RDS 51 Gallon Tank/Toolbox Installed!

[LightmanE300]

Hey guys, just wanted to post about the latest toy I installed. Northern Tool sells RDS tanks as well, but I got it directly from the factory in Perry, FL. The toolbox area on the top is pretty substantial, and you get an extra 51 gallons of fuel capacity while only taking up 20" of bed length. I got the black powdercoated model. I plumbed the aux tank via gravity feed method right into my main tank. Basically there is a drain on the bottom/side of the tank where I installed an on/off ball valve and a 90 degree hose fitting. Then just I just had to drill a hole in the bed for the hose to go through, and the plumbing is simple. All that's required is to 'T' into the fuel overflow/return line (the thinner 3/4" ID hose that runs alongside the larger fuel filler neck hose) and you're done. There is a vent on the top of the aux tank to allow air to replace the fuel as it fills. The truck's fuel gauge reads full until the aux tank is totally empty and then you know that you're on your regular tank.



I hope that run through of my install wasn't too insane, and folks could make some sense of it! There are pictures of the box in my Reader's Rigs gallery, just click under my name on the left.



Since I know people will ask, the entire project including shipping, tank, and installation parts, cost me around $550.

 

[John - K5AWO]

Nice job lightman. I did the same thing back in '74 to a Suburban. I had a custom 58 gallon tank built for it with floor tabs to secure it to the floor.



Worked just as you described.

 

[FreeBMW]

This the one you got?????







Link

 

[LightmanE300]

Thanks John. That sounds pretty cool about the suburban, but was the tank inside the cabin behind the back seats? I just wonder how it vented without stinking up the 'burb?



FreeBMW - yes that is the tank - however northerntool hasn't updated their site, or still has containers of the older style tank. RDS no longer makes the 41 gal size, it's now a 51 gal size, and only . 5" deeper in length. I also got the black powdercoated model. Unfortunately I dont think RDS has updated their online catalog to reflect the changes yet. You can see their site at

www.rdsaluminum.com

 

[John - K5AWO]

Originally posted by LightmanE300

Thanks John. That sounds pretty cool about the suburban, but was the tank inside the cabin behind the back seats? I just wonder how it vented without stinking up the 'burb?

It was mounted between the rear wheel wells and the tailgate. Height was dictated by the tailgate release handle inside the tailgate. On that model you had to roll the glass down, reach inside for the latch. This also locked in the capacity. Fuel pumps indicated it would hold a few ounces over 58 gallons.



I had a 1/4" pipe collar welded into the left rear corner. Ran fuel line from there to an Imperial gas valve mounted on the side hump of the driver's seat where your hand would just drop down on it. Inside tank 'ON' pumped fuel from the tank to the fuel pump. Overflow fuel not used by the carb went to the factory tank. In the course of an hour, maybe less, an empty factory tank will fill back up from the overflow.



The vent was easy too. I had a pipe collar welded into the top right rear of the tank to accept a standard 55 gallon drum bung hole plug. The rubber gasket prevented any fumes getting into the cab. I drilled an 1/8 inch hole in the side of that collar just below the plug threads. The welder placed a 1/8" pipe collar over that hole. Ran some tubing from the hole down thru the floor of the truck. Sealed the floor opening with pliable a/c duct sealant. Worked like a charm. Used it for 17 years, sold the truck, kept the tank. Still have it.



Safety Issue: This tank was in the cab. Rear collisions are not very forgiving. The tank was made out of 1/8" thick (0. 125 inch) plate. I had the welder install 3 baffles top to bottom, front to back. Each baffle had a 45 degree cut across the corners that measured about 1/2 inch to a side. This allowed for fuel flow, but severely dampened side to side slosh. The tabs that held it to the floor were made out of 1/4 inch high strength steel. I used grade 8 bolts to go thru the floor to some more thick steel plates.



I also installed a SW fuel sender with matching guage. Installed the guage in the ash tray as I don't smoke and that looked like a good place to me for guages.



