Under Seat and additional Rear gas tank..

I have looked over earlier post about installing a rear mounted gas tank and I am seriously thinking about doing this because I want the extra range the rear tank would provide. I have a few question, first I do want to keep my under the seat tank as an auxiliary tank and the new rear tank would be my main. How big of a tank can be installed in the rear? Would I use the existing fuel pump or have to install a separate pump in the tank along with the sending unit. How does the new fuel line from the rear run into the engine. Does anyone have pictures, instructions and diagrams that they could post? Lastly, on a scale of 1 - 10 what would be the difficulty level for a 60 year old weekend warrior as myself to install a rear mounted tank.

Thanks,

RS Stein

 

Fino's 1970 mini build thread | Page 2 | EarlyCJ5.com

 

Mike Boyink has a good description of installing a '78-on rear tank -

Gas Tank - Installing Rear | SSDutch CJ6 Jeep Blog | Boyink!

The factory Jeep under-floor tank (either '72-75 style or '76-on style) is 15 gal with an additional 11 gal in your under seat tank, so 26 gal total. If you buy an MTS plastic under-floor tank, you have the option of the original 15 gal size or a larger 20 gal size MTS COMPANY, L.C. - Jeep CJ/YJ Gas Tanks model 0050XL. This tank does hang lower than the factory tank, so your rear breakover angle will be affected.

You can also get an additional under-seat tank with the filler on the opposite side, that can replace the factory tool box on the passenger side. So your maximum without Jerry cans could be 11 + 11 + 20 = 42 gal.

Do you have fuel injection? If you have a carburetor, the original pump can pull fuel from either tank. if you have no fuel return line and two tanks, you can use a 3-way mechanical valve mounted in the floor under the driver's legs (this is what I did in my first CJ). With a return line, you will need two 3-way mechanical valves (switch them both) or an electric 6-way valve. The electric 6-way valve will also switch between the tank senders.

http://www.amazon.com/Moeller-Fuel-Three-Way-Valve-Brass/dp/B01607GLVI

http://products.pollakaftermarket.com/Asset/42-159 IS_41-revdd.pdf

Easy project. I'd follow Mike's lead and use the easily-available '78-up tank with skid plate and side-mounted filler.

Buy steel tubing (cheap, safe) and run the fuel lines along the inside of the frame to the switch. From the switch forward, there is only one line, so you can take over the existing plumbing.

 

imho, I would under no circumstances cut the 2 diagonal braces in the rear of the frame. I had to buy a new frame because the po of my 55 cj did that and it did nit end well

 

Well, could be ... but the '70-up Jeeps do not have it, and they do not suffer any obvious problems. I believe those braces are present to reinforce the pintle hook mount - from the military days where Jeeps were regularly used to tow battle equipment.

I (we?) would certainly be interested to hear more detail about your problem.

To the OP, if it bothers you, there is a reinforcing plate that goes on the inside of the cross-member, and a corner gusset. Classic sells the plate along with the rear cross member - maybe they would sell the reinforcement to you by itself. However, the parts book says that these are only supplied with the draw bar. The frame that goes with the rear tank has no obvious change other than deleting the two angle brackets.