¡Ay, Jalisco, no te rajes! (Jalisco, don’t back down!) is a 1941 film directed by Joselito Rodríguez and starring Jorge Negrete. The film site Sensacine México calls the title “una frase nacional” (a national phrase) and “una declaración de carácter” (a declaration of character).
Rajarse is one of the Mexicanisms recognized by the Academia Mexicana de la Lengua. It means “retractarse, o faltar a una promesa” (to back down, or to break a promise).