One problem related to power assist brake has been reported for the 1996 Mercury Grand Marquis. The most recently reported issues are listed below.
2 brake line failures metal brake 1996 Grand Marquis within a year. . This is a midwest car but spent half of its winter in az. . Brake lines seem to rust much faster than other vehicles we have owned. . Failure found driving at slow speed. Took vehicle for repair parts from second repair could be available.