Power assist: vacuumRecall 77V-119 · Chevrolet and GMC vehicles
GENERAL MOTORS CORP. recall 77V-119 covers 1,232 Chevrolet and GMC vehicles for a power assist: vacuum problem, reported to NHTSA on August 10, 1977.
Source: NHTSA recall 77V119000 and manufacturer quarterly reports. Started by the manufacturer.
The problem
ON THE INVOLVED VEHICLES, THE NUTS WHICH ATTACH THE BRAKE MASTER CYLINDER TO THE HYDRO-BOOST UNIT MAY HAVE BEEN OVER-TIGHTENED. THIS COULD HAVE CAUSED STRIPPED THREADS AND CRACKED ATTACHING FLANGES. SHOULD THESE NUTS FAIL, THE PARTS MAY SEPARATE AND LOSS OF SERVICE BRAKES WOULD RESULT.
The fix
DEALER WILL INSPECT FOR CRACKS IN THE ATTACHING FLANGES; UNITS WITH CRACKS PRESENT WILL BE REPLACED. IF NO CRACKS ARE FOUND, THE STUDS WILL BE REMOVED AND THE HOLES DRILLED OUT. THE UNIT WILL BE REASSEMBLED USING BOLTS AND NUTS IN PLACE OF THE EXISTING STUDS.
VEHICLE DESCRIPTION: LIGHT TRUCKS.SYSTEM: SERVICE BRAKES; MASTER CYLINDER TO HYDRO-BOOST UNIT ATTACHING NUTS.CONSEQUENCES OF DEFECT: LOSS OF BRAKING CAPABILITY COULD OCCUR WITHOUT PRIORWARNING AND COULD CAUSE LOSS OF VEHICLE CONTROL AND AN ACCIDENT.
Recall repairs are free. Confirm whether this recall is open on your vehicle by entering its VIN at nhtsa.gov/recalls.