MJ fuel tank swap...

[IdahoEagle]

I have an 87 shortbed MJ. I need to replace the tank because it started leaking last week. It's the 18 gallon, that is the only size the shortbed came with. The longbed had an optional 23.5 gallon tank. Has anyone with a shortbed MJ put the 23.5 gallon longbed tank into their truck? If so, do you have a list of necessary mods/parts needed? My truck is a DD and I live in middle of nowhere, smalltown, BFE Wyoming... So resources are very minimal around here... And no, I'm not going to install a tank from an XJ in the floor of the bed or try and cobble something else to use in it... I'm a bit of a perfectionist and would rather do it right than half-assed... And I also use the whole bed on a regular basis...

 

[87manche]

It's not likely going to fit. The 23 gallon tank in my MJ went up past the wheel arch in the frame rail. The filler neck is located differently and I think it's going to run into the mounts up in the front of the bed.

 

[tim500]

Whats the difference in wheelbase between the two? The other way is to cut the section of the bed out between the cab and the wheel well. you could prolly get the tank in sideways, then its not under car. so how important is bed space? if you find the right tool box it will fit over top of it.

 

[kastein]

I have an 87 shortbed MJ. I need to replace the tank because it started leaking last week. It's the 18 gallon, that is the only size the shortbed came with. The longbed had an optional 23.5 gallon tank. Has anyone with a shortbed MJ put the 23.5 gallon longbed tank into their truck? If so, do you have a list of necessary mods/parts needed? My truck is a DD and I live in middle of nowhere, smalltown, BFE Wyoming... So resources are very minimal around here... And no, I'm not going to install a tank from an XJ in the floor of the bed or try and cobble something else to use in it... I'm a bit of a perfectionist and would rather do it right than half-assed... And I also use the whole bed on a regular basis...

If your fuel pump assembly is not rusted out like mine was, just buy a new tank for a shortbed. They are quite reasonably priced and good quality on RockAuto, I got a Spectra one. Coat it with something before installing it and it will last forever.

 

[87manche]

Whats the difference in wheelbase between the two? The other way is to cut the section of the bed out between the cab and the wheel well. you could prolly get the tank in sideways, then its not under car. so how important is bed space? if you find the right tool box it will fit over top of it.

shortbed=113"
Longbed=120"

If you're going to put it in the bed, get a fuel cell and do it proper, rather than relocatiing a stock tank. I can tell you what parts/pump you need for a fuel cell install. Mine has an RCI cell in the bed, just behind the cab.

Really though, I would just find a new shortbed fuel tank and be done with it. Coat it as mentioned above and not worry about it. I highly recommend a skid plate, you'll find the stock mounting points on the frame rail. Otherwise you'll tear it out and leave it ten feet behind you on the trail like I did.