Following a steady increase in students in the late 1950s and the resulting overcrowding, OLQA engaged in an ambitious expansion program, opening a second, adjacent campus in 1964 that effectively doubled the size of the school.

Although the overcrowding problem was solved, the school soon suffered a steep decline in the number of students, a reflection of national seminary trends following the Second Vatican Council.

At the present time, the former East Side campus is used as the Administrative Office of the San Fernando pastoral region of the Los Angeles Archdiocese and as a preschool.

With the departure of the Vincentian Fathers, OLQA entered a new era under the administration of diocesan priests appointed by the Cardinal Archbishop.

Due to the decline in enrollment, the lack of students advancing to the priesthood, and the increasing financial pressure on the archdiocese, the decision was made to close the campus, effective July 1, 1995.