Some people go to the trouble of removing the brackets and then rewelding them with the bushing in place.
I have always just lubed them up with WD -40 start them first at the top of the triangle part of the bushing and work my way to the bottom on each side. I use stong language, channel locks, large plyers, and large vise grips to get them to go in.
It is rough but it can be done.