Assuming there is fluid in the reservoir , a good place to start is the front wheel that was dragging, only reason they drag is if the extended slave cylinder fails to return fluid and the shoes stay extended pull the brake drum, cinch a thin cargo strap around the shoes , tight, loosen the bleed screw on the slave cylinder and have some some one pump your brakes down , hold tighten bleeder, pedal up . loosen the bleeder, pedal down, repeat, ensure you keep fluid (dot 5 ) in master cylinder, repeat until you get fliud ( slave cylinder is likely bad) . rubber flex hoses are likely originaly , they sometimes collapse check each wheel