What is becoming a popular modification to Jeeps; stretching the wheelbase, brings into play all kinds of issues if you stretch too far past a certain point. One thing that junkyard scroungers found out is that Jeep Cherokee (XJ) rear springs, if reversed front to back, add 6 inches to the rear wheelbase of a YJ. It does require a new shackle hanger location, but the biggest issue is it brings the rear axle into contact with the stock gas tank. Many ways have been garage engineered to solve this including putting the stock tank into the bed of the Jeep, adding a fuel cell in the bed area, etc. However the best place for the tank if you need to stay 50 state legal and keep a back seat in your Jeep is to have it under the rig.

I moved my rear axle back 6 inches on project BOYJ and I had considered several options including opening the rear floor and bringing the stock tank halfway into the bed and making a new raised cover compartment for it. However, that made it too difficult to keep the rear seat out of the danger zone for heads-into-the-roll-cage territory.

I decided to build a tank myself and even spent quite a bit of time modeling one up out of poster board until I had a 3-D model of a tank to play with.

It worked out rather well, but in the interest of time I decided to buy an aftermarket tank instead. Sometimes you have to weigh the time VS. money thing and make a decision. I began with a Crawler tank from Gen-Right (also, see our "Visit to Gen-Right" article in this issue). Tony at Gen-Right was not sure if I had moved the axle a bit too far back to work with the standard 18 gallon Crawler tank, especially with the axle swap, so I took one home to check on the fit. As you can see from the pics, I ran into issues. The notch in the skid plate of the tank is centered for the D35 or D44 Jeep axle. The Ford 8.8 Explorer axle is offset to the passenger side just enough to be out of that channel in the skid/tank assembly, so no go. You can see from the pics how I had to lift the tank into place. The skidplate/tank combo is very heavy. This is best done with two persons. You can see how far away I was from mating the skid to the rear crossmember mounting. Close, but no cigar. I believe this would have been OK with a Dana 35 or Dana 44, but keep in mind I moved back a full 6" and the Gen-Right folks spec these for a 5" axle move. I expected to have issues with the bigger tank.

This left me with the option of using the Comp tank. It is a bit smaller at 14 - 15 gallons and it was made for a TJ so I have to mod the skid plate where it attaches to the cross member. I will have to adapt the fuel lines and filler and vent hoses, but that should not be too bad.

Part Two:

OK. To get the fuel pump happening, I picked up a TJ sender/pump unit from a Jeep salvage yard. I had hoped to be able to adapt the stock Ford Mustang pump to the housing of the TJ unit, but when I took them apart, it looked difficult. Now, if I had stayed with a YJ unit, I would have been ahead of the game. I bet you could easily adapt the 'Stang pump to the YJ unit. In fact, if I had to do this over again, I would have had the tank made with a YJ square opening instead of a TJ. However, too late for that. I think you could eliminate the TJ pump and replace it with hose to the filter sock on the bottom of the tank using an inline external pump instead, like the popular E2000. I prefer an in-tank pump...they are quieter and last longer, but they are obviously much more difficult to change on the trail.

I know of guys running the TJ pump with motor swaps like Chevy small blocks and Ford 302s, so I should be good. We will see. One thing the TJ system does not offer is a return line from the fuel rail. I had to add one so I looked at a few hardware stores and came up with two options. One was the barbed fitting shown. I drilled a hole in the top of the pump assembly and with a bit of fuel safe sealant, it should be good to go. The other thing I saw that might work was a steel valve stem (for a truck tire/wheel) with a 90 degree bend in it. If the barb does not work, I will try that. The excess fuel should drain harmlessly back into the tank.

Getting the whole thing back into the Gen Right tank was a bit of a pain. I had to lightly grease the rubber gasket so it would sit into the groove in the inner mouth of the tank and still allow the whole unit to slide into place without pushing the gasket down out of place. I actually had the gasket half installed into the tank and half way on the assembly and then carefully but firmly pressed it into place.

I used 1/4" hose to tie the roll over valves into a 'T' as shown and that will tie into the stock YJ hard line that runs to the engine compartment and, I believe, to the charcoal canister but I have not gotten that far yet. One other issue was that the tank had 1/4" barbs and the line on the YJ is smaller...maybe 1/8", so I have to get that figured out. Another issue with using TJ stuff instead of YJ stuff.

Next, I used the correct size fuel line (rated for fuel injection pressures) and attached one to the return barb I added, but I needed to adapt the regular fuel line to the quick connect TJ barb. I found this fuel injection line repair kit at NAPA. I used a 90 degree one and cut the semi-flexible line to a good length to interface with the fuel injection hose I bought. That will tie into the hard line towards the engine compartment.

Next was the wiring. the TJ wiring uses 4 wires, two for the pump and two for the sender unit. The YJ uses a three wire set up where the pump and the sender seem to share a common ground to chassis (via the metal tank). Remember I have a YJ that came with the smaller metal tank. It seems to be unique in ways compared to the larger plastic tank set up in other YJ models. In any case, I picked up a 4 way set up for a trailer wiring plug and once I get a final wiring arrangement that works, I will update the results.

OK...that left the filler hoses. Earlier I had put the tank in place, hooked up the hoses with the filler neck in the stock location, and tried to see if I had any tire interference issues. To get some idea of flex, I removed the passenger side rear tire and took a High Lift Jack and a Lift Mate and jacked up the drivers side tire as far as I could. I could tell I was on a collision course with the elbow in the hoses, so I needed to relocate the filler neck. Well, coming to a placement that allowed for tailights, the filler neck, and left room for the hinges I will use for the body mount tire carrier was quite a puzzle. I finally came to this arrangement. As you can see from the pics, I ended up about 2" over and up from stock for the filler neck. I used an oval LED S/T/T light to squeeze it all in...no room for a 4" round. The electrical tape in the pic above the tailight opening represents the bottom of the inner wheelwell step. I did not want to cut too high, but I made it as close as possible. Also, to gain a bit more clearance for the hose bend, I cut a pie shaped slice out of the filler hose (not the vent hose) neck and bent it closed and rewelded it. Abit of touch up with a flap wheel and it gave me a precious bit of room I needed.

Now, I still had to cut and extend the vent hose to make it all work. I used 1" EMT electrical conduit that had a slight bend to it. Sharp eyes may notice that the placement of the filler and vent opening on the tank are reversed (it was built with YJ, not TJ hose barbs), an error in manufacturing, but I did not have it changed since it allowed me to not cut the filler hose. I would rather have the splice in the vent hose if I had the choice...I did.

When this is all figured out and I have the Jeep out and flexed up a bit, I will see how my intitial trimming of the fenders did, adjust as necessary, and cover it all up with 3/16" steel door-to-tailgate skins. This will hide all the cutting and moving I did on the tailights and add the support I need for tube flares on the rear.

I learned a lesson in that I would have looked a bit harder at the implications of using TJ stuff rather than YJ stuff with the tank. It seemed like a good way to go, but I think it added a bit of extra issues and cost. It kept me from using the Mustang pump I already had out of the donor car and it made the wiring a hassle of sorts. Still, I think it will work out in the end.