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Aux fuel tank install

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I've grown used to having an aux tank in my tow vehicle. Once/month I tow a 7400lb 24' enclosed trailer 7-16hrs round trip to distant events. My tow speed isn't all that fast because diesel is a big part of the race budget, but I'm always in a hurry to get to the event on Friday night, and then in a hurry to get home Sunday night. I really like being able to drive all the way w/o having to stop for fuel.

While I waited on my Ram Ecodiesel I schemed on how I would install an aux fuel tank. Since the Ram 1500 is cargo capacity limited and my short bed is pretty darn short, I thought I would try something different. Instead of the big aux fuel tank that I put in my F-250, the same F-250 that sold over the weekend <big smile>, I thought I'd try something smaller and easily removable.

After looking at a number of ideas I decided to try to make a 12gal plastic Marine tank work. That's Marine as in boats, not Marine as in Uncle Sam's Misguided Children (1982-1988, Former SGT Gress Ooh Rah!)

I was also somewhat limited by the height of the bed under the tonneau. I had 18" of height available and the thin tanks that stretch across the width of the bed seem have found 19" as a sweetspot.

Sunday I installed the aux tank into the bed and the aux tank kit into the truck's filler pipe. I wasn't able to complete the install because "easily removable" requires a dry-break connector that hasn't shown up on the porch yet. Since I want my aux tank is intended to be easily removable, the hose needs to be easily disconnectable.
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I got the tank off of Craigslist but you can get them at Walmart.

The aux fuel tank "kit." I got RDS Aux kit 11025 which is for a 1.5" fill line. A buddy pointed out last week that RDS also has a 11408 kit for "2013 and later" which is for a 1.75" fill line. I'm not sure what the best answer is on this. My fuel filler hose adapter fit into the filler hose ok.

The install went fine. The only thing that was not ideal is that the drain port that I drilled into the plastic 12gal tank isn't all that strong. As long as I don't put any mechanical stress on it tho, I think it will be fine. I drilled a hole into the tank just big enough that a 1/2NPT adapter would cut threads into the plastic. Then I slathered the adapter with sealant goobage before threading it in. Had I been better prepared I'd have scared up some kind of really serious epoxy. I tested the port for leaks and it's fine. Down the road, if I keep this 12gal container, I might redo that port with some epoxy. If I don't keep the 12gal removable tank, then it won't matter.
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I spent a fair amount of time imagineering how I was going to do the tank's fastening points. The under-side of the passenger side of the bed is pretty easy to get to but I was determined to put the aux tank on the driver's side of the bed. I wanted to be able to fill the aux tank w/o having to lift up the tonneau and climb into the bed.

The underside of the bed near the filler port is hard to get to. Ultimately I decided that I wasn't going to be able to just put eye-bolts into the bottom of the bed and thread nuts on to them from below. I needed a solution that was self-anchoring that I could do from above.

So I did what I always do when I need to imagineer something. I went to Home Depot.
Below is an eyebolt on a 1/4" shaft and a sheet-rock anchoring device. It's plenty strong. I was able to get to the underside of one eyebolt so I fastened it down with a nut. The other 3 have these anchoring doohickies.
#ad


I have a rubber bed mat so I had to cut holes for the eyebolts and hose. The discoloration on the bed mat is from a rainstorm coming thru. #ad
 
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I've grown used to having an aux tank in my tow vehicle. Once/month I tow a 7400lb 24' enclosed trailer 7-16hrs round trip to distant events. My tow speed isn't all that fast because diesel is a big part of the race budget, but I'm always in a hurry to get to the event on Friday night, and then in a hurry to get home Sunday night. I really like being able to drive all the way w/o having to stop for fuel.

While I waited on my Ram Ecodiesel I schemed on how I would install an aux fuel tank. Since the Ram 1500 is cargo capacity limited and my short bed is pretty darn short, I thought I would try something different. Instead of the big aux fuel tank that I put in my F-250, the same F-250 that sold over the weekend <big smile>, I thought I'd try something smaller and easily removable.

After looking at a number of ideas I decided to try to make a 12gal plastic Marine tank work. That's Marine as in boats, not Marine as in Uncle Sam's Misguided Children (1982-1988, Former SGT Gress Ooh Rah!)

I was also somewhat limited by the height of the bed under the tonneau. I had 18" of height available and the thin tanks that stretch across the width of the bed seem have found 19" as a sweetspot.

12gal is really 14gal. As most diesel types understand, the vent design of diesel tanks makes it hard to get the last several gallons of diesel into the tank. With an aux tank you can fill up the OEM tank, the aux tank and a jerry can and then drive home with your trailer. In the morning you'll find that the aux tank has emptied several gallons into the OEM tank because the foam is gone. Now you can top off the aux tank with the jerry can and head out on your roadtrip jam packed with fuel. Note that this requires that your aux tank be vented. Otherwise the hot sun will do you in one day.

