How did this work? upside down brake actuation arm?

[Tom Wesenberg]

I would take the drums off and check out the complete service and parking brake assemblies. At the very least the brake cams will need to be changed (flipped) when the arms are installed correctly. The cams will need to be flipped so they spread the shoes when the arm is pulled forward.

Also be sure the arms are on the correct sides. The opening for the rod is angled to match the frame taper.