To remove the bushings in my flange I placed a socket that was slightly larger that the insert. Then I threaded a bolt (with a washer) through the socket into the insert. Screwing the bolt in drew the insert out. I may have squirted a bit of WD40/LPS on it beforehand.....it was last year so my memory is not 100%.

To put in the new ones I did the same thing but from the opposite side of the flange.