If you changed your master cylinder at any point, make sure the rod from the brake pedal into the master cylinder is adjusted correctly. if it is too short, no or soft brakes. the rod may look like it is not adjustable, but it is two parts screwed together. On one occasion, i had to take the rod and clamp it in a vise while turning the other end. Looking at the rod it appeared to be one solid piece. It was very difficult to see where the two parts were screwed together.