Before you go wrenching on anything spray that fitting down with penetrating oil. I prefer PB Blaster, others like Liquid Wrench. Either will work, never use WD-40.
Spray, tap, spray tap, spray, tap. The oil will soak into the threads and dissolve he rust/corrosion. Tap lightly and the oil will work further in with each tap. Sometimes you have to pull out the propane/Mapp gas torch to heat it up. Heat will make it expand and give more room for the penetrating oil to work.
Plus the oil will lubricate and make removal easier once you break it free.
Been wrenching on my junk for decades. Bought a gallon of PB Blaster when I was maintaining a fleet of 6 vehicles, all daily drivers. Great stuff. I got tired of breaking stuff and trying to drill and tap new holes.
HOI Crappie Club
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