The bolt used to extract the eccentric pin does not need to bottom out. It needs only to thread in a few turns to grab hold of the pin, then pull the pin out. I use a longer bolt (instead of the axle pinch bolt) from the hardware store, for a better grip. Just get the same thread (M6?). Sounds like your pin is a bit stuck. But, it also sounds like the pin rotates freely, so I don’t know how it could be stuck. I’d get a longer M6? bolt, so you can get a better grip, and I bet it will pop out. 

If you don’t want to look for a bolt at the hardware store, take out one of the bolts that holds the fork reflector and front fender bracket. It’s the same thread, but much longer. 

Good instructions there.

Part of the lesson here is that you need to reassemble the caliper and pin with lots of fresh waterproof grease for the next owner/mechanic. Those packets of silicone brake mechanism grease that come with car brake pads work great.

@wobbly Thank you David and Richard for your responses and suggestions. A few hours ago and with the help of some liquid penetrating oil and a new found vocabulary I was able to extract the pivot pin and the caliper. Man oh man is the price of neglect and abuse high. In an effort to remove the RH caliper piston I discovered that the previous owner "ran 'er hard and put 'er up wet". Piston was, in large part 'frozen' in place. Mucho compressed air and the aforementioned liquid penetrating oil are ever so slowly working their magic. The beat goes on...