What NHTSA says the defect is
A RETURN FLUID LINE OF THE FRONT BRAKE SYSTEM IS MISCONNECTED TO A REAR BRAKE FLUID RETURN. WHEN THE ABS SYSTEM COMES INTO USE, ALL THE FLUID FROM THE FRONT BRAKES GOES TO THE REAR BRAKE SYSTEM. THE FLUID RETURNS TO THE FRONT SYSTEM WHEN THE BRAKE PEDAL IS RELEASED.
The risk NHTSA states
TOTAL LOSS OF FLUID IN THE FRONT BRAKE SYSTEM LEADS TOINCREASED STOPPING DISTANCES, AND COULD RESULT IN VEHICLE COLLISION.
The remedy NHTSA states
REPLACE DEFECTIVE ABS SYSTEMS.
Campaign 91V079000 · reported to NHTSA 13 May 1991 · Read it on nhtsa.gov →