One problem related to brake master cylinder has been reported for the 1996 Mercury Grand Marquis. The most recently reported issues are listed below.
When the brake was applied the brakes would momentarily work, then the pedal would go to the floor. The only to keep the automobile stopped was to shift into neutral and apply the parking brake. I had to shift into neutral because of the automatic parking brake release mechanism. Although the car has only 21k miles on the odometer the 36 month warrantly expired technically on 23 may 1999. I bought the car from the original owner on 28 may 1999 after he had the transmission replaced under warranty. The car was disabled for most of the month of may. I asked the Ford motor company assistance number (800) personnel to cover this brake failure because the brakes would have failed in the 36 month warrantly period had the car not been in the repair facility so long. They refused. I had troncalli Lincoln Mercury complete the repair of the brakes which they determined to be a defective master cylinder.