Crockpot Swiss Steak

2 round steaks, about 1/2 lb each, cut 3/4 inch thick
1/4 c flour
1/2 t pepper
1 large onion, sliced
2 carrots, sliced
2 stalks celery, chopped
1 can tomato sauce

Cut steak into serving pieces. Place flour, salt and pepper in plastic bag. Add steak pieces a few at a time and shake to coat. Place onion slices in bottom of pot, steak on top of those. Top with carrots and celery and cover with tomato sauce. Cover and cook on low 8-10 hours.