Okay so I am new to this but I have been reading threw some of the threads on this topic. I have not been able to find anyone who has experienced a similar issue. I am looking for guidance as to what the issue may be. So on my way to work today and the check brake system light came on. I go to touch the brakes to see if they will work to stop and the pedal goes no where. It was stiff and took some effort to depress enough to slow down. I got out and messed with the wire that connects to the master cylinder, fluid level was good. Get back in start the truck still having the same issue. Turn it off and let it sit for a few and the issue went away. Made it about 5miles down the highway and back to having the same issue. I pull up recalls and there is nothing for this truck. The recall is for aug 13- aug 14, the truck was bought new in April of 13. It does have the 3.5l that the recall is under. Going to try to pull the code here in a few and see what it’s says, but has anyone else experienced a similar issue.

 

I had the same issue tonight, on my way home from work. Check Brake System warning came on, and the peddle had a lot of pressure behind it. It took a lot of force to engage the brakes. I pulled over, parked and shut the truck off for about 3 minutes. When restarted, all was normal and I drove home without further incident. Two weeks ago, the Ford dealership replaced the vacuum boost on the passenger side of the engine. That's all I have for now.