The thing is heavy, never weighed it, but must be close to 200 pounds. Add 58 times 6 lbs for fuel, and it added about 650 lbs to the rear end for ballast in the winter snows of Utah and Colorado. Never stuck the truck once, those carbide tipped tire chains are awesome with lots of weight over the axles.



The welding was all wire weld w/argon gas by a pipeline welder. Smoothest welding I ever saw. Not a dingle anywhere.



I would do it again in a heartbeat. Especially with high priced fuel now. 20 cents saved works better in my pocket than theirs.

 

[LightmanE300]

Sounds like a cool setup John. The RDS tank is also baffled to help with the sloshing.



One cool thing about having a tank setup with a valve is, I can fill the aux tank fully with b100 biodiesel, and then open the valve to blend in the appropriate amount of my choosing Nice to be able to fill up the main tank 90% of the way and then let the last 10% fill up with biodiesel from the main tank.

 

[TexasDodgeRam]

LightmanE300 did you completly bypass the original fill-hose or can you fill either tank? Also when running on the main tank does the fuel from the top tank drain down as you burn fuel?

 

[RHenderson]

Powdercoat Tank

If I request the on on the above link will it be powder-coat and 51 gal. or did they offer you a aluminum version. Question on the gravity feed, will this have any potential for overflowing you think. and last question can you post a picture of the valve. thanks for any reply as I have been contemplating this very thing but everyones said it would flow out on the ground.

 

[LightmanE300]

TexasDodgeRam - I thought I covered that but let me be more clear. The original fuel filler neck is untouched. There is a thinner line right next to it, which you will see if you look up from underneath. Thats the return/overflow line. I simply cut it, and installed a T. You do not have the option with my setup to run strictly from the aux tank. If you choose to leave the valve open, gravity will fill up the main tank until the aux tank is empty, at which point your fuel gauge will start to move. This is a very very simple setup.



Rhenderson, as I posted above, either Northern Tool has overstock of the standard 41 gals, or haven't updated their site. In any case, unless you request black powdercoat and pay extra for that service, you will get regular diamondplate. I don't believe you can get black from NorthernTool - you should contact RDS directly. Talk to Lamar. The number is on the link to their website that I posted above.



RH - the factory tanks are sealed/dont have a vented cap. Thats why you can fill it up all the way to the filler neck and have no leaking problems. I left the valve open all day yesterday, and after several trips under the truck on the creeper with a flashlight, have determined I have no leaks. It's my personal preference to leave the valve closed once the tank is full, and then open it up when I need to refill. The reason being, there is a vent on the aux tank, and the vent needs to be open when the valve is, just like pouring gas out of a can with the vent popped open. Me being anal about fuel quality, I just don't like having that vent open to the atmosphere sucking dirt and moisture in any longer than it has to be.



RH - the valve is a standard plumbing ball valve, available at any plumbing or hardware store. All it consists of is a threaded fitting that screws into the tank and it has a lever to open or close the flow. Very simple, a few bucks, and just threads right in. Sorry I dont have a pic of the valve but it's totally simple.



My plumbing setup required:

1 - threaded on/off valve

1 - threaded 90 degree fitting coming off the valve, with the lower portion of the 90 having a 3/8" hose barb on it.

1- 3/4ID x 3/4ID x 3/8"hose barbed T. The overflow tube is 3/4ID tubing, but I used 3/8 to go into the T because its a smaller hose/hole to drill in the bed, and there is no need for as much flow as a 3/4ID provides.

4 - hose clamps



After an awful attempt at cutting the hole in my bed(it's not the prettiest), someone pointed out that there's a little rubber cap that pops out in the front vertical section of the bed. Of course I notice this after drilling a huge hole. Those that wish to be less invasive can just go thru that, then use maybe another 90 degree fitting to make the turn.



Good luck guys, hope this helps!

 

[John - K5AWO]

... ... ..... After an awful attempt at cutting the hole in my bed(it's not the prettiest), ... ... ... ... ... ... .



