LIGTHLY APPLIED BRAKE TO SLOW DOWN TO STOP AT INTERSECTION; THOUGH I HAD FOOT PRESSING HARD ON BRAKE CAR WOULD NOT STOP, ENTERED INTERSECTION AND STRUCK A PASSING CAR; THIS WAS WITHIN AN HOUR OF PICKING UP THE CAR FROM GARAGE WHERE REPAIRS HAD BEEN DONE BECAUSE OF THIS PROBLEM; AIR BAGS DID NOT ACTIVATE AT IMPACT