Write up: Gas Tank Relocation

[Old77]

At the request of some fellow GMSBers I am creating this thread to show how to relocate your side gas tank(s) to the rear of your truck. I did this project back in 2004ish so it’s been a few years and I didn’t take as many pics as I would have if I’d known to make a build thread for it so bear with me! Hopefully I don’t leave out any crucial details. The point of this project was to move the gas tank from the side position out to the rear of the truck. I used a tank that was meant to be for a blazer or Suburban but there may be other tanks that’d work just as well or even better. This mod was necessary in order to fit my seats (from 2002 Silverado) in which can be found in my other thread in the interior section (http://www.gmsquarebody.com/forum/showthread.php?t=375)

NOTE: You’ll want to wear eye protection because you’ll most likely end up dropping rust all over the place as you do this conversion. I did this conversion early on in my truck build so you’ll see quite a bit of rust that hadn’t been taken care of yet but is no longer there now that the truck is “complete” if there ever is such a thing

 

[Old77]

Pictured here is the original tank on the passenger side. Mine came with just one tank but many have a tank on both sides of the truck.

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This tank is simply held on by two straps and the filler neck is connected at the bed. The screws for the filler neck are accessed at the filler neck hole. Remove those screws and there should be 3 holding the filler neck up. Once those are out then take down the straps that are holding up the gas tank. They are held on by a bolt on each side of the strap on each side of the tank. Remove one side at a time and lower the tank. With the tank lowered you can now remove the second bolt for each strap. Sorry but I don’t have any pics of the tank after the drop.

 

[Old77]

From there, you want to get more hard line to extend the gas lines from that side location to the rear of the truck. You should be able to pick some up at the hardware store and you’ll need to bend it yourself once you get to the rear. We only needed to make two bends in the line, though. The line should just go straight back, turn towards the middle and then turn downwards as it gets to the tank. We used a small hand held tube bender and it seemed to work great!

Pictured below is the future home of the tank (as stated this was prior to restoring the frame or putting my current bed on so disregard all that nasty rust! )

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What is not pictured there is the original brace that went across the top originally used to support a spare tire. We used that to hold one side of the support straps for the new tank and then angle iron for the side at the very rear of the bed. This can be fabbed any number of ways but this was the easiest and most straight forward for us.

Pictured here is the area all ready for the tank to be installed. (The right hand side is the side of the rear axle, left hand side is the back of the bed)

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You’ll see the wiring hanging down for the sending unit, the black anti-squeak stuff that we applied to the metal and the gas tank (pictured later on), the gas line peaking through and you see that we had to cut off the exhaust tips to make room. These were reconfigured after the tank was up but they were too close originally. If you look real close to the right hand side of the pic you’ll see two (2) holes drilled into that cross beam where the straps will end up being fastened to in order to hold the tank up. On the far left of the pic you’ll notice where we fabbed up the attachment for the straps towards the rear most portion of the bed. The straps have threaded ends so they are held on by nuts and we used a ratcheting box end wrench along with some deep sockets to attach them. That set up at the rear most part of the truck was all created from angle iron and cut to shape and size. The most difficult part of this is working around the rear bumper brackets. It’s not the easiest thing in the world but is probably the most difficult part of the whole process.

 

[Old77]

Pictured here is the tank prior to install with the anti-squeak already applied.

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The install is pretty much a two person job. One person to hold the tank up and fasten the straps on the side nearest to the rear axle and the other person to fasten the straps near the bumper. We found it easiest to fasten the straps near the rear axle first to work better and then the other side gets bolted up while the person already underneath holds the tank up. This can also be accomplished with a jack and a piece of plywood but balancing the tank like that can be difficult.

Here is a pic of the straps fastened to the brace nearest to the rear axle

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I will eventually run the filler neck to behind the taillight but this is how it sits for the time being.

