auxiliary fuel tank install

[Paul Holstine]

I just pulled an auxiliary fuel tank out of my parts jeep (74 wagoneer). It was mounted between the frame rails, behind the rear axle (spare tire carrier area) Gonna put it in my 78. The owner of the parts jeep had disabled the tank, but I found two different tank switching valves on the 74 frame rails. According to a co-worker, who is very knowledgeable about the vehicle, this is a factory setup, and operates like this: since there is no separate filler opening in the fender for the aux tank, the aux tank fills by gravity flow after the main tank is full, through a 1-5/8" i.d. hose which runs from the main to the aux. Since the aux filler neck is on high side of the drivers rear side of the tank, I'm having a hard time wrapping my brain around this concept. I'm also curious about whether I could Y the filler hose directly into the aux filler (to avoid punching an additional filler hole in the driver's rear body panel. Anyone have any words of wisdom?. Can't find anything about this in the tech library. pholstin@netscape.net

[ February 15, 2003, 04:29 PM: Message edited by: Paul Holstine ]

[FSJeeper]

I bought a wagoneer just for the new aux Aero 29 gallon tank it had in it. Couldn't go wrong for $100. It was set up exactly as you described.

I am using it as my main tank now and will just have a direct line to it.

I don't see any reason to change the original setup, but you could easily modify it several different ways. If you are using both, I would leave it the way it was installed.

[BostonWagoneer]

Originally posted by Paul Holstine:
I'm also curious about whether I could Y the filler hose directly into the aux filler (to avoid punching an additional filler hole in the driver's rear body panel. I'd like to do this with my setup too. I hope to be installing it in the next few weeks.

[Elliott]

I had a similar setup in my '81 Cherokee. If I recall, it was set up to fill the rear aux tank from the filler hose and then it flooded into the front or main tank. It worked pretty good like that.
It didn't have any switchs, just had lines hooked up that caused it to fill from the rear tank as you drained from the front. Nice like that, but probably only works in a closed loop fuel system.
Then there was an inline pump also, in case the front was empty and you only had $$$$$$ to fill the back tank..... you could pump a gallon forward to start the siphon to suck the rest up front because it won't flood forward until the tank is full. Don't know who made the tank.
Another more common set up had a metal filler neck that had a Y, allowed you to fill either tank from one filler. Probably be worth making one of those.

[ February 17, 2003, 08:06 AM: Message edited by: Elliott ]

[CheapJeep]

mine was et up similar, fill rear, then fills front from one filler. i have it in my project as a main tank, i had teh front feed tube welded up and i just run a feed/return line to it. mine was made by 'trail blazer'
check River Beast's post 'a picture is worth a 1000 words' his parts truck has one similar to mine, but his fills from teh pass side with a stock looking fsj filler.
Scott

[Robber80]

I have two tanks on my jeep, and the PO put a second filler tube on the rear tank. I filled it up when i got the jeep, and have never been able to use the rear tank. So far i think its the valve that switches tanks. Does anyone know where to get a generic valve like that?