In a large resealable plastic bag, combine flour, salt and pepper. Add beef, a few pieces at a time, and shake to coat. In a large saucepan, brown beef in oil; drain. Stir in the cider, water, vinegar and thyme; bring to a boil. Reduce heat; cover and simmer for 1 hour and 45 minutes or until the meat is tender. Add the carrots, celery, potato and onion; return to a boil. Reduce heat; cover and simmer for 45 minutes or until vegetables are tender.