Toyota said Wednesday it will recall nearly 780,000 vehicles in the United States to fix a defect that could allow rust to form in the suspension to the point where parts break off. "Toyota has determined that if the nuts on the rear suspension arm are not tightened following the proper procedure and torque specification during a rear wheel alignment service, excessive play may occur at the threaded portion of the arm, followed by rust formation," Toyota said in a statement. "If this were to occur, the threaded portion of the rear suspension arm may wear and cause the arm to separate." The recall comes a month after Toyota added two models to a controversial 2009 recall launched after floor mats became trapped under the accelerator and were linked to dozens of deaths. Toyota's mishandling of the initial problem and other reports of sudden, unintended acceleration led to the recall of more than 12 million vehicles worldwide, a US congressional probe, more than $50 million in fines from US regulators and public apologies by its chief. Toyota has worked hard since then to regain its once-stellar reputation for safety, even as the Japanese giant faced the impact of the economic crisis, a strong yen and the devastating 2011 quake and tsunami which shattered supply lines. Toyota managed to regain its position as the world's number one automaker in the first quarter of 2012, stealing back the lead from US giant General Motors. Wednesday's recall affects 760,000 Toyota RAV4 sport utility vehicles from model years 2006 to 2011 and 18,000 Lexus HS 250h vehicles from the 2010 model year. Toyota said it has not yet devised a remedy, but will contact owners and offer repairs free of charge as soon as it has.