The roll pins and shaft,on the older models, are designed to be rebuilt one time. Take everything off but the bottom and the shaft, stand the shaft on a piece of wood and drive the top roll pin into the shaft. The shaft is bored to let one roll pin slide into the shaft. Slide the shaft out of the bottom and do the same thing to the roll pin on the other end.
If the roll pin won't move,(hit it hard) the press may have already been rebuilt and it's almost impossible to take the roll pins out.