What happens if you hide your car so it cant be repoed?

As a Constable and repo agent the quick answer is simple: If you hide the collateral from a creditor you will find yourself in court as the creditor seeks an order of replevin. It is basically an order from the court forcing you to turn over the pledged collateral or face a charge of contempt. If You refuse and the judge finds you in contempt you can ( and should) find yourself in jail.