1999 Ford F-150 ABS Pulsation

Hello and thank you for your time. I own a 99 F150 with 182k on it. I recently had an issue with a ABS pulsation in the pedal at the end of the stop (below 10 mph). ABS light was on so I hooked up scanner and ran codes ended up changing RF Hub bearing and ABS exciter ring on RF and on the rearend. At this time the pedal goes all the way to the floor. But truck does eventually stop. So I check and changed front rotors, Both Calipers in front, pads hardware, rear pads and machines rotors. I line locked all brakes lines and pedal still dropped to floor. So I changed master cynlinder as well. Now truck brakes are fine until below 15 mph. The ABS light does not come on whatsoever. When pedal pulsates and drops to floor but truck still stops. I am looking for the reason and cure to get pedal back to normal.