Now that your 'new' hole is history... . Greenlee Tools makes a wonderful hole punch. Can be purchased from any electrical supply house. I am fortunate enuf to have the hydraulic ram punch set. Makes very short work of new holes in steel. Nice clean edge too. Rubber grommets make the edges friendly.

 

[rweis]

Holes in the bed,



I have an air compressor in my bed for the air operated ebrake. There are a couple of holes in the stake frameing that you can run AN-6 through as well. I know they are not at the bottom, but if you pump the fuel from aux to main they could be used.



Isn't there a air vent in the main tank? Maybe it has a roll over check valve that would keep the main from spilling over when the gravity feed aux still has 20 gallons in it and the main is full.



Also assumes the main tank filler cap screws on tight enough to privent spillage through that possibility.



Just some thoughts,



Bob Weis

 

[LightmanE300]

The main tank is sealed in some manner - not sure, however when its full to the brim and the aux tank valve is open, there are no leaks... . and thats all ya need IMO.



I had a hole punch but the shank was too big for my wimpy little drill. I do not have a big collection of tools or equipment, I seem to buy them as I go along. I dont have much use for lots of tools. Oh well, i dont really care how nasty the hole(wouldn't it have to be round to be called a hole? LOL!) is, since its not really visible unless you look for it, and the hose doesn't touch/rub which is all that matters to me. Yes a perfectly sized and placed hole with a grommet would be clean and ideal, however I had to switch valves and adapters halfway thru, and had to 'enlarge' the hole in one direction. It's a friggin mess but ya know what I dont give a darn, as long as the aux tank works right, and the hose doesn't rub. I used a little paint and then clear siliconed all the way around the hole to prevent any corrosion.

 

[FreeBMW]

Is the highest point in the aux tank (not including toolbox space) higher than the OEM fuel filler???

 

[LightmanE300]

Yes FreeBMW, hence 'gravity feed' .

 

[FreeBMW]

I get that part (duh)





What I am worried about... ... . say both tanks are full & you have the aux valve open & you open the OEM fuel filler cap... ... since the aux tank is higher than the OEM filler isnt fuel going to come rushing out????

 

[John - K5AWO]

Originally posted by FreeBMW

What I am worried about... ... . say both tanks are full & you have the aux valve open & you open the OEM fuel filler cap... ... since the aux tank is higher than the OEM filler isnt fuel going to come rushing out????

In that scenario, yes, you will be experiencing an outward egress of aromatic solvents..... otherwise known as diesel fuel.



The volume would be quite small though as the fuel line from his bed tank is 3/8" hose (hence restricted flow).



I would think that if one were to remember the fact that they own a bed tank, they would not be opening the main tank until "after" they had verified that gravity feed valve is closed.



But, if like me, they are experiencing CRS disease... . ah well. Caveat emptor.

 

[FreeBMW]

I always forget my fuel additive at home... . So I end up pouring it in at home... ... . So I would get a bath or I need to remember to shut the valve off

 

[LightmanE300]

Now that is funny stuff BMW. I think as John says, anyone who has an aux tank setup with gravity feed would certainly not open the main cap. With that said, I leave my valve and vent closed, and will probably only open them when my tank starts getting low. Hop out, flip the valve etc, and drive away. . close it when i get home that night or if I stop after the tank is full. I figure that way 1. there will be much less dirt/moisture exposure through the open vent, and 2. there will be no fuel or gravity/pressure in the hoses/connections between the two tanks - for less stress or chance of developing leaks. Sounds kinda silly but if there is no fuel there there's nothing to leak =]

 

[thepipe1]

Why Not Diamondplate?

Lightman:

I had been thinking about increased fuel capacity but thought these toolbox combos were a lot more money. Thanks for "enlightening" me (sorry). Why did you choose powdercoated steel over diamondplate aluminum?

 

[TexasDodgeRam]

He did get powercoated Diamondplate. Look at his Reader's Rig.