Brake Master Cylinder problems of the 1997 GEO Tracker

While driving on interstate highway, it felt like my transmission had went the car would not move further after going through a toll both. Had car towed to nh chevy car dealer, found nothing wrong on 3 occasions. Personal NY chevy dealer found master brake cylinder had blown causing brakes to lock on their own, while also causing brakes to severely smoke. Took over 2 weeks to find problem & correct.