Before Chris Weitz was the director of “The Golden Compass” and “New Moon,” he was the grandson of Mexican silent movie star Lupita Tovar. Does that entitle Weitz to a pet project updating the Italian neorealist classic “Bicycle Thieves” as noble-immigrant melodrama in today’s East L.A.? Well, sure. This rather pat but nicely acted and nicely location scouted film, written by Eric Eason from a story by Roger L. Simon, concerns an undocumented single-dad day laborer (Demián Bichir) struggling to keep his teenage son (José Julián) in school and out of a gang. At its best when father and son forgo trite-tending Spanglish dialogue in favor of more genuine nonverbal communication, Weitz’s movie does get across its sincerity and sympathy for their fragile standing within the community and each other’s lives.