With our elevator, I had issues with the motor stalling out and tripping the breaker at one point. I took the motor into a guy who rebuilds them. He replaced the start switch, a capacitor a couple of rusty bearings (IIRC) and it worked fine again.I'll start by lubricating everything. Then next time I have a load of hay I'll make sure to try and find out exactly what's binding up before I mess with the motor.
Are you sure the belt isn't slipping when the elevator stops moving? If the motor stalled, I would think that it would blow a breaker or activate the thermal overload in the motor.