Pfaff 1222 sewing machine

Question

My wife has a Pfaff 1222 sewing machine which I have a question as whether there may something wrong with it. The hook mechanism drive shaft and gear, should it move back and forth if you pull and push on it. If I grab hold of the bobbin case and hook assembly and pull hard it will come out a little bit and then if I push on it, then it goes back against the housing. If so can you tell me how to fix it.
Thank you