I just watched the video (great video), and think I noticed one step I may not have done correctly. I think I have the "parking brake strut" (the bar with one end having an oval spring) connected to the both pads housings. It appears in the video that the end with no spring should actually be pushing into the parking brake bracket, not the rear pad housing assembly. Make sense?
'68 428 HO M3 Monster, 4-on-the-floor! Need I say more?