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Gas tank vent tube mod

TORX

TORX

NAXJA Forum User
NAXJA Member
Location
NWC
I picked up an unmolested stock tank today, and I'm looking at extending the vent tube to fit a few extra gallons in there.

My question is, the vent tube currently runs at a downward slope. If I raise it, wouldn't that allow gas to become trapped at the lowest point of the vent tube? Kind of like the drain on a sink.

Who's done this mod? Any tips?
 
not sure what year your doing this on, but I tried something like that on my '97.

I reached in with my die grinder with cut-off wheel on it, and removed 3/4" of the plastic breather tube that is angled down as such / in the tank. which raised the lowest point, my thinking was it would allow more fuel before sloshing up and stopping the pump. it worked, I put 75L in a 73L tank the next fill up (thats with about 3L in for a 5km drive to the station too) problem was, fuel seemed to fill the tank too high, to the point it was pouring out the pump seal at the front of the tank. not that fill up, or right after, but within a month of doing that mod I had to be carefull how much fuel I put it, otherwise it would leak like a sieve, until I used enough to get below that point.

food for thought.
 
ERratIC said:
Looking what was done here it looks like it would get fuel trapped in the vent line to me.

http://www.go.jeep-xj.info/HowtoFuelTank.htm
Click to expand...

Exactly what I was thinking. I was just wondering if I was overlooking something (ie: where the fuel in the vent tube will go). Gojeep?

Beakie: The tank is off a 95' (metal). Maybe the 97+ plastic tanks are different with this mod.
 
Well I finally got the new tank swapped in this weekend.

I extended the vent right around 55mm.
P1010004b.jpg


I put around 3 gallons in it when I swapped the new tank in, and then filled up today.
P1010005c.jpg


Exactly what I was hoping for. It's going to be nice not having to fill up every couple days now.

Thanks Chris for the tank!
 
TORX Looks GREAT!!! Well Done!!!

Thank You for the info/photos!

-What size tubing is that vent tube extension you added?
-Is that epoxy + clamp?
-Did you cut off some of the original vent pipe?
-Original vent tube O.D. ?

I'm thinking - The top end of the vent is below the fill nozzle but above the top of the tank, and that the whole vent acts like a upsidedown syphon for air. any air bubbles thru or pushes fuel out the top.

Anyway it works-YEA!!!

Thanks,

orange
 
Last edited:
Beakie-
Mine leaked at the flange of the fuel pump couple of years ago. The O ring seal had oozed out. new one about $6 at dealer- used silicon to grease it and snugged the locking ring down slowly, used a popsicle stick to keep that o ring in grove till fully locked, seemed to be a little larger in dia. than it should be. still good now.

Good Luck,
orange
 
orange said:
TORX Looks GREAT!!! Well Done!!!

Thank You for the info/photos!

-What size tubing is that vent tube extension you added?
-Is that epoxy + clamp?
-Did you cut off some of the original vent pipe?
-Original vent tube O.D. ?

I'm thinking - The top end of the vent is below the fill nozzle but above the top of the tank, and that the whole vent acts like a upsidedown syphon for air. any air bubbles thru or pushes fuel out the top.

Anyway it works-YEA!!!

Thanks,

orange
Click to expand...


The vent tube is 5/8" od.
 
orange said:
Beakie-
Mine leaked at the flange of the fuel pump couple of years ago. The O ring seal had oozed out. new one about $6 at dealer- used silicon to grease it and snugged the locking ring down slowly, used a popsicle stick to keep that o ring in grove till fully locked, seemed to be a little larger in dia. than it should be. still good now.

Good Luck,
orange
Click to expand...

thanks I'll have to look into another new seal. in the mean time the tank will be moved above the frame into the bank end for clearance in the next few months.
So I will certainly be needing to get this fixed, thanks for the heads up.
 
techno 1154

Thank You!

----


hummm.. if the extension tube is rotated toward us it will adjust for different levels... (refering to above photo)

Yep! Gotta do this mod come spring!

orange
 
orange said:
TORX Looks GREAT!!! Well Done!!!

Thank You for the info/photos!

-What size tubing is that vent tube extension you added? 1/2" galvanized electrical conduit, with a 90 bent into it. The ID was a tad smaller than the vent OD, so I cut two slots in the sides to help slip it over.
-Is that epoxy + clamp? A little bit of JB weld to help seal it, and a hose clamp to secure it.
-Did you cut off some of the original vent pipe? I cut off around an inch I believe. I wouldn't do it again though, it was a total PITA.
-Original vent tube O.D. ? As said before 5/8"
Click to expand...

Thanks, it was a lot easier than I anticipated. Read the Gojeep write-up, it explains everything step by step.
 
beakie said:
not sure what year your doing this on, but I tried something like that on my '97.

I reached in with my die grinder with cut-off wheel on it, and removed 3/4" of the plastic breather tube that is angled down as such / in the tank. which raised the lowest point, my thinking was it would allow more fuel before sloshing up and stopping the pump. it worked, I put 75L in a 73L tank the next fill up (thats with about 3L in for a 5km drive to the station too) problem was, fuel seemed to fill the tank too high, to the point it was pouring out the pump seal at the front of the tank. not that fill up, or right after, but within a month of doing that mod I had to be carefull how much fuel I put it, otherwise it would leak like a sieve, until I used enough to get below that point.

food for thought.
Click to expand...

Even stock it goes above that level so you didn't put the seal in correctly or it has hardened. Nothing to do with the mod. I have been running at the higher level shown on my site for 9 years now and never lost a drop from there. You do need to make sure your cap seal is in good order though.
 
-- USE MAXIMUM CARE IF WORKING AROUND FUEL---
----
about installing the fuel pump- The bottom of the fuel pump assembly has a sort of rubber peg extending down,
which fits into a recess in the bottom of the tank. Tilt the assembly around going in till you feel it align and drop in place. If all o.k. the flanges of the pump assembly and the tank match, if not o.k. one side of flanges touch and a gap on the opposite side of flanges. Carefully add silicon greased Oring and slowly lock it down. makeing sure Oring is still in its groove.
 
Survived the mod! went for 27 mm from top of tank (73mm)
Near as I can tell, it worked out to 5 gallon-on the button.

Highly recommend pulling the tank for the mod, (Yes , I didn't!)

This is a one time mod that I can highly recommend.
--------------------------------------------------------------------
Many thanks to GoJeep AND the other fine Jeepers who have worked this out.
--------------------------------------------------------------------
--PLEASE BE EXTRA CAREFUL WORKING WITH FUEL!--


orange
 
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