Hello fellow members,
As an update to my sad tale above:
I and a friend managed to remove the entire wiper assembly (a hellish job, as promised!). Suppressing my basic urges to smash the whole thing with a sledgehammer, I mounted the assembly in the vice of fellow member and millwright Sven. It was seized solid on the driver's side. Tapping, application of heat, and lots of penetrating oil did nothing. As a last resort, Sven drilled three holes into the wiper shaft tube and filled them with penetrating oil. I later took a long-handled set of channel-lock pliers, located them onto one bar of the linkage, and applied pressure. Nothing at first, then I detected a slight bit of movement. More penetrating oil into the holes and as the shaft started to move in its tube, even more. With each spray of the oil a brownish foam started to come out, a sure sign of inner rust! Finally I got the whole thing loosened up and working the way it was intended. Then I greased the shafts up with the grease nipple wiper tube attachment described elsewhere in this forum. Now I'm looking forward to reinstalling it all--NOT!