Judgement or not, you will not be able to tow away someone else's vehicle without having the police involved.

This is the process. Small Claims, by nature, is for petty disputes between citizens.

Perhaps append "in California" or whatever jurisdiction you are in.

These are local and state matters: some states respect private property and contractual arrangements more diligently than others.

I don't know of any state or jurisdiction where you would be legally allowed to just show up and tow away someone's property without involving law enforcement in some capacity.