I suggest starting a new thread if you don't get a lot of responses.  This one is 3 years old. 
  
Check the fluid level and look for leaks around the master cylinder and each wheel.   Could also be air in the system requiring a bleed.  If none of that pinpoints the problem then it's probably the brake booster.  Do a search - it's happened to a few folks. 
  
Also - it's pedal and engaged.  (sorry, pet peeve).