It shouldn't be that simple to slide out. It is much easier to use a press to push out the old stud and push in the new one. Otherwise you have to pull the new one in with lugnuts and pound the old one out with a hammer. ( possibly damaging the hub or stud keeping it from coming out....Don't ask how I know!)

 

Craftsman makes a stud puller/installer kit.

It makes it really easy.

 

exactly the brake shield gets in the way therefore the hub must be removed