loss of brakes

[arbyp]

I have new brakes all the way around vehicle but a couple of times when I went to apply brakes the pedal went right to the floor, after pumping them up it worked fine for a couple of weeks until it did it again. any help would be appreciated.

[KimMG]

There is either air in the system or the master cylinder is failing.

[Johnny Mullet]

Or you have a leak. Is the fluid low?

[JoeShmoe]

Yeah sounds the master cylinder but you definetly want to check out everything the guys posted. Brakes aren't something you want to forget about.

[arbyp]

fluid is up and can't find any leaks, how do you check the master cyclinder

[rhandwor]

Hold down on the brake pedal does the pedal stay up or go down gradually. Your symptons sound like a master cylinder unless you did brake work recently and didn't bleed properly.
Go to a parts store and purchase a rebuilt unit. This is only if you know to bleed the brakes.
Otherwise go to a good garage and get it done. At some point you will hit the pedal and ram a police cruiser.
This will really make your day.