Hi, doing 70 km/h today, hit the brake to stop at a traffic light, pedal snk to the floor, providing absolutely no braking resistance. Almost panicked, but just on the second pump brakes came back, I have had no problems since, they worked fine all the way home. What could cause this?

Is the hose loose that goes from the intake to the booster?Or damaged?

nope, that hose is in great shape.

check fluid level and condition...brake fluid changes are as essential as an engine ol change...im starting with the simple stuff

ok, i should tell you that the entire brake fluid has been changed within the last 7 months. car has a new caliper, two new rear wheel cylinders, brand new rotors and pads, a new drum... could it be the brake hoses? they are about the only thing i havent changed.

How'* the fluid level?

right up.

Were the brakes bled properly?

Sorry if these sound like dumb questions. Just covering the basics.

Yes, but not since the fall. Only thing I've worked on recently is the Rotor and pads, last week.

90% chance that'* the master cylinder failing. There will be no outward signs of it.