Ultimately, the X-bodies — which included the 1980–1985 Chevrolet Citation, 1980–1984 Oldsmobile Omega, 1980–1984 Pontiac Phoenix and 1980–1985 Buick Skylark — became synonymous with their design defects, and GM's mishandled response.

At a time the company had begun reorganizing, and began using a new engineering approach, with its divisions responsible for a single aspect of the design rather than an integrated whole.

Automotive journalists and reviewers noted in the autumn of 1979 rear wheels' tendency to lock upon heavy braking, such as in an emergency situation, a potentially dangerous behavior compromising vehicle control.

In the first year of manufacture, hundreds of complaints noted rear brake locking, with dozens of related accidents and injuries — including one death, the latter triggering a lawsuit.

GM issued a voluntary, though unpublicized recall to modify the brake proportioning valve of only the earliest manual transmission models, less than 50,000 of the already more than one million X cars on the road.