Hi Rowa45,
Welcome here,
You will need a decent 2 jaw puller because it could be very tight, rusted on. Some times I have had up to 6 tons on some and they still won't move. The shaft will be threaded, obviously somebody has removed the bolt. I'm not sure of the thread but could be something like 3/8 UNF but that is my guess. It won't be metric or whitworth
