Sealing inverted flare fittings

[VintageMusclecar]

I'm often questioned what's the best/easiest way to get an inverted flare fitting on a fuel line to seal up, especially when using new components.

Here's a quick & easy tip;

A little daub of heavy grease (such as wheel bearing grease) on the back side of the tube where the component contacts the back side of the flare and some on the threads of the component as well will make getting these fittings to seal considerably easier.



When these components are new, the flare on the end of the tube needs to be compressed in order to seal against the flared seat. More often than not, the friction between the component and the flare becomes the limiting factor when trying to tighten the component. The grease eliminates the friction against both the flare and the threads, and most of the time the new flare fitting will seal on the first try.

If it doesn't seal on the first try, gently tightening and loosening the component and slightly rotating the fuel line (or whatever other component you're working with) between each tightening/loosening will usually resolve the issue.

Another added benefit is the grease will prevent corrosion at the junction, which makes subsequent removal (as in "years later&quot far easier as well.

Lastly, a friendly reminder:

The threads play absolutely no part in the sealing process on a flare fitting, so leave the Teflon tape in the tool box.

Hopefully someone will find this helpful.