1998 Lexus GS300

5/13/1999:TOOK CAR IN FOR 10K CHECK-UP. ADVISED DEALER THAT I WAS EXPERIENCING A FRONTEND SHUDDER AT HIGHER SPEEDS OR UPON ACCELERATION. DEALER ROTATED TIRES AND FOUND NO SHUDDER. 5/14/99:AFTER GETTING ON FREEWAY, EXPERIENCED A LOUD HUMMING AND THUMPING NOISE FROM FRON-END AND A VIBRATION IN THE STEERING WHEEL. BRAKING INCREASED VIBRATION. MY HUSBAND THOUGHT THE LUG NUTS WERE LOOSE ON THE TIRES AND GOT OFF FREEWAY AND CHECKED TIRES (NO PROBLEM FOUND). THE VIBRATION AND NOISE DID NOT ABATE EVEN WHILE SLOWING DOWN TO GET OFF FREEWAY. NOISE AND VIBRATION DISAPPEARED AFTER GETTING BACK ON FREEWAY. 5/15/1999:WHILE DRIVING THROUGH A RESIDENTIAL AREA, EXPERIENCED VIBRATION FROM FRONTEND AGAIN WHILE BRAKING. AFTER STOPPING AT A STOP SIGN, THE SOUND/VIBRATION WENT AWAY. 5/17/1999:RETURNED CAR TO DEALER-ASKED THEM TO CHECK THE BRAKES AND TIRES AGAIN. I INFORMED THEM OF THE PROBLEMS, BUT DEALER COULD NOT DUPLICATE. TIRES WERE BALANCED. 6/5/1999:I GOT OFF 605 FREEWAY AT FIRESTONE EXIT AND PROCEEDED EAST. I WAS GOING TO MAKE A RIGHT TURN ON HOXIE AND WAS IN THE RIGHT HAND LANE. THE TRUCK IN FRONT OF ME STOPPED SUDDENLY. I STEPPED ON THE BRAKES BUT MY CAR DID NOT STOP AND CONTINUED TO ROLL (I WAS ROLLING FORWARD AT APPROXMATELY 5MPH AT THE TIME). I STOPPED AFTER HITTING THE TRAILER HITCH OF THE TRUCK IN FRONT OF ME. THE TIME WAS 11:45 AM AND THE ROAD WAS DRY. IT FELT LIKE THE BRAKES NEVER ENGAGED. THE DRIVER OF THE TRUCK CHECKED HIS VEHICLE, BUT FOUND NO DAMAGE. HE DID NOT SPEAK ENGLISH AND SHOOK HIS HEAD WHEN I SHOWED HIM MY LICENSE AND INSURANCE CARD. 6/7/1999: REPORTED ACCIDENT TO MY INSURANCE AGENT. I TOLD HER THAT I WOULD BE TAKING THE CAR TO A BODY SHOP FOR ESTIMATES AND ALSO TO THE DEALER TO FIND OUT WHAT WAS WRONG WITH THE BRAKES. 6/10/1999: TOOK CAR TO LEXUS DEALER. DEALER FOUND LOOSE CONNECTION AT HYDRAULIC ELECTRICAL CONNECTOR AT BRAKE BOOSTER VALVE BODY. DEALER STATED THAT MFG. DECLINED TO WARRANTY BUMPER DAMAGE. STEERING WHEEL STILL VIBRATES.