Bought a 1990 Bronco II from one of my troops and
It sounds like you may have a brake caliper sticking (if the issue is really coming from the front). Does it pull in one direction? One way to check is to jack the front end up and try to spin each tire by hand. They should turn relatively freely. Another possibility, and more likely from your description, is that the rear emergency / parking brake may be frozen. Drum brakes, by nature, do a better job of holding the vehicle from rolling forward. If your emergency / parking brake is engaged, either frozen or inadvertently left on, I would expect the symptoms you describe- moving in reverse, but not forward. You can check this the same way- jack up the rear end of the vehicle, put it in neutral, and try spinning the rear tires by hand.
Assuming your vehicle is a 4x4, a less likely scenario is that something's gone awry in the transfer case, front differential, axles, hubs.
1990 Ford Bronco...
on Feb 03, 2011