If you're old enough to remember your first all-drum Mercury, you may also remember that it may or may not have had a Mercury brake booster to help you stop. Yet try to find a Montego or Mariner today without a Mercury brake booster and you're out of luck. What happened to make power brakes, and the Mercury brake booster, a ubiquitous part of today's Mercury models? Two things: An increased reliance on comfort features and the advent of disc brakes as standard equipment. As far as comfort is concerned, the Mercury brake booster makes it possible for anyone, from your three-foot thick uncle Kowalski to great grandma Esther, to safely and easily stop your Grand Marquis. Regarding disc brakes, the Mercury brake booster makes it possible to stop your car at all. Disc braking systems, while much more efficient than the drum systems they replace, have no natural assist. Without the Mercury brake booster, you'd find it nearly impossible to come to a stop in any kind of reasonable distance. If your Mercury brake booster has failed during driving, you may have discovered that fact the hard way. Due to age, corrosion, or neglect, the Mercury brake booster (and its rubber components) occasionally gives out, preventing it to hold the vacuum that it needs to operate. The result is an extremely stiff pedal under your foot and vastly increased stopping distances. Fortunately, the problem is easy to fix: Simply buy a new or rebuilt Mercury brake booster from us and install it between the master cylinder and the firewall. There's not much to a Mercury brake booster swap and you can save money when you buy your new Mercury brake booster from us, so at least there's good news too!