Brake issue

[tom8787]

Have a 2011 Insigina, no issues with brakes, went to drive it this morning, brake pedal went all the way to the floor, and made a "SHHH" sound, after pumping it (each time the travel got less and less ) they did go firmer but then were the same after 30 seconds, I have check pipes and all seem OK, fluid level is fine, and is not dropped. 

Any ideas ?  

[Vauxhall Owners Club]

It could be that the master cylinder is faulty - leaking between the internal seals.
Check also that the brake servo is working correctly by running the engine and switching off and pressing the brake pedal about three to four times and the pedal should get harder and higher up. Hold the pressure on the pedal and start the engine and the pedal should drop down which means the servo is okay.

If there is no external leaking of brake fluid then I would suspect it is the master cylinder at fault