The problem revolved around salt water splashing off the WRX STI’s brake lines through a gap in the Subaru’s fuel tank protector. The salt would eat at and corrode the brake lines, which were reported to leak brake fluid. When the brake fluid would leak, this could increase the amount of time and distance a driver would need to stop the vehicle. Unbeknownst to the driver, the brake line corrosion posed a serious crash risk.
To fix the issue, Subaru dealers applied an anti-corrosion wax to the brake line’s four-way joint connector, free of charge. The Subaru WRX STI hasn’t had a recall since this 2014 issue.