Best practice would be to replace them both - in theory, if one has gone bad, the other is probably going to fail soon too. Flush out the brake system with lots of fresh, new brake fluid too. Take a good look at the rotors - if there's been a problem with the calipers, it's likely that the rotors have suffered too - usually overheated and warped.
Mercury Grand Marquis
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Maintenance & Repair
How to remove rear brake caliper there are no 10mm bolts
1994 Mercury Grand Marquis LS Sedan RWD
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Maintenance & Repair
My 2002 Mercury Grand Marquis is a fantastic car. About a year ago I noticed that if I don’t park with the front end higher than the back it might take 2 or 3 cranks to start. Otherwise it starts ...
2002 Mercury Grand Marquis LSE
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Maintenance & Repair
Driver seat doesn't operate. It will not go forward or back up or down in it is stuck in a reclined position please help
2010 Mercury Grand Marquis LS
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Maintenance & Repair
All kinds of running problems, but this possible brake issue is bad, after a mile or so of driving the car starts pulling left driver side, then a mile more car starts draging & bucking, vibration, I'...
1987 Mercury Grand Marquis LS Sedan RWD
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Maintenance & Repair
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