[Shane826]

Regarding brakes holding the tire- Remember the voltage/amperage to the brakes does not directly apply the shoes against the drum. It energizes an electromagnet which grabs the front face of the drum. The rotation of the drum tries to spin the magnet, which in turn rotates an S-cam, which in turn applies the shoes to stop the drum. So if the drum isn't rotating, there is no stopping power. In your car when you yank the park brake that cable directly spreads the shoes and wedges them against the drum, holding the car in place.