Drawtite 5th wheel hitch - Linchpin

[swbouton]

I need to separate the head from the base of my fifth-wheel hitch. The problem is that I can't turn the linchpin in order to be able to remove it. It is currently soaking in WD-40. Any ideas?

 

[swbouton]

Finally got it. Beat Hell out of it with a small sledge hammer, broke up the oxidation with WD-40 and twisted it with a good vise grip.