Ok. Look to start, I differ from the Foros friends, the one you send it to fix it does not guarantee that they do the chamba well, sometimes you have to do it, what if it guarantees you is that they will take out the wool, with respect to the fault it still is not clear to me if they are the rear or the front, if they are the rear what is happening is that the distributor valve is stuck the liquid that comes from the pump to the left or right wheel and regulates the precion so that the wheels are not tied; Well, if they are the front you have to check if your cylinders or leagues are, you can do this when the tires are tied, it loosen a pothogue and if the liquid comes out and the tire is released then you have to maintain the cylinders, that is why it is revealed to change the entire brake fluid periodically and not when a failure appears. I do not think it is your pump, since when the pump fails "loses precion" and the brake pedal goes to the bottom.