240z gas tank fuel feed line question

[Dcreech0]

Hello fellow z owners. I hope I can get some insight to a question I have. I pulled my 240z gas tank to inspect the internals and clean it a little. When I pulled the rubber hose off the fuel feed line, I noticed some movement in the metal feed line on the tank. Is this normal and supposed to slightly swivel? The return line does not move in the same manner. 

Edited July 24, 2021 by Dcreech0

[Pop's Z]

No, they are not supposed to move. I did not want to use heat to fix mine as I didn't want to drop the tank, fill it with dry ice and solder it in place, so I used JB Weld. It's held up for the last 10 years. The proper fix is the one I didn't do...

Cheers, Mike

[Dcreech0]

2 minutes ago, Pop's Z said:

No, they are not supposed to move. I did not want to use heat to fix mine as I didn't want to drop the tank, fill it with dry ice and solder it in place, so I used JB Weld. It's held up for the last 10 years. The proper fix is the one I didn't do...

Cheers, Mike

So you had this exact same issue? I wonder if this could be the source of the fuel delivery problem I have been experiencing 

[grannyknot]

Swivel is not good, do you have any leaks around where the feed line enters the tank? Both the feed and return lines are crimped on then lead soldered, I've repaired one with plumbers solder.  The question is did that feed line start turning because the crimp and solder failed or did it rust through?  You'll find out when you drop the tank and have a look inside.

[Dcreech0]

46 minutes ago, grannyknot said:

Swivel is not good, do you have any leaks around where the feed line enters the tank? Both the feed and return lines are crimped on then lead soldered, I've repaired one with plumbers solder.  The question is did that feed line start turning because the crimp and solder failed or did it rust through?  You'll find out when you drop the tank and have a look inside.

I have the tank out. When I wiggle the feed line on the outside of the tank, looking through the fuel sender unit hole, you can see the internal portion of the fuel pick up does not move at all. Just the exterior barb fitting

[Patcon]

If the outside is loose and the inside pick up doesn't move then you may be pulling air instead of fuel

[grannyknot]

4 hours ago, Dcreech0 said:

I have the tank out. When I wiggle the feed line on the outside of the tank, looking through the fuel sender unit hole, you can see the internal portion of the fuel pick up does not move at all. Just the exterior barb fitting

If it is just moving on the outside then it will be much easier to solder up, just make sure you go through the usual measures for cleaning the tank and purging it of all vapours. I like using the vacuum clear on reverse so it is blowing fresh air in.

[Pop's Z]

Yes, this is the exact same issue I had. I also had a full tank of fuel and didn't want to mess with emptying, dropping, etc. I didn't have a delivery issue, though. Like I said JB Weld "fixed" the problem.

Cheers, Mike

[Zed Head]

I've used JB Weld on a pinhole leak on a Pathfinder.  It was still seeping as I pressed the glob on to the hole.  Worked for a few years then I removed it and reapplied.  If it had been completely dry probably would have worked forever.

They even wrote up a procedure for it.

https://www.jbweld.com/projects/gas-tank-repair

[cgsheen1]

21 hours ago, Dcreech0 said:

I have the tank out. When I wiggle the feed line on the outside of the tank, looking through the fuel sender unit hole, you can see the internal portion of the fuel pick up does not move at all. Just the exterior barb fitting

Hmmm, I was always under the impression that tube was one-piece and soldered (to seal the tank) at the plate it goes through. The plate is soldered to the tank itself. IF the tube is 2-piece, and if it's swiveling at it's solder joint at the plate, it also has to be "disconnected" from to the second piece that remains unmovable while you're twisting the exposed feed tubing. If it's soldered (supposed to be soldered) to the pickup tube inside the tank which does not move, that solder joint is broken also - either that or the tube itself is cracked or broken. Most fluid pumps don't work well if you can pull air into the source piping. 

I've repaired a few 240Z fuel tanks with broken solder joints at the supply and return tubing, but I've never actually de-soldered the plate to remove the entire assembly. So, I don't know if any of that fuel tubing is one or two piece. My only concern in your situation would be sealing the tube on the exterior without checking that all the tube on the interior was "liquid tight" - without cracks, holes, or other damage.