2000 XLT hybrid. The brakes have always been soft since 2019. One day I checked and the master brake cylinder was leaking. So I replaced it with a Motorcraft. One time I had to mash on brakes hard and it started leaking again. I bought a Duralast replacement and put in it. Not long after it was leaking. I replaced both brake booster and master brake cylinder. Same result. Took it to mechanic. Replaced master brake cylinder. Bled it well with compressor on fluid cap. Used scan tool to bleed modulator. Also adjusted the booster this time. Pedal still soft. Works but not as it should. I don't think there is much more to do except to maybe replace pads or shows. Brakes don't squeak. But there are times I hit the brake and it feels like the truck isn't going to stop. So its ot as it should be. Maybe I should have taken it to the dealer instead of paying $200 (which is cheaper) and having the same result as when I did it myself. But my parts are under lifetime warranty and the dealer will want to install expensive Motorcraft. Could use some ideas.
Mechanic said that he thinks my pads or shoes or hardware kit needs replacing. He said everything is engaging.

 

Do you have 4 wheel ABS or Rear wheel ABS?

Either needs to be bled using an electronic hand held device plugged into the vehicle, it open the ABS valves so you can bled any air out

Soft pedal means air in the system OR a failed Rubber Brake line, flex lines at each from wheel and one above rear axle
If these break internally they allow the brake fluid to expand the outer cover, so absorb brake fluid pressure and make pedal feel soft

Brake system is pretty simple
It has 0 pressure in the brake lines when foot is off the pedal
As you apply brakes the Master piston it push forward which pushes out brake fluid in to the front and rear brake lines
Because its a fluid it can't be compressed easily so that fluid pressure is transferred to all the brake lines equally, closer or farther away doesn't matter, pressure is equal at all 4 wheels
If there is ANY air anywhere in the system then it compresses under the pressure and that drops the pressure in the whole system, the soft "feel"
OR
If any brake line can expand then that also absorbs the pressure in the whole system, soft pedal

Vehicle brake systems also have a proportioning valve, can be in the Master or a separate valve, in a car/suv its a 60/40 valve, 60% of the pressure is sent to front brakes, 40% to rear to help prevent rear brake lockup because rear of vehicle is lighter
Pickup trucks used 70/30 proportioning because rear can be very light compared to front
But not your problem

ABS systems use valves and passages to help prevent wheel lock up, these can get air trapped inside, so could be your problem