NHTSA Complaint #11286510 — 1991 CHEVROLET ASTRO

BEGINNING ABOUT A YEAR AGO, HAVE HAD INTERMITTENT HARD PEDAL WHEN BRAKING. OCCURS RARELY, WITHOUT WARNING. NO ABS LIGHT SEEN BUT SUSPECT POSSIBLE ABS MALFUNCTION. PEDAL DOES NOT PULSATE BUT A FAINT GROWLING, GRINDING, OR BUZZING NOISE IS HEARD. MAY BE ABS MOTOR CYCLING. DURING FAILURE BRAKES ARE BARELY OPERATIVE. USUALLY RETURNS TO NORMAL OPERATION AFTER 2-3 PEDAL PRESSES. SOMETIMES PULLS SHARPLY LEFT, OCCASIONALLY RIGHT, ON BRAKE APPLICATION. THERE IS NO LOSS OF POWER STEERING. OCCURS MOST OFTEN AT FREEWAY SPEED BUT HAS ALSO OCCURRED AT SLOWER SPEEDS. HAS OCCURRED BOTH IN SUDDEN, HARD BRAKING AND IN VERY LIGHT USE. HAVE HAD ALL POWER COMPONENTS, ALL RUBBER HOSES, POWER STEERING PUMP, AND BOTH FRONT WHEEL BRAKE COMPONENTS PROFESSIONALLY REPLACED. VEHICLE HAS FRONT DISC/REAR DRUM AND HYDROBOOST. MECHANIC USUALLY CANNOT DUPLICATE THE PROBLEM BUT HAS DONE SO ONCE AND HAS NO EXPLANATION FOR IT. SEEKING TO LEARN POSSIBLE REASONS AND CURE.