concerns about flare fitting on fuel pump and carburetor

[dmjlambert]

I have a 1969 CST/10 with a 350 engine, mostly stock except a GM HEI and a 1986 Quadrajet.

I am replacing the hard fuel line between the fuel pump and carburetor because it was not shaped well, not routed a way that makes it easy to disconnect in order to replace fuel filters, and I think it may have had a problem that requires it to be tightened too much.

The line is a green painted steel line commonly available at auto parts stores. They come long and straight and with double flare and fitting on each end. A couple years ago is when I installed this, I cut it to length and bent it with a tubing bender, and put the fitting on and flared the end. The flare tool and the bending tool were loaners from the auto parts store, in new condition, and worked well. At the time I installed this I had a different carburetor with the inlet at a slightly different position compared to my current carburetor. So the fit is not ideal. Plus, I did a regular flare and not a double flare. The double flare factory fitting was on the fuel pump. I tightened it with the minimum torque required to get it to stop leaking. I had to tighten it very much.

Now fast forward to today. I destroyed the fuel pump in the process of trying to loosen the fitting, it was overtightened a Ridiculous amount. This was the double flared side. I had to use less force to remove the single flared side from the carburetor, but I still think it was too tight. I've been putting off doing this work because I knew I would have a bad time with it. The worst is over, I have disconnected the damned thing. I have some experience replacing fuel pumps so I'm not worried about doing that. And I think bending the new fuel line to shape will also be fine.

My question for you guys is: are there any tips to put the flare fittings on or treat them in advance so I don't have to over tighten them to prevent fuel leaks?