I'm redoing a Focus bucket right now, a whole 'nother world there. They commonly crack the back at top because with the reclining feature they are not anchored on one side, so every time you get in the car you lean against the back internal frame to warp it one way to crack. Common, most in the yard were the same way, luckily I tripped across a lightly used one with no cracks. I brazed a couple of pieces onto it to reinforce the crack areas, with a bit of luck it will hold up under my fat -ss.
My first car seat but it's going well, found a good back support frame and a nice cover and foam support molding as well so back together she goes. $25............
It gives you respect for those who do that work every day........... ...many are old timers and once lost those skills are gone forever.