To protect the springs, upholstery and trim and to make the rear seat backrest stronger, a cardboard panel is mounted on the rear seat frame.
When you restore the back seat, you will discover that this cardboard panel is well worn, it is rare that it can still be reused.
The rear seat backrest does not have a trim like the other seats, the cardboard serves as protection and finish. Originally, the seat panels and rear seat panels were made of pressed cardboard. The reproduction of the file mentioned here is made of hard cardboard (fiberboard), much stronger than the standard cardboard.
Useful information from Paruzzi magazine and from our YouTube channel :
Look for more technical articles on the page Paruzzi Magazine