My son was mowing on our John Deere la145 and before he finished he brought it home with a broke mower deck belt. He said the belt broke while mowing the grass. After I put a belt on it when I tried to engage the mower it acted like it was in a bind and killed the motor. I tried several times to engage the mower and it did the same thing ever time. I looked under it hoping to find something wrapped around the blades putting it in a bind but there wasn't. What could be causing this to happen.

Hi,
Broke your post free from where you put it. Remove belt, engage deck and check spindles for free rotation. Could be a bad bearing or broken spindle housing. Coule also be that the spindle brakes are not releasing.
Peace,
Clarke