A Los Angeles federal judge rejected a defense motion to throw out more than 200 pounds of high-quality cocaine seized as evidence against a Laguna Hills man, who was arrested Dec. 6 during what authorities said the largest seizure of drugs in Orange County history. In his ruling, U.S. District Judge Stephen V. Wilson held that authorities had probable cause to stop a van driven by Daniel Serrano, 39, on Muirlands Boulevard in the Lake Forest area. Serrano had been under police surveillance for two months for alleged cocaine involvement. However, the judge chastised authorities for continually suggesting to Serrano, a former supervisor for Xerox Corp., that he should drop Los Angeles lawyer Mitchell W. Egers as his defense attorney. Such suggestions were improper, the judge said, but were insufficient grounds to suppress the cocaine as evidence against Serrano. Serrano was indicted Dec. 17 on one count of possession of cocaine.