Sunday I installed the aux tank into the bed and the aux tank kit into the truck's filler pipe. I wasn't able to complete the install because "easily removable" requires a dry-break connector that hasn't shown up on the porch yet. Since I want my aux tank is intended to be easily removable, the hose needs to be easily disconnectable.
#ad


I got the tank off of Craigslist but you can get them at Walmart.

The aux fuel tank "kit." I got RDS Aux kit 11025 which is for a 1.5" fill line. A buddy pointed out last week that RDS also has a 11408 kit for "2013 and later" which is for a 1.75" fill line. I'm not sure what the best answer is on this. My fuel filler hose adapter fit into the filler hose ok. It was a little on the loose side, but it sure didn't seem like a 1/4" loose.

The install went fine. The only thing that was not ideal is that the drain port that I drilled into the plastic 12gal tank isn't all that strong. As long as I don't put any mechanical stress on it tho, I think it will be fine. I drilled a hole into the tank just big enough that a 1/2NPT adapter would cut threads into the plastic. Then I slathered the adapter with sealant goobage before threading it in. Had I been better prepared I'd have scared up some kind of really serious epoxy. I tested the port for leaks and it's fine. Down the road, if I keep this 12gal container, I might redo that port with some epoxy. If I don't keep the 12gal removable tank, then it won't matter.
#ad


I spent a fair amount of time imagineering how I was going to do the tank's fastening points. The under-side of the passenger side of the bed is pretty easy to get to but I was determined to put the aux tank on the driver's side of the bed. That would make it far easier to fill up at the gas station. If the aux tank filler port wasn't reachable from the driver's side, then I'd have to climb up into the bed of the truck and drape the hose across. Eventually the draped hose would mar up the paint on the L fender.

The underside of the bed near the filler port is hard to get to. Ultimately I decided that I wasn't going to be able to just put eye-bolts into the bottom of the bed and thread nuts on to them from below. I needed a solution that was self-anchoring that I could do from above.

So I did what I always do when I need to imagineer something. I went to Home Depot.
Below is an eyebolt on a 1/4" shaft and a sheet-rock anchoring device. It's plenty strong. I was able to get to the underside of one eyebolt so I fastened it down with a nut. The other 3 have these anchoring doohickies.
#ad


I have a rubber bed mat so I had to cut holes for the eyebolts and hose. The discoloration on the bed mat is from a rainstorm coming thru. #ad

How about some pix of the install of the T connector into the main fuel line.
 
I did something similar with an old 20 gallon fiberglass fuel tank out of my uncles boat. I had to cut out the old fill and vent nozzles and glassed over the holes so it would fit under my truck box. I bought a 2" DOT approved bulkhead filler neck, lined it up under my truck box and cut a hole through the bottom of my truck box with a hole saw. This allows me to fill from inside my box and keep the fill nozzle locked up if necessary. I also drilled a 3/4" hole at the very bottom side of the tank (driver side) and installed a bulk head fitting. I came out of it with a street elbow, ball valve, and another street 90 with a hose barb coming out of the 90 pointed down through the bed. I ran 1/2 fuel line from there with an inline fuel filter to keep any junk out of the trucks tank and from there into the fill neck. I've got a 1/2" N.C. solenoid valve that I am going to install so I can fill my main tank while driving down the road. At first I had plans on installing a small inline pump but I think the gravity drain works just fine.
 
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Interesting post.
I'm with you 100% on the auxiliary fuel tank, but for a different reason.
My wife and I travel with our 1st gen W-250 and a travel trailer. I bought the truck new, and immediately installed a custom built 40 gal. tank in place of the spare tire , (Which I moved up into the bed).
The big advantage we have found is the ability to be more selective where we buy fuel. Using Gasbuddy we can research fuel prices on our route and look for the best prices without the "Sweat Factor" of running near empty while trying to find a fuel station..
We are currently looking at the possibility of buying a new 1500 Eco-diesel, and I would like to install a similar set-up in that truck-if we do buy one.
Jack Dancoe

Rt. Side.jpg
 
The aux tank has now been in service for 19k miles and works fine. Other than the monthly road trips to distant race tracks, in DD mode, it's nice to be able to fuel up only once/month. I've started amusing myself by doing grocery shopping at Krogers on weekends for "double fuel points." By the end of the month I've earned $1/gal discount which is good for 35gal. Sometimes I bring along a fuel can to make sure that I can take on the full 35gal, but that much diesel for ~$1.69/gal always brings a smile to my face.

Hobbies are usually expensive. Never had a hobby where I actually save a couple bucks. Kinda cool.
 
Regarding the Fill hose adapter size discussed in #1.
Go with the 1-1/2" size. I bought a 1-3/4" from Vulcan Performance and it is too big. I couldn't make it fit no matter how I tried.
Jack Dancoe
 
I've started amusing myself by doing grocery shopping at Krogers on weekends for "double fuel points."

That may not be so amusing when the fuel system gets trashed from the bad fuel. I have never seen as bad of fuel as have gotten at multiple Kroger fuel ports. I avoid them at all costs.
 
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