Another rear fuel tank question...

Looks like I might have found some salvage options for rear fuel tank set-up. Are there any pros and cons to a 71 rear tank set-up (with filler neck above right rear taillight) as opposed to a 76 and later set up? I think the 71 still uses a vented cap (like an underseat tank) whereas the later model would have a vent tube? Anything else to consider? Both should have fuel return lines I think, and I would either have to put the 71 filler cap where the reverse light is (and move the light up), or hopefully slight modification to filler nect and put the filler cap above the reverse light. In the long run, I'd like to set-up a switch to use both tanks if needed, but initially would probably just run the rear. For hard to describe reasons, I like the 71 as that would be 'more correct'...whatever that really means. My Jan 70 production date is almost at the end of the underseat tank set-up so the 71 set-up is pretty close. But in reality I need to use whatever would be the best solution in terms of functionality.

thanks

 

If you find a good hose supply shop you can get rubber hose rated to carry fuel. That's what I bought last time I did this install on the CJ6.

+5 gallons, some weight on the rear for a better ride, and some additional interior storage for tools and parts = big win for the rear tank for me.

 

Yup - that's exactly what I am looking for - really could use some weight on the rear axle (and some lockers) so this should help. Haven't decided completely whether I would keep the underseat tank for spare or use the space for storage. Sometimes its a long way between fuel stops in the western CO and moab areas. Either way it will be good and as well as reduce the fuel smell in the cab - although that has been a lot better with the new sending unit and o-ring.

Thanks all for the info - I will need to make sure I can get all the bracketry and filler neck etc if I go the 71 route. I originally called the salvage as they had a complete set-up from a 78 as I was intending to go that route, but when he said he had a 71 I thought that might be interesting.

 

Well I got my hands on a complete rear tank set-up - its from a 71 so it has the separate mounting system/brackets for the tank and skid...but I got all the brackets and such.



Some questions though...

1) What is the best way to plug the 2 vent lines that would have gone to the charcoal canister?

2) I like having a vapor return from pump which the salvaged sending unit does not have. In the long term will probably just replace the unit with a vapor return unit, but wondering if I could use one of the charcoal vents that would otherwise be plugged as a vapor return.

3) So the filler neck is quite interesting...looks like the tank vent hose connects into the large filler neck hose. I disconnected the vent hose from the neck at the nipple, but Before I start tearing it apart anymore, wondering how the nipple is mounted into the filler hose? The large filler house has a puncture in it down near the tank connection...trying to figure out how to replace without damaging the metal portion of the neck etc.



4) Finally, aesthetics...where to mount the filler neck? The late 71 had it on the right rear above the taillight, but that would be exactly where my reverse light is. Put the filler in place of the reverse light? Move the reverse light up to the 71 location. Custom fit filler hoses (assuming I can replace the originals on the neck) and put the filler on the right quarter panel about where the spare tire mount would have been?

many thanks for the feedback

 

Thanks Tim - got the vent line nipple apart from the filler hose. Not as complicated as I thought at first. The rubber filler hose was so hard that I thought there was a metal sleeve on the inside that I did not want to damage. Once I got the locked gas cap off I could see in a lot better and take it apart. I can recreate that set-up without too much hassle with new hose. I do think its a replacement tank as well - if for no other reason than its in too good a shape inside and out - but I don't know all the slight differences in features year to year others probably do.

Need to test the sending unit resistance - if its good then I will look into adding a nipple for vapor return. If not then new sending unit - I do want the fuel gauge to work.

When you say 'loop back' - loop each vent back into itself or connect one vent directly to the other?

thanks - its gonna be a while before I get this installed but getting all the pieces is a big start.

 

Thanks - just wanted to make sure.

 

This filler neck is a little smaller than my underseat tank filler neck - surprised it wasn't the same - but its not as small as a late 76 and after neck (at least from what I remember). Not really an issue either way. I am hesitant to mount the filler neck/cap in what would be the natural location that tim shows as my reverse light is right there. I don't really want to move the light - not sure why but it is what it is...maybe because it would bother me that the left side light would be lower. Could just go without the light I guess. I think I would most prefer to mount it above the reverse light (about where tim's light is), but would have to find a hose to work and there is not a lot of room up there.