The spin cycle doesn't work, How can I fix it?

The spin cycle doesn't work, How can I fix it?

I have an old belt drive Kenmore 70 Series washer. The water drains from the tub, but it will not spin. The motor operates and the belt turns, but the tub does not spin. I have seen YouTube videos on how to fix the motor coupling on a direct drive washer, but I cant find any info on a belt drive washer. Does anyone have any advice?