Gravity Flow Bed Tank Plumbing

[JLandry]

Has anyone successfully installed a DIY gravity flow type aux tank in the bed of their 2013/2014 Ram truck?

If yes, can you please share how you connected it to the fuel filler neck (or possibly a vent line) to fill the main tank?

Thanks in advance,

John L.

 

[jpickens]

Friend of mine put a 75 gal tank in the bed. I believe he T'd it into the vent line that runs back up near the filler neck. He has a valve on it but leaves it open. When he fuels the truck he only puts fuel in the aux tank in the bed. I asked him why - he said NEVER EVERY take the factory fuel cap off if the fuel gauge in the truck reads full.

 

[JLandry]

When he fuels the truck he only puts fuel in the aux tank in the bed.

This is what I do with my current truck... I normally only fill the aux bed tank. The main reason for this is I have a filter / water trap located in-between the bed tank and the main tank to pre-filter the fuel along the way. This keeps the main tank nice and clean.

I asked him why - he said NEVER EVERY take the factory fuel cap off if the fuel gauge in the truck reads full.

Shortly after I installed my aux bed tank I left the valve open and the cap off the main tank because I was using a flashlight to look in the filler neck to see how fast the fuel was trickling in. I'm not sure how I could have been so stupid, but I walked away from the truck, got distracted by something else, and remembered to go back to the truck about 3 hours later. I was horrified to find a large puddle of diesel in my driveway under my truck. What a mess to clean up.

Sure learned my lesson!

Now I have an electric fuel cutoff valve between the bed tank and main tank with a switch in the cab.

John L.

 

[B.G. Smith]

It don't take too much diesel on the ground at todays prices to pay for an electric switched shutoff valve. bg

 

[truckin-on]

Yep. I installed a 42g tank/tool-box combo that works great. I used the kit from RDS: "Diesel Install Kit for Auxiliary Diesel Fuel Tank Fits Ford, GMC and Dodge Trucks, Model# 011025". Basically, you take the filler neck out, cut off about 4", and fit the new aluminum T with check-valve, and you're good to go. This adapter has a check valve to stop the aux tank from overfilling the main tank so that it does not overfill. I found it easy to install, other than being a bit fussy to get the filler neck out and back in.

Available here: http://www.unionhydro.com/RDS_Diesel_Install_Kit_for_Auxiliary_Diesel_Fuel_T_p/rds011025.htm

As I don't leave the aux tank in the bed except for when I'm towing in the summer, I installed a shut-off valve at the tank (included in the above mentioned kit) and a quick-disconnect for the fuel line. I used a small tractor hydraulic coupler that seals both the male and female ends when disconnected. I mounted the tank with some brackets bolted and reinforced through the tool-box part of the tank sides and used large turn-buckles down to the front corner tie-downs in the bed. Very solid mounting and easy to remove in minutes when I want the full bed available.

Originally I had an in-line fuel filter between the tank and the filler neck, but believe it or not, it would NOT flow enough fuel when the aux tank got down to less than half full. I was totally puzzled by this, but there seemed to be enough restriction in the line and filler neck adapter to prevent it from draining the aux tank. I removed the filter somewhere at a campground in OK and the problem was totally solved. I decided the extra filter wasn't needed anyway as what's the difference between filling one tank or the other when it comes down to it.

When parked overnight, I try to remember to flip the aux tank valve to off, but I don't think it's necessary and I've never had a problem with any leaks. Being able to isolate the aux tank also makes it easy to fuel both tanks at once if your at a two-pump diesel station, saving a bit of time as you go for a loan to cover the 70+ gals of diesel you're about to buy

-truckin-on

 

[JLandry]

Yep. I installed a 42g tank/tool-box combo that works great.

Thanks Truck-On!

John L.

 

[jpickens]

I'm getting ready to head down this route. Nabbed a 60g aux tank from a friend... and after a few hrs. of sanding/painting here is where I'm at.

#ad


2014 CTD 3500 w/gooseneck prep package etc.
My plan is to pull the fuel filler neck assembly and weld bungs on the filler neck as well as the vent return line.
I'll hook each up to my aux tank (which will have its own vent).
I'll have a 12v fuel pump and filter combo drawing out of the aux tank siphon tube port connecting to the truck factory fill line (via welded on fitting).
(I'll also have a 90deg ball valve on this line that I can shut off manually if the fuel tries to naturally siphon through the pump?)
Truck vent line will be plumbed to a separate port on the aux tank.
Both of these connections I hope to use a couple pioneer hyd. quick couplers I have left over from another project to ensure a relatively leak free scenario when I disconnect and remove the tank. Is it possible the o-ring seals in these hyd. couplers aren't diesel fuel compatible?

