NHTSA (USA)Critical
1991 MAZDA NAVAJONHTSA Campaign #96V024002
The official notice
Defect
THE STUDS WHICH ATTACH THE BRAKE MASTER CYLINDER TO THE POWER BRAKE VACUUM BOOSTER ASSEMBLY CAN DEVELOP STRESS CORROSION CRACKING AFTER BEING OPERATED FOR AN EXTENDED PERIOD OF TIME IN THE SOUTHERN CALIFORNIA LOCATION.
Safety Risk
IF A CRACK OCCURS, IT COULD RESULT IN ONE OR BOTH STUDS FRACTURING. THE MASTER CYLINDER COULD THEN SEPARATE FROM THE VACUUM BOOSTER, WHEN THE BRAKES ARE APPLIED, PREVENTING THE SERVICE BRAKES FROM FULLY ACTIVATING INCREASING THE RISK OF A VEHICLE ACCIDENT.
Remedy
DEALERS WILL REPLACE THE POWER BRAKE VACUUM BOOSTER ASSEMBLY.
Updated June 10, 2026