Mark is the guy for this, I don't know much about pump repair, hoping he will chime in. I know this, there is an order to how all the parts go together. I know you are thinking new pump from your other post.

Speaking of Mark, he has a great article about pump run time. You don't need to run your pump 12 hours, you could get away with less, like 1-2 hours twice a day. I know you have a lot of debris that gets in your pool, so that might be why you run your pump so much more.