Purchased Flex March 11, 2016 as a used vehicle with a bit over 28K miles. Within first 2 weeks noticed that the brake pedal would travel all the way to the floor, vehicle still stops but quite unnerving. Took it back to dealer as covered under 30 day warranty. It has been back 3 times and will be going back a 4th time. To date it has had 2 calipers replaced, brake pads replaced, master cylinder replaced, 3 brakelines replaced, brakefluid evacuated and replaced, brake booster replaced twice and finally the "a controller" replaced. We brought it home and drove ok within 12 hours...or by next day same problem existed started the flex, put foot on brake and into reverse pedal went all the way to the floor. Both the dealer (Carmax) and Ford have worked on it yet nobody can seem to figure this out. I have seen on Ford Forum that this issue existed for Ford Flex up to 2012, then they redesigned braking system. How can there not be a recall on this and why can't anyone fix it? Has anyone else had this problem? We are ready to call it quits on this vehicle as we have only driven it for 2 weeks the rest of the time the dealer has had it.