Questions for Aux fuel tank owners

[Tagalong]

My intsallation (based on what many of you have said and done) is simply to pump the fuel via the filler and vent tubes into the main tank.

Those of you who installed an Aux. combo tool/fuel box can you answer these questions... .

I finally settled on the components I need to do this and would like to know if, first does the location of the change over valve matter? i. e. in-line filter, fuel pump then valve, OR valve, in-line filter, fuel pump. (I'd like to put the valve first from the Aux. tank).

Second, must the in-line filter NEED to be for diesel fuel only? I couldn't find an in-line diesel fuel filter, and all the diesel in-line filters were HUGH!

Third, the tank manufacturer says to use stainless steel fittings between the tank and brass connections. I can't find a 3/8X1/4 stainless bushing!grrrrrr

Fourth, the only way I can think of to connect the vent and fill lines to the main vent and fill lines is to braze a fitting on the OEM metal tubes! Man, this sure is gettin' frustrating!!!!!

Thanks

 

[LarryB]

Sounds like you have already worked out how you are going to do the job but I have some ideas anyway. If you just use a simple Y valve, solenoid or manual, for switching the feed line from main tank to aux tank, your return line will fill your main tank as you drive. When the main tank is full, switch back to the main for supply. No pump, no filter, no mess. Only one part to go bad. This is how I am hooking up my 100gal trailer tank.

 

[rrausch]

Going on the theory that the diesel-rated pump I got was going to push fuel harder and more efficiently than it could pull it, I installed mine:

Aux tank--solenoid valve--12 volt pump--filter--main tank filler line.

If you put the filter first, the only time you can change filters is when the tank is dry. With the valve first, you can change filters as long as the valve is off.



I got a piece of 3/8 brake line, cut a section about 4" long from it, removed my filler pipe and drilled a 3/8" hole in, stuffed the section of 3/8 brake line into it and took it and got it welded in.



The filter base I got from NAPA is # 4309. It is a hefty cast-aluminum base with nice big fittings. It takes a NAPA #3123 filter. The 3123 filter is about 4" in diameter and about 6 inches from top to bottom with a drain-cock on the bottom for draining water. This way almost all of my diesel fuel gets filtered twice!

 

[Gary - K7GLD]

I use the same LARGE diesel filter Robert does - but I place a standard auto inline fiel filter AHEAD of the solenoid valve to keep junk out of it that might keep it from fully closing, allowin fuel to continue siphoning after the system is shut off 0 no problems in well over 100,000 miles. It's no problem in my setup to temporarily disconnect the feed hose at the top of the bed-mounted tank to prevent fuel flow during any servicing if the system.



The problem with the simpler system further above that merely switches tanks while in motion, then allowing bypass fuel to refill the main tank, is that you then don'r have a real idea as to how much fuel you have drained from the accessory tank in the process, and it's WAY too easy to forget, and overflow the main tank - otherwise an easy and simple idea tho'.

 

[LarryB]

Good point Gary. How do you tell how much you have transfered with your system?

 

[Tagalong]

Great idea!

rrausch, I really like your brake line idea.

I think I'll do that for both the vent and fill lines. I had that NAPA in-line fuel filter in my hand but it was so big I decided not to use it. I don't think the small metal in-line NAPA filter I'll be using will be a problem.

I am troubled by the connection from the line to the tank however! You're supposed to use a stainless bushing between the tank and brass. I am torn between simply using the brass bushings or the black iron bushings... got any suggestions?

Thanks for your info, it's helped a great deal!

Tagalong

 

[rrausch]

It is a good question. I used brass, with teflon tape in most places and TFE paste on the bottom fitting.



The people at Aero Tank did not specify, but they were so busy the day I was there they didn't have time to offer me much advice. The Aero is a good tank though. Nice welds and very thought-out engineering & construction.



Maybe a Metallurgist could chime in here and tell us if aluminum against stainless would cause less problems than aluminum against brass.

And if Stainless is a lot better, I bet somebody here knows of a place which sells stainless fittings.



I got the diesel-rated water separator/filter because of the cost of replacement of the injection pump. A little insurance goes a long ways. If I can filter my fuel twice I figure I am twice as safe.

 

[Tagalong]

Got the materials... now to put it into service!

rrausch, thanks for your reply. I managed to find the stainless bushings at New England Hydraulics here in Woburn, MA.

I think I have just about everything I need and will begin to "fit and place" everything before I drill.

Now I have another question... . I had to have a large elbow removed from the bottom of the tank. (It was a gravity feed set up before I got it. ) I also had to weld a patch over the large (1. 5") hole. I had to "wash" out the tank with water before I could get it welded. I just poured in about a gallon of diesel to begin to flush it out. I could see tiny moisture beads on the bottom. I sloshed around another gallon. It's getting better but how should I "treat" the tank before I put fuel in it for use???

FYI I've gone a bit more $$$ in material costs than I've read about here on the TDR. I'm up to about $150. 00. That includes everything; switch, filter, fuel pump, hoses, clamps and fittings.

The filter I'll be using is an in-line filter from NAPA and as I said it's not rated for diesel fuel, but all I really want to do is catch "stuff" from the tank. (Remember, I'm only pumping fuel into my OEM tank. ) So if there is any potential problems with that that I should know about, feel free to pass them along. I've read where several members put a simple screen filter to keep particles out of the switch and fuel pump. Well, here comes the "real rub," inorder for me to remove and prep the bottom elbow hole for welding... you guessed it... I had to (do I dare say) grind the surface area to remove all the weld! I tried desparately to prevent any aluminum particles from getting into the tank, but some did! Now, what are your recommendations for "cleaning" the tank????

Thanks again for all your help.

Tagalong:--)