They are actually studs that you will have to replace (if it’s what mine has). If there is anything sticking out Snap On, Matco, Mac make a tool to grab the outside and remove them. Seems to me Sears makes one too. Also you can centerpunch and drill a 1/8″ pilot hole, then get some left handed 1/4 or 5/16 bits and use an Easy Out. Sometimes just the left handed bits will loosen and draw out the studs. Better you than me When I broke mine I snapped the crappy welds on the bracket instead, much easier to repair.
Edit: Pepage beat me to the post, his idea will work too if you have a hot enough welder, and you won't have to buy any tools.