This should apply to all Subaru wagons, including the OBS, Outback, Impreza and Legacy.
Problem: You have a 90s or 2000's wagon, and your rear wiper is rusty and generally pretty crappy. What's your option? Buy a used, junkyard arm and try to recondition it? Buy a brand new arm from the dealer and pay out the nose for it?
Here's a solution that gives you a new arm, for a few bucks and some time, and when you need to replace your blade you go visit a Honda dealer and pay $3 for the blade.
Waitaminute, a HONDA dealer?
Oh yes!
See pics below for details, but essentially you will remove your old wiper arm entirely, and replace it with a newer arm + wiper combination from any late model Honda Odyssey or Pilot:
Old arm + new arm already installed:
Old arm showing the open hole where the arm bolts onto the wiper motor:
New arm showing the identical open hole and the 10mm nut:
Parts:
(last pic shows the original nut from the Legacy, the part number is for a new $0.05 nut from Honda)
Any questions, let me know, but if you can change your oil you can do this mod. Shoot if you can do this mod you should be able to change your oil!