I will be arriving into Strasbourg at about 2:00 pm on a Friday, after lunch service stops in most restaurants.
I have never found or even heard of a good brasserie which would serve the complete menu all afternoon-like those in Paris.
Since Strasbourg is kind of touristy as well, mainly around the cathedral, you'll find plenty of brasserie-style restos that serve all day.
A less touristy place is La Chaine d'Or, however with a limited menu in the afternoon.
Another really nice place, mainly the outdoor area, is La Corde à Linge close to Petite France with some typical Alsatian dishes. Hard to find a table though.