Sometimes it's not what you think. if the bar got bent just a bit, it may be pinched or wedges in place. At that point, it's not a lubrication issue. My DH was tyring to get a peice off a pin, and he had to file down the pin a bit as someone had given it a tap with a hammer at some point, and deflected the metal just enough that is was no longer straight and true.
The peice would slip off about 1/4 of the way, and at that point the slight bend in the pin would cause enough sideways pressure that it wasn't going to budge farther without something breaking.