one step forward two steps back

[Ray]

I'm getting so close to being done with my 46 restoration and I filled the left tank and it is leaking slowly, now I have to disconnect everything and try to tighten it again. Has anyone had this problem before. It is leaking at the AN fitting and the flare. Thought I got it tight at least I hope that is it.

[Pearson]

Re: one step forward two steps back

Ray,

I am very sorry to hear of your troubles. I know how disheartening it can be. I had a leaking wing tank too. I tried tightening it, but quickly realized that it wasn't comming past the threads, but around where the fitting was welded into the tank. Did you put any fuel lube on the threads? It makes a world of difference. If you didn't, I suggest you drain the tank and put a very small amount of fuel lube on the threads. Just be sure to not get it near the end of the line where it could get into the fuel system as it can clog it up. I would be very careful about overtightening. The wing tanks are made of very thin metal. If you find you need to remove the tank there is a 337 on the website for replacing the fabric over them with sheet aluminum.

[Ray]

Re: one step forward two steps back

Where do I get this fuel lube

[Pearson]

Re: one step forward two steps back

Right here; http://www.aircraftspruce.com/catalo...ezturnlube.php

[barnstmr]

Re: one step forward two steps back

Ray,
Sorry to hear about your setbacks. But glad to hear you are on top of it and doing the right thing by addressing it now. just one piece of advice... I hope you don't learn this the hard way like I did. BE CAREFUL WHEN TIGHTENING LINES. DON'T OVER-TIGHTEN FLARE FITTINGS OR THE LINE WILL CRACK IN THE FLARE. This is especially true with aluminum tubing.

Do you still have the original valve at the wing root? Those old valves have an odd old style internal male flare 45* inside female straight threaded boss. This is designed for a 45* female flare and a nut with male straight threads at the end of the tube. If you still have this old style valve, it is hard to find the right fittings. They are an old natural gas standard that is obsolete. I think there are certain AN type fittings with male threads that can be threaded into the straight thread on the valve boss but requires an O-ring seal against the valve and the other end is a 37* aircraft male thread. maybe someone can chime in with some photos.

[mikeg]

Re: one step forward two steps back

I got about that far on a '46 restoration and found the main tank fitting boss cracked where the fitting had been overtightened (aluminum tank and fitting boss).
Mike

[Ray]

Re: one step forward two steps back

Well the fuel lube and cleaning the fitting worked, it appears. It had gasoline in it for 4 hours before I left the hangar, with no visible leaks, Will know for sure tomorrow.