Anyone ever put a lien on a car before?

So long story short. I'm trying to get the title to a car that's sitting in my yard that I'm buying. I owe $400 on it. The guy selling it is giving me the run round. And had to find the original owner (also playing games)because the title was never transfered to his name. It's been a month of waiting for a title change, and I'm sick of it. I want to put a lien on it since it's in my yard, and I'm tired of waiting.

What are the steps?