Sitting on bombs? (CJ gas tanks)

A gallon of gasoline is equal to 14 sticks of dynamite in explosive force. I guess a full tank of gas (10 gallons) if ignited at one time could have the blast 140 sticks of dynamite. If it blew up with you sitting on top of it, just think you could thumb a ride home with a space shuttle.

Over the past 40 years we have had several jeeps with the under the seat gas tanks. And have never had a real problem.

One of them had some rust on the bottom of the tank. I wire brushed the area clean and noticed some pin holes. I coated the bottom of the tank with some jb weld, and sealed it. So far no leaking gas.

 

Two words "Fuel Cell"

 

Oh, so you don't even have it yet? Well hopefully some of the wisdom imparted here will help give you buying power.

Very interesting thread. Lots of great input. Ok, my 2 cents since you asked :twisted: :

* The chances of explosion of any gas tank is much less than rolling over, so I'd suggest that if you were going to buy a vehicle that was less likely to roll over on a sudden sharp turn, don't buy a Jeep. Since you're going to buy a Jeep anyway, disregard any argument about where the gas tank is relative to you in the EXTREMELY unlikely event of an explosion. Sitting on a 10-gal bomb is equivalent if not less dangerous than a 15-gallon bomb mounted only 2 feet further away.
* Real concerns are that of fumes inside the cabin if it leaks. Do you smoke? If you have an internal leak, you'll get fumes that can ignite with the push of the cigarette lighter or equivalent. But if you have a leak, get it fixed just like any other leak on an externally mounted tank. (but if you're lazy like a bunch of us--me included--, you'll get by with leaving the windows down for now. ).
* Underseat tanks are less volumetric. You'll therefore have to stop at gas stations more frequently, but I guess dual underseat tanks would thwart any probs there. Might be a real concern on long highway trips or extended off-road excursions.
* Underseat tanks are prone to leaking out the cap area (outside the cabin). A full tank + sharp turn to the right = leak out the cap seal. Wish I knew why, but even the newest gas cap won't prevent mild seepage.
* Underseat tanks take up valuable cabin storage space as Boyink mentioned. I like to keep my tools underneath my seat in the '71 (w/ rear-mounted tank). Gotta keep 'em in the back in the '64 (w/ underseat tank) which means no rear seat. That's ok by me b/c I have no passengers. Ever.

Ok that was more like 5 cents' worth. Keep the change. Good luck with whatever you decide. I'd really like to see what dual underseat gas tanks look like. Got pics??
-Alan

 

mcruff, I won't disagree with you . . . as you suggested kaiser probably did have changes in the works but AMC might have sped it up . . . I'll have to go check my photo collection. I once owned a '77 F250 4x4 that had the tank filler mounted on the cab next to the door handle.

I would think that side collisions are generally avoidable (just because the light is green doesn't mean you shouldn't look both ways anyway) while rear end collisions are not. Still 1800 side saddle deaths is a big number here. Yikes!

 

Alan: You saw my "Genuine Jeep" locking gas cap didn't you? It doesn't leak at all around the seal . But, it leaks out the key hole !!! R)

 

Alan, Thanks for your imput. I don't smoke and I did not smell a whift of gasoline the many times I spent checking it out/driving it. Its one clean jeep -- the top of the gas tank looked like you could eat off it. Oddly enough, I didn't pull back the carpet on the pass side to see how that tank looked. The pass seat folds forward to allow access to the rear and between the two front seats there's a valve to switch between tanks and a lever to engage the PTO.

I've already "bought" the jeep, but until the actual exchange of cash and title occurs, I won't claim ownership of one !

 

Sounds and smells good then!! You'll be fine.
Good luck and let us know. Oh, be sure to snap a few pics and post 'em here once that title's in your hands.

 

THE only thing I worry about with the underseat tank is it proximity to my left hand which may have a smoke in it while I'm wheeling. Constantly reminding myself, right hand ..right hand. Thats the only reason I want to put mine in the back.
But as of yet haven't gone to the trouble. Have even considered putting one on the passenger side also, could use the range when I drive it to the hunting lease instead of towing it.

 

Try a jerry can instead of another inside tank, at least this way you would still have the tool box, I couldn't function very well without the tool box under the seat, carry to much in the Jeep to loose that!!

 

This was not factory, someone swapped this into the vehicle, Ford stopped putting tanks in the cab of there Pickups in 1972 the 73 models had it inside the frame rails underneath the bed of the truck.

 

IMO, the short filler neck and unvented cap are more likely to cause trouble than the crash worthiness. I once had my F100 towed away by the fire department because some local deliquents were trying to set it on fire. Same problem the Jeep under-seat tank has - short filler neck, unvented cap. I was parked where the full tank would slowly drip-drip out of the cap.

Also, only gasoline mixed with air is explosive. Liquid gasoline will burn, but if it stays in the tank it won't explode. I'd suggest under-seat tank owners be super-vigilant re leaks.

Aren't some of the vented caps better than others? There's a labyrinth in the cap that's supposed to vent fumes but prevent liquid from exiting.

 

I carry a jerry can, now that I don't like being on the road with that thing full of gas. Even when I'm towing it I usually wait to fill until I'm almost there. Wouln't take much of a bump from someone not paying attention to set it off.
Only reason I'd consider doing away with my toolbox is because on the one I was thinking about doing it on the box is all rusted and I just happen to have a spare tank and valve I could use when and if I ever get around to it. :? Besides I think it might look cool to have one on each side.

 

Boyink and mcruff, I did a bit of flipping in the latest trucktrader magazine (Oregon edition), three 1976 Fords had in-cab tanks, one 1975 Dodge had an in-cab tank and the latest model year chevy with in-cab tanks were the 1972's.

 

link to a 1977 Ford F-250 with an in-cab tank -- click on photo to enlarge!

http://adcache.trucktraderonline.com/4/6/2/75143062.htm

 

I looked real close at this and I have to say this was not factory, it may have been dealer installed or aftermarket use of pre 73 equipment but it was not installed at the factory. The fuel door is in the bed of the truck exactly where it is supposed to be, the spare tank if it was a factory unit would have been on the other side of the bed or if it was a long bed it would be in front of the wheel well on the same side as the factory rear tank in the same location as the factory installed tool boxes that were under the bed with access thru the side. You have to remember that 74-78 were the years that gas was rationed and or hard to get, virtually every picup that was driven then had some kind of auxilery tank in them or on them. My dads Chevy had a second tank that was installed in the frame rail instead of a saddle tank, aftermarket installed, my dads 1977 Ford 1/2 longbed had the second tank mounted in front of the wheel well on the bed, right in front of the original rear bed mounted tank, it was dealer installed. You may find lots of these trucks and if you know the history you'll find out they were installed at the dealership or an aftermarket installation but not from the factory.

 

Could be. I didn't have a crew cab. I do remember my 77 standard cab being almost useless for carrying anything -- you couldn't put nothing behind the seat! I could put more stuff behind my Courier 4x4 (yep, converted to 4WD)'s seat!

 

I have seen several of these over the years that have been converted, actually looked kinda neat!!