My goal is to be able to refuel myself while traveling down the road... can you guys spot any flaws in my initial design before I get moving on this project?

Thanks
Josh

 

[Brocky]

I also used the RDS auxillary kit from Northern Tool on my 06 F250 with a 35 gal Aux tank. If I leave the included shut off valve open when NOT towing it trips the tank overfill sensor and check engine light mixed into the fuel guage. After filling both I use the Main down to 1/4 then leave the valve open overnight, then shut it off before starting the truck. When towing I wait until I am down to about 1/2 on the main, open the valve, and take off. I am getting about 10.5 MPG grossing 21,000#. The gauge will come up to just about full before it starts back down. Hope all this helps.
Brocky

 

[JR]

Depending on The type of pump and amount of head pressure fuel may trickle past the pump when off. You can try it as is and always add a normally closed 12 volt solenoid valve if the pump doesn't hold the fuel.

 

[jpickens]

^ good idea JR on the normally closed 12v fuel solenoid. I did look at those when first getting into this project... it could just be wired in with the pump.
Josh

 

[mpaulson]

Depending on The type of pump and amount of head pressure fuel may trickle past the pump when off. You can try it as is and always add a normally closed 12 volt solenoid valve if the pump doesn't hold the fuel.

I used a 5 psi check valve with my Holly 140 gph pump and even with that it will gravity feed after I shut the pump off when the guage shows full. The guage will continue to creep up to well above the full mark and stay there for a while while I'm driving, obviously still siphoning while the truck is drawing fuel out for a while. I've since contiplated getting a normally close solidoid valve as well, but the tank has never over filled or leaked anywhere. I have the Geno's rubber plug in the filler neck and did run a vent line from above where I tee'd into the filler vent line up to the top of the aux tank. Again, it seems to stop the gravity feed once full and not leak out anywhere.

 

[Kirwin]

This is how I routed the hoses from my Transfer Flow. Ken Irwin

 

[Brocky]

My manual shut off valve has been holding tight so far.. It is not a problem to get out and open it as on a longer trip I usually have drain off some coffee anyhow by then!!
I also used the gladhand rubbers from tractor trailer air lines a grommets where the fuel lines go thru the body.
brocky

 

[Allnew2Me]

Now I have an electric fuel cutoff valve between the bed tank and main tank with a switch in the cab.

John L.[/QUOTE]


John, just curious what type of valve did you use? Solenoid, motorized gate maybe? Thanks

 

[JR]

I used a 5 psi check valve with my Holly 140 gph pump and even with that it will gravity feed after I shut the pump off when the guage shows full. The guage will continue to creep up to well above the full mark and stay there for a while while I'm driving, obviously still siphoning while the truck is drawing fuel out for a while. I've since contiplated getting a normally close solidoid valve as well, but the tank has never over filled or leaked anywhere. I have the Geno's rubber plug in the filler neck and did run a vent line from above where I tee'd into the filler vent line up to the top of the aux tank. Again, it seems to stop the gravity feed once full and not leak out anywhere.

I wonder if there is enough head pressure to overcome the 5psi check when the tank is full?
Does it leak past even when the auxillary tank is at a lower level?

 

[streetdoc]

Like several others, I used the RDS adapter for the Ram truck, there is one specifically for the Ram starting with 2013. After I installed this on Sunday I only put a little fuel in it to check for leaks, none found, and I was not turning the valve off. On the way home from work this morning I saw that diesel had dropped to 3.61 a gallon so I filled it up, will watch closely for any leak by. I don't plan on shutting off the tank unless I have to.

 

[Brocky]

Street Doc
That is what I tried!! If your check engine light comes on, shut off the manual valve and get it reset and then you will have to follow the procedure in my first post..

 

[streetdoc]

Thanks, I'll keep those instructions in my truck. I also have the plug in the fill neck of the main tank, it will be interesting if that makes a difference.

 

[Too Tall]

It would take over a 16' head to overcome 5 psi. I wouldn't put a check valve if you are depending on the weight of the diesel (gravity) to fill the bottom tank.

5 psi / .052 / 6 lbs/gal = 16'
(.052 is a constant, Diesel weights 6 lb/gal.) The formula for calculating the pressure at the bottom is depth x weight of fluid x .052. = hydrostatic head of the fluid.

 

[JLandry]

John, just curious what type of valve did you use? Solenoid, motorized gate maybe? Thanks

Sorry for the slow get-back.

I used one of THESE... a standard electric fuel tank selector valve.

John L.