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[Old77]

Next up is a series of pics for the filler neck. Sorry but I did not take enough pics to do this justice. I should have taken more pics at the time but hopefully these will give you an idea. The hard part of this configuration is getting the filler neck hose angled enough down so that the gas gets into the tank without backing up into the neck. It probably took us 5 or 6 different attempts to get this right and the bed braces along with the frame made this a fairly difficult task. We took a 90’s GM filler neck (I think from an Astro van ) and cut off the pipe that we didn’t need and fit in some filler neck hose that is rated for gasoline transfer. In the pics where the filler neck is attached in the bed is not the finished product but still looks similar to that (but with a different bed now). We just haven’t had a chance to really finish it off to my liking yet.

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Here’s a shot of the filler neck coming out of the bed. Like I said, not finished off at all but at least functional at this point. Getting this truly finished off is on the list of projects in the future

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If I was to do this over again (and I may in the future) I’d look into getting the a tank that I could fill by flipping down the license plate like the 70’s Impalas and may others from the past. I think that’d be the cleanest way to do this gas tank relocation but this way works too. In the end, the filler neck will be flush with the bed floor and look really nice. We also cut an access panel in the floor of the truck in case the sending unit ever needs to be worked on so that we don’t have to drop the tank. This is not a necessary step but we found it handy and have a door over this access panel to that it looks more complete. Once we have the bed liner sprayed you won’t even know it’s there.

 

[Jaymez]

Nice write up.

My only thought is I can see having something IN the bed that might block the fuel filler. If you don't relocate to a bumper filler, I'd consider moving the filler to behind the tail lamp and use small cabinet hinges to allow the light to swing out.

 

[Old77]

Yeah, behind the tail lamp would be a cool mod as well. We'd tossed that around too but didn't execute it at the time. It was a matter of getting that filler hose to the tank without any low spots. I'm sure it's possible, though, and would definitely be slick.

 

[crazy4offroad]

Yes very nice writeup. When I was planning this, I had actually thought of using my 4" angle grinder with a cutoff wheel to cut the bedside in a square around the gas door, then cut a new hole for it at the back of the bed behind one of the rear wheels. Weld the door in its new location, then weld the patch I cut out back in the hole where the door came from. Finish it out with some body putty and it would be done!

 

[Old77]

Yes very nice writeup. When I was planning this, I had actually thought of using my 4" angle grinder with a cutoff wheel to cut the bedside in a square around the gas door, then cut a new hole for it at the back of the bed behind one of the rear wheels. Weld the door in its new location, then weld the patch I cut out back in the hole where the door came from. Finish it out with some body putty and it would be done!

We'd thought of this too but we found that the angle that the filler hose would have to take in order to get to the gas tank was too sharp and make filling extremely difficult if not impossible. There's not a whole lot of room between that inner wall and outer metal of the bed and with the blazer/burb tank you have to bring that filler hose in above the frame rails.

 

[Swims350]

ohh the blazer tank mod. I thought you were gonna throw the saddle tank in the back lol.

I like it, just don't like the filler in the bed.

 

[Old77]

ohh the blazer tank mod. I thought you were gonna throw the saddle tank in the back lol.

I like it, just don't like the filler in the bed.

I'm with ya. Once it's finished off it'll be pretty slick and flush with the floor and that'll be posted up

 

[Swims350]

My old man wants to do a blazer tank, or I should say bigger tank period, but he wants a rear mount and I told him most of the time it's in the bed floor he hates that idea period. He wants it behind the licsense plate, I kept trying to tell him I think that would be lower then the tank itself. Our buddy has a 4x4 stepside done that way, but it's a car tank mounted in between the rails over the rear end. So he wants his filler in that same place, I tried to talk him into a taillight filler. I like that idea alot.

 

[Old77]

I do too. I think a taillight filler would be really slick and very doable. There'd be some hurdle with the taillight wiring, getting the hinges mounted so that they are not visible on the outside and stuff like that but I think it's very doable and would look great! I think that mod would work well with blazer tank in the rear frame rails.

I didn't like the idea of a fuel cell being inside the bed because to me, unless you've got a drag truck, it just looks way out of place.

 

[RetroC10Sport]

If I were going to do it, I'd run just a long ass tube to the original filler location...I hate doing body work...

 

[Old77]

If I were going to do it, I'd run just a long ass tube to the original filler location...I hate doing body work...

There's all kinds of obstacles between the rear of the truck to the original filler location to make that idea near impossible