A Montgomery County judge has turned down a former Philadelphia garage owner’s request to withdraw his guilty plea in a fatal crash on the Schuylkill Expressway. 62-year-old mechanic Joseph Jadczak admitted his role in causing a man’s death by allowing an unsafe tractor-trailer on the road. He provided inspection stickers without having looked at the truck, and he pleaded guilty to vehicular homicide. His new lawyer says he pleaded guilty because he was scared, his previous lawyer failed to give his client the advice he needed, and Jadczak probably would have been acquitted if the case had gone to a jury because his role in the crash was remote. Truck owner Victor Kalinitchii and driver Valerijs Belovs pleaded guilty to similar charges late last year. The truck plowed into four other vehicles during a traffic jam on the Schuylkill Expressway’s Conshohocken Curve early last year, killing 49-year-old David Schreffler of Fort Washington. Pennsylvania State Police and Montgomery County Detectives found that the tractor-trailer could not stop because it had bad brakes.