My Mom had one of these when we were kids. One day she was picking up my sister and I after school, we were about eight or nine years old and climbed into the back tailgate area, no seat belts of course. The school was in a hilly area (Toland Way Elementary in Los Angeles).
As she backed out of the drive the brakes failed and we went shooting down the hill going backwards, My sister and I had a front row seat. I can't imagine what was going through my Mom's mind but she skillfully maneuvered the car (backwards) into a tall bushy hedge next to the Sparklets plant.
My sister and I just bounced around with no injuries.