf93555]

[quote="jarheadsgt"]I did this in the 70s whit an olds tank, a big flat one I got from the county boneyard and strapped to under the bed where the spare tire rack was. I used anout as much banding as I could and it worked well. I never ran out of gas running cross country to my girlfriends house. I had to add an electric boost pump or it would suck the fuel out of the front tank first, and the rear did not have a guage. I had to shut off the boost pump when it started thumping on the rail, you could feel it. I will look as soon as I get back to my truck rehab project in a couple of weeks to see how it is working [/quote]

nice job and thanks for the great pics . . .

[surfnuke9]

Here is a pic of the tank and a frame I made out of 1" square steel tubing and 2" angle iron to support it.

Plan is to hang tank and frame from the frame rails using 1/8" by 3" steel flat bar stock.

Shouldnt go anywhere.

Also, while I was at it, I found a Dodge decal that fits my tailgate very well and put it on.

[MOPAT]

Looking good!
How far below the rails or above the ground will it be?
Where did you decide to put the filler?
I'd like to see the "installed" pictures when you get time.
Pat

[surfnuke9]

The top curvature of the tank fits the rear crossmember almost perfectly, but the tank hangs down too low in my opinion.

I plan to move the crossmember back about 4 inches from its current location. That will allow me to raise the tank another 3-4". Gett at the rivets to move that thing is going to be a PITA. Will likely have to pull the bed boards above the upper ones to get at them.

Figuring out where to put the filler on a Ute is a bit tough. My plan for the filler is to install a flush mount stainless marine style filler in the top of the drivers side rear fender and run the filler pipe/hose from there through/under the inner fender/bed bottom.

That was one of the reasons I picked the Bronco tank. Has a center, drivers side fill connection.

[hampstead38]

How many gallons is the Bronco tank?

[surfnuke9]

33 gallons

[junior]

Look in plastic mart in the internet,they have 12 gallon plastic tanks cheap. Bought one for my 47 dodge 1.5 ton truck back in 2004. Good luck!

[calmauzy]

Here's what I did. Purchased a new 65 Mustang 16 gallon tank on line (came with sending unit), you can also get them in I believe a 22 gallon as well, both will work, the 22 gallon isn't flat on top but there's plenty of room for it. Had a fabricator make a square stock frame to which the fuel tank was bolted to. He drilled four holes through the tank frame into the trucks frame then spot welded the nuts to the frame. Four bolts hold the tank in place against the frame. Purchased a aftermarket fuel door for a Jeep and had him fab it up inside the trucks bed. No more gas smell inside the cab. Works perfectly, even the Mustang's sending unit works with the dash fuel gauge. Doesn't hang down, tank is hardly noticeable from the rear.

[63d100sixer]

calmauzy....thats a slick set-up there..Ive been pondering doing almost the same thing, with the filler door in the bed floor...my only concern is what if Im runnin with a full load...I guess I can always just fill up before i load the bed, but thats too easy...