Leaking gas tank fittings

[Fresbone]

I have an aftermarket poly gas tank under the bed of my CJ5. In order to calibrate my Speedhut fuel gauge, I filled the tank to the max and topped it off a few times to make sure it was full. I don’t generally do that - it was just to make sure the float was definitely all the way to the top.

After filling the tank, gas started leaking from some brass fittings that MTS installed to cap off the holes where (I think) emissions lines would have gone. My thought is to use a thread sealant as opposed to simply tightening up the fittings. From what I have read, an anaerobic thread sealant won’t work because it is not metal to metal contact. Any recommendations? I read about a product called Gasoila that seems like it should work.

 

[PeteL]

Permatex #2 has always been my go-to.

 

[timgr]

I'm going to offer a radical solution.
A plastic gas tank will be HDPE (high density polyethylene).
It's very chemically resistant, and adhesives will not stick to it.
You can, however, weld it.
I have a post here about repairing the HDPE tank in my J20 https://www.fsjnetwork.com/forum/viewtopic.php?t=23694
Cut up a Homer bucket and weld the holes shut.

Or call MTS and ask for help.

 

[Jw60]

Heat the brass fitting and work it out then in again.

 

[dnb71R2]

Cut up a Homer bucket and weld the holes shut.

I'll never look at a Home Depot bucket again without thinking HOMER!

 

[timgr]

That's what the HD folks call them...
They used to have a cartoon character "Homer" on the side; maybe some still do.

 

[timgr]

Heat the brass fitting and work it out then in again.

Simple - good to try first before my radical solution.

 

[PeteL]

Cut up a Homer bucket and weld the holes shut.

Zip ties are what I plastic-weld with.

 

[Fresbone]

Heat the brass fitting and work it out then in again.

I don't understand? Heat it to loosen it or heat it to make the plastic conform to it?

 

[Jw60]

I don't understand? Heat it to loosen it or heat it to make the plastic conform to it?

Your heating so the plastic conforms. Plastic likes to strip threads so you can heat n twist gently but heat and loosen it first so you don't just pull threads out.

I have patched a camper freshwater tank with a hole saw and a kitchen carving board. By friction welding the plug onto the tank then the arbor hole was filled with a brass fitting.

 

[timgr]

I think you can try either.
You need to assess whether the fitting can seat deeper into the plastic.
I expect the fitting will come out without any heating.
Then, as you heat the fitting it should seat deeper and seal better in the plastic.
Or, you could remove the fitting, heat the plastic to make it fall in on the hole, and reseat the metal fitting.
If none of this works, you could seal the hole by adding material like I show in my link.

 

[nickmil]

Or call MTS and ask for help.

This first.

 

[Fresbone]

I spoke with MTS today and they recommended putting hose clamps around each fitting. The manager said that is what they usually do regardless of whether there is a leak.

By the way, MTS customer support is great in case anyone out there is trying to figure out where to get a fuel tank or parts.

 

[Fresbone]

Went home and remembered the fittings are female in holes that are flush with the gas tank. No place to use a hose clamp.

 

[fr8dog61]

Ugh!