Don't understand me wrong, you have made a COLOSSAL work with this model, it's just awesome, but hinge is a really thin part, it asks to be more thick or with some kind of stiffener.
I will try to repeat my experience with it, but I printed 0.1 PLA and those hinges came off right after I gently tried to fit the detail.
Please tell me, you have printed the details in the position of STL files or you turned them flat? I turned them all to the position they will appear when in car mode, so nearly all the details turned 86 degrees. Maybe this caused thin and weak bridges. I can assume that I also have a scrappy 3d printer, but the edges are neat and all other connections are firm.