You could always try to double nut the pin to remove. Soak the pins with a penetrating oil for several days and tap the pins lightly with hammer occasionally, soak some more then try the double nut trick. Patience pays off with this method.
Thanks Phil. I have sprayed PB Blaster on the pin and tried the double nut method. They are in solid. Just not a good surface to grab with vice grips or channel locks without destroying the thread. Last thing would be heat, but I don't have a torch handy. I will of course try again today before moving forward. I may be overthinking the potential weakness of the shackles. I don't have a lot of experience with them to know if the stresses are significant enough to cause the shackle to bend or twist. I imagine the version with the nuts on the pins exists for a reason.
