The prior own said this has been a problem since new. I've had it for a while now and its worse. All new pads, rotors, and brake fluid. Sometimes the pedal is firm, others not. In either case the brakes just don't grab. Stopped with foot hard on pedal, and the pedal gradually goes to floor.

Tried those little booster, start engine, stop engine tests, and they all seem normal. Tried spraying starting fluid to see if vacuum leak, and negative. Went to junk yard and they want $30 for a booster, and $5o for a abs pump module, but what if the origional ford part was bad on all vans and I'm paying with money and time and it still doesn't work?

Those modules for different years (2004, 2006) have different part numbers at the junk yard than my 2005.

Soooo, Pedal firm somtimes, soft others, but always slowly fades, and never grabs even if you stand full force on pedal. It's not a bleeding, pad, or fluid problem. What do I change first? that ABS module pump? ($50 for a ten year old part) will a 2006 one work?

 

Your front rubber brake hoses could be tired. They can cause your braking symptoms. I replaced the ones on my 2004 Freestar in 2014 due to soft braking. That cured my problem (But may not be yours). Who changed the brake fluid? Was it a full replacement thru the system until the fluid ran clean thru all 4 calipers? Since your pedal slowly sinks to the floor with pressure, it's possible that your master cylinder is bad.