DAUGHTER WAS DRIVING NORTH ON WILMA RUDOLPH BLVD AT 45-50 MPH IN CLARKSVILLE, TENNESSEE AND ATTEMPTED TO SLOW DOWN WHEN BRAKES DID NOT APPLY. SHE ATTEMPTED TO GO AROUND THE VEHICLE IN FRONT OF HER DIRECTION OF TRAVEL AND REAR-ENDED THE VEHICLE ON THE RIGHT FRONT PASSENGER QUADRANT. UPON REAR-ENDING THE VEHICLE, SHE HIT HER HEAD ON THE STEERING WHEEL THEN A SPLIT SECOND LATER AS HER HEAD WAS RETURNING TO THE UPRIGHT POSITION THE AIRBAG DEPLOYED. THE AIR BAG DEPLOYED "AFTER" AND "LATE". THIS AIRBAG WAS PART OF A FORD RECALL AND HAD BEEN REPLACED AT OUR LOCAL DEALERSHIP. ADDITIONALLY, THE VEHICLE HAD THE BRAKE SYSTEM SERVICED IN DECEMBER OF 2018 AND WE HAD INFORMED THE DEALERSHIP OF BRAKE SYSTEM FEELING "SPONGY". THE DEALERSHIP COULD NOT FIND ANY ISSUES WITH THE SYSTEM.