Make sure and change the little screws that hold the motor on as well. On the 89 I had changed the bushings and then about a year later the screw head popped off and the motor tore up the brushes on the inside. This was about 4 years ago and since I don't drive it much I still haven't fixed it. It wouldn't have been an issue if I had changed them in the first place to SS or something else. Two screws per motor, you can see one in this picture next to the white and green wires:
Don't get cheap like I did or just think they will hold. Spend a few cents and be safe. The ones on the 89 looked no worse than the ones pictured above.
Daniel