The mechanic used a little amount of loosening agent and manipulated the rod many times. This sensation is pleasant; the pressure appears adequate, as though the diaphragm is functioning properly. I will reattach this. The issue persists. At this juncture, it was seen that air was being inhaled through the breather tube. Recede the servo.
Upon exerting pressure on the brake pedal, it first exhibits significant resistance; but, with additional force, the pedal rapidly descends to the floor, resulting in an emergency stop of the car. Depending on the pedal's mood, it may gradually return to the top position and disengage the brakes; however, in most instances, the pedal must be manually lifted back up to release the brakes.
I have replaced the master cylinder and the wheel brake cylinders.