If I file bankruptcy and have a lien on my old car, what will happen can the lien be removed?

It depends on the type of lien.  If this is a judgment lien, it can sometimes be removed, but it depends on the value of the vehicle and the amount of any senior liens, as well as other factors.  If you're talking about a purchase lien, it can't be removed, but you may be able to reduce the amount owed down to the current value of the vehicle.