[C320-list] Furling main control line

[Christian]

As David mentioned, PB Blaster.  Spray liberally, let set over night to
possibly penetrate the thread.

Before you try heat, I've generally had good luck with a hand impact driver
on seized screws, like:
https://www.amazon.com/ARES-70006-3-8-Inch-Manual-Reversible/dp/B01F5XOFFM/ref=sr_1_1_sspa?dchild=1&keywords=impact+driver+hand&qid=1603211763&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUExTzlMRlJSWERZSkJLJmVuY3J5cHRlZElkPUEwMjk5MzkxSURSTjdRTTg4Q1AzJmVuY3J5cHRlZEFkSWQ9QTAzNDI2NzFNU1hJVURIN0RaRjcmd2lkZ2V0TmFtZT1zcF9hdGYmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl

If you've never used a hand impact driver before, ensure it's set to the
correct direction before use, and "cocked" before impacting it with the
hammer.  What's nice about these is the shock of the hammer can help break
any of the corrosion that might be set on threads, helps transfer the
momentum to the entire bolt rather than just the thread, and can bite into
a partially stripped phillips head.  After a few good whacks, if still no
dice, consider heat approach.

If you get it out, on your next bolt, apply some teflon coat to the screw.

-Christian Caperton
1994 C320 #138 "Canuck"
Monroe Harbor, Chicago, IL