I have done this job 4 times already. No grinding. Just punch it dead center and use a drill press to drill out the old busing from the arm. Install the new bushing facing the correct direction. I use a 7mm socket under the plastic side of the bushing to brace the metal core of the bushing while I peen the other end. Prop the armature up and peen against an anvil or vice. Easy job. Don't let people make you think it is something difficult. It should take you no more than an hour to R&R the regulator. Add 30 minutes to grease the slide and for door panel dis/assembly.

Don't waste your time farting around with other "fixes" for the slide bushing. They don't last.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge