1985 Ford Bronco Four Wheel drive

the grinding is usually either brake related or wheel bearing related. a broken hub only grinds for a little while. the steel parts of the hub quickly eats the aluminum parts of the 4x4 hub and you rarely hear it anymore. check the brakes first. the wheel bearings and hub are also easy to tell by turning the wheel or rocking the wheel. it shouldn't rock and should turn smoothly. lock the hub and do the same thing. should be easy to narrow down. with the hub locked when the wheel turns, the axle ujoint will turn and you can see it behind the wheel. good luck.