Larger Gas Tank On 71 Cj5

So I am hearing that one can use a 72-75 20 gallon gas tank on a 71. I wonder if the 4 vent tubes being the reason they are never listed as fitting the earlier CJ5?

 

a 20 gallon tank is going to be thicker than the stock 15 gallon one ground clearance will suffer.

 

The '72-75 tank is the same volume as the '71. If you have vapor recovery, it should be the exact same tank as a '72. In '73, they changed from the expansion tank under the rear fender to a plastic liquid check valve. I believe the '73-75 tank has two lines, but these lines run inside the tank to each corner, like the four lines of the earlier tank. If you want to use the 2-line tank, you could plug the extra nipples on the expansion tank. These tanks are all a nominal 14 gallons.

There is a 20 gallon plastic oversize tank available from MTS, but it hangs down an extra couple of inches.

 

My 71 does already have a rear mounted gas tank 14 gallons I think. An under the seat gas tank does not seem like a bad idea. Thirty years ago my 66 Dodge truck had 3 gas tanks and one was behind the seat. With the wide block 318 I needed all of them. But it seems easier to put a larger one in the back. Right now my skip plate is at 17 inches above the ground. I figure once I install my new bds lift kit and new shackles it should be near 20 inches. Perhaps I can also raise the tank another inch and half because of the body lift. So then the 5 extra inches on the tank might leave the skip plate at 15 or 16 inches clearance.

 

Most of the work I have done to my CJ5 was in the early 90's before internet. It was much harder to get information. You had to know or know someone that did. From the information I have gathered now with the larger MTS gas tank they provide you with spacers to reuse your old skip plate. If I choose to raise the tank and skid plate I would have to find the appropriate spacers for both. I think finding proper spacers should not be a problem. Just for years I thought the later CJ's had a larger tank dimension wise was the reason they were never listed as a fit also for pre 72 models.

 

The fuel tank capacity on the 71 is 15 gallons, thats the factory rear tank. Don't know where your getting 14 gallons from.

 

Official word from the '72 manual is 16 gallons.


The '71 tank is identical to the '72 tank, if expansion tank is present (It was nation-wide in 1972, pretty sure also in 1971). The '75 manual says it's 15.5 gallons - maybe because of the change in plumbing - no expansion tank, instead a liquid check valve. I pulled 14 gallons from my memory... it's definitely larger than the 11 gallon under-seat tank. but not as large as 20 gallons.

 

I just figured the dents and layers of rust or perhaps never having run out of gas in the tank.