In he returned to Formula One full-time with the returning Brabham team who would be running the Judd V8 engine. But while the former champions were initially competitive, with Brundle running third at Monaco until a flat battery forced him to pit for a replacement while his teammate Stefano Modena finishing third, Brabham were unable to recapture their early past success and Brundle, who had failed to pre-qualify for both the Canadian and French races during the season opted to move back into the sports car arena for 1990. His 1990 24 Hours of Le Mans victory rejuvenated his career, but still a top-line race seat in Formula One eluded him. As well as contesting races in sports prototypes, Brundle also contested the American IROC series in 1990. He took victory at the temporary circuit at Burke Lakefront Airport (the only IROC victory for a British driver) and finished third in the overall standings. In 1991 he rejoined Brabham, but the squad had fallen even further down the grid and good results were sparse.