Yesterday I pulled a used right rear trailing arm from the W126 parts car subframe I had at the ranch. The W123 wagon uses the same part as the 1st gen W126s. I just need to swap out the park brake cable. I'll have to study that...

This trailing arm will solve my wheel bearing issue since I don't have the tools/time to rebuild the old one. I'll go ahead and press new bushings into it before it goes back on the wagons subframe.
I need to make a tool to do this. Tried the Autozone ball joint press on one of the bushings. Got one out but it is way too cumbersome...

I think I can make something with "all thread" washers and a piece of pipe.

I'll try to go back and edit and post pics when I'm finished.

FYI, This car has approximately 210K miles and has been well maintained. I found the rear trailing arm bushings to be hard and crumbling. I was beginning to drive and feel as if the rear tire pressures were low. A bit of wandering.