fairly common, usually when the grass gets tall and bunches up under the deck.
belt is on on the deck. A belt comes off the engine and around pulleys that spin the blades.
Any more info on the mower like a model number? should be located under the seat
Troy Bilt made a lot of Bronco mowers, remember there's a couple hundred miles and a screen between us and you so a model number is always handy so we can look at diagrams for the machine.