if it's the car in your avatar it's because the studs are swedged in and you need to remove the swedge before you pound the studs through to the back side. it will open up the stud holes if you don't and you'll be unable to press backm in original style studs. I'm assuming your talking about the fronts (that's where they are swedged on at). I have not looked at the rear setup in a while and can't comment on those.