In a medium bowl, toss steak with flour until all of the steak pieces are well-coated with flour.
In a large skillet over medium heat, warm the oil. Cook the garlic in the oil for 30 seconds. Add the flour-coated steak to the skillet and cook until the meat is slightly browned on the outside, about 4 minutes. Spray with cooking spray if there is not enough oil in the skillet.
In a slow cooker, mix together the water, V-8 juice, ketchup, cider vinegar, sugar, salt, and pepper.
Add browned steak, potatoes, carrots, and onions to the slow cooker and mix into the sauce.