The strut rods gave me fits. What will usually happen is that one end will loosen and the other end then has nothing to pull against, so it's a bear getting the second end loose. Chryco had suggested to me heating the tight end with a propane torch. I also ended up putting a pipe wrench on them to keep them from turning (with the jaws wrapped with shop towels so I didn't mess up the strut rod too much).
One more thing: WD-40 is really a water displacer. To loosen stuck fasteners you need a penetrating oil, something like Liquid Wrench, which will work its way into the threads. If you've got a tough one to remove, apply penetrating oil directly to the thread area and let it sit overnight.