I recently bought a 2012 that I am having trouble with the brakes on. I stepped on the brake pedal and it almost went to the floor. Then everything went back to normal. I tested the master cylinder and it passed so I changed the fluid and bled the brakes. All was well and then a few weeks later I hit a bump on the road and it happened again. This time I had to pump the brakes several times to get the pedal firm again, but everything went back to normal. What could it be? I retested the master cylinder and it was fine. Never heard of an intermittent master cylinder failure.