Hy ZB3, You could try using one of your old shackle bolts threaded into the bushing and drive it out with a sledge hammer, or you could use a 1/2" socket just smaller than the O.D. of the bushing and a long 1/2" bolt and the piece of pipe you mentioned to draw them out, it takes a lot of force to get them to start moving, but once they start it should get easier as it comes out, you can use the same method only backwards to install the new ones, hope that helps.
