47-55.1 Rebushing rear suspension

[alaska gasser]

I knocked the rear end and springs out of my "52 long bed 3/4 ton and need to install the new brass bushings / pins. Several of the old bushings are worn almost through. One old mechanic told me to file / grind through and then collapse the old bushings to help remove them. Going through them and marking the inside of the shackles worries me. I'm sure someone has figured out the best way to accomplish this task. As well as the best way to install the new ones without distorting them.