Breaks not engaging after new parts instalation

How is the brake pedal, high and firm or low and mushy? By locking up, do you mean skidding the tires under light pedal application or the brakes would start to apply themselves while driving?

Pedal is low and mushy. And once the pedal was pressed, the one would not disengage.

Given the multiple symptoms and series of events, is it possible the brake fluid has been contaminated with a petroleum product? Check the rubber bladder seal under the reservoir cap to see if it's blown up and mushy. If it is, everything with rubber parts that contact the fluid must be replaced and the steel lines must be flushed and dried.