1972 Plymouth Duster

Thats a good question. I have not taken the seat out of the car.

The backrest on the passenger side gets completely off-track when I pivot the passenger backrest forward to allow anyone to get access to the backseat.

It looks like the entire passenger backrest needs to come off to determine what is mis-aligned or not engaging?

Does the factory service manual show a detailed exploded view of the center arm rest and the front seat/passenger backrest components?