I just had one of those on a similar Hyster. Found the pin was frozen most where it goes through the frame. It's bad design because the pin had to be driven out from the inside and it was impossible to get a straight shot at it. Removing the accelerator assembly gets you a little better angle. In the end I had to drill (1/2") it out in order to get good heat to the center of the pin, use buckets of penetrating oil and use a Snap On air hammer to get it out. A portapower cylinder would fit in at an angle but it was of no use.

Don't know how you are using the heat but the method I use most is to heat everything, pin included, to just short of melting then letting it all cool back down before oiling and pounding again. Had to do that three times on this last job. After 8 or more hours of beating on this one I was just about ready to completely drill it out or torch it out when it finally gave way.

Also, I noticed that a socket would fit over the flat on the pin but I doubted that would have worked considering how badly it was frozen. Maybe try using an impact on the rod-end pin to see how it works. (though the rod-end should be an easier one to get out. )

I wish you luck with it.