I found this post while attempting to resolve the same issue for replacing the wiper motor bushings. I came up with an even easier and less destructive approach to do the rubber bushing swap while keeping the original ground strap in place. Here are the steps:
1. Find the rubber bushing with ground strap on the wiper motor. Do not remove or tear out the any part of the rubber bushing assembly.
2. On the back side of the rubber bushing (i.e., firewall side) you can see the steel bushing inside the rubber bushing. The tip of the steel bushing has been pressed so that the lip widens and pushes tightly against the rubber bushing hole ID. The only purpose of the widening is so that the rubber bushing does not fall off the steel bushing when it's shipped loose or before it's fastened up against the firewall in the installed position. When the rubber bushing is in it's installed position, the rubber bushing is tightly secured in place between the steel bushing washer (on engine side) and the firewall, so the widened tip of the steel bushing no longer serves a purpose.
2. Given the conclusions in step 2 above, take a small needle-nose plier, open up the plier, and carefully wedge each plier tip between the rubber and steel bushing joint (1st photo).
3. Carefully squeeze the plier and crimp the steel bushing lips slightly (1st photo). Do this procedure twice or three times at equidistant spacing around the bushing circumference. What you've essential done is reduce the widened steel bushing lip diameter so that the steel bushing can slip off the installed rubber bushing from the front side (engine side).
4. Take a flat head screw driver and pry it off slightly to get it started before you pull it with the plier (2nd photo). Take the needle nose plier and pinch the wide steel washer of the bushing and pull it off the rubber bushing if it won't come off using the screw driver (3rd photo).
5. Pull the rubber bushing off the wiper body and the ground strap will remain in place (4th photo).
6. Take the new rubber bushing assembly and crimp the back side of the bushing as in step 3 above. Don't crimp the bushing too much or the mounting screw won't slide through.
7. Remaining steps for new bushing install require only steps 5 and 4, in that order. There is no need to go back and widen the crimped steel bushing tip since the rubber bushing is secured in place once wiper motor body is installed.
This repair keeps everything looking original, like it never got touched. No need to widen the wiper motor body rivet tabs and risk breaking them as in previous post above!
Good luck, guys!