Dartin for Divorce

... maybe if they keep it up apply some sealer... don't judge me.

I won't judge you, but it also won't work. If the flare fails to seal, sealer will get blown out by the pressure. It may look good after a couple pedal presses, but will fail soon after.

Since you found one suspect nut, I'd check the others and their flares. They don't leak for no reason ;)