2010 Chrysler Pt Cruiser

I STOPPED AT OUR HOUSING DEVELOPMENT MAIL CENTER. WHEN I BACKED OUT, THE BRAKING HAD LOST ITS POWER ASSIST AND I HAD TO APPLY A LOT OF PRESSURE TO THE PEDAL TO ACHIEVE A MINIMUM OR BRAKING. I TOOK THE CAR TO A NEARBY GARAGE AND THEY QUICKLY NOTED THAT THERE IS A 3 WAY CHECK VALVE IN THE VACUUM SYSTEM THAT GOES TO THE BRAKE CYLINDER AREA. FOR WHATEVER REASON, ONLY A 2 WAY VALVE IS NEEDED AND A RUBBER CAP IS PLACED OVER THE UNUSED PORT AND THIS CAP HAD SOMEHOW CAME OFF. WHEN I RETURNED TO THE MAIL CENTER, I FOUND THE MISSING CAP WHICH IS A SOFT RUBBER WHICH OBVIOUSLY IS INADEQUATE FOR THE PURPOSE. THE MECHANIC SAID HE DIDN'T SEE WHY CHRYSLER USES A 3 WAY WHEN A 2 WAY CHECK VALVE IS ALL THAT IS NEEDED. HE ALSO POINTED OUT THAT THERE ARE TWO SUCH VALVES, BOTH WITH THE SOFT RUBBER CAP ON THE UNUSED PORT. HAD THIS HAPPENED ABOUT 2 MINUTES SOONER I MIGHT HAVE CRASHED INTO THE COMPOUND GATE AND IT CERTAINLY COULD HAVE BEEN VERY SERIOUS AT HIGHER SPEEDS SINCE SUDDENLY, YOUR BRAKES HAVE APPARENTLY STOPPED WORKING. *TR