[eeedelli]

Originally Posted by c1800

Heat and reheat, interspersed with application of penetrant. Also try and tighten the connection, then loosen, sometimes that will break up the corrosion and allow penetrant to enter.
Many swear by a mix of ATF and Acetone as a penetrant, more effective than off the shelf products.

Yes I suspect I'll have to try more of what I've already been doing, though it hasn't done much, so far. The snag is that the female end points downward (and the bracket and spring clip are in the way too) so it's pretty much impossible to get anything up there into the threads.

Thanks for the thought.