brake issues - pedal slowly drops to floor - abs pump concerns

Hello everyone, I am having some issues with my 2015 Expedition with braking. I went from a 2010 Navigator (which braked very well) back in May to this 15 Expedition. I noticed right away that something felt different about the brakes. I started out by changing the front pads and rotors (had shaking feel when stopping). This didnt help the problem. I really didn't notice the pedal issue until I got out the travel trailer and was transporting it. The pedal would drop when coming to a stop sign. I bled the brakes with no positive results. I purchased a new master cylinder from Ford. Pedal felt slightly more firm but still had an occasional pedal drop. After researching more, I felt it was the ABS pump. I purchased a used one off a 15 Expedition that had 80k miles. This is where things went south. After installing the new pump, I used forscan to run the pump, draining to each wheels. Then I had my girlfriend pump the pedal as I bled each wheel, in proper sequence. When I was done with this, the pedal felt very firm. Before, the pedal would slowly drop (engine off) when pressing on the pedal. So I went for a test drive and the minute I started up the vehicle, my pedal went soft a bit. I backed out of the driveway and then into Drive. I drove approximately 15 feet and then my dash lit up like a Christmas tree. I was getting Service Advance Trac, Incline (or something similar) and a couple other messages. My brake light and ABS light were on. I backed up and pulled in driveway, shut car off and then back on. Everything was fine until I backed out and went forward. So I thought, maybe its the module. Oh.. and the pump I bought came with a different module. I installed the new pump with my module. I swapped out the module but this time everything lit up at the time of engine start. Forscan brought up the VIN issue with the module, which is what I expected. I swapped out the module to my old one and the issues went back to where the lights come on when pulling away from the garage on street.

I am at a loss... I will be swapping out the ABS pump and using my module.

Any thoughts? I feel as if either, A: the pump I bought is bad. B: the pump I bought is not compatible with the 15 Expedition. I am hoping (praying) that my issues go away with my original pump.

I swapped back to my ABS pump & module and everything above was corrected, except for the pedal drop. Last night I swapped in a different ABS pump along with ABS module and everything as described above came back. Pedal situation was not corrected. Can anyone confirm if the pump needs to be reprogrammed at the dealer or is it just the module? I am at a loss as to what my situation could be caused from. The only thing that I have not touched is the brake booster. I really hate chasing parts around but this is the last piece. I am to the point where I feel that I might need to take it to the dealership but would honestly like to avoid it if possible.

jruppert said:

I am to the point where I feel that I might need to take it to the dealership but would honestly like to avoid it if possible.

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There is one braking system that has tabs on the brake pads and if you put pads on without the tabs it makes the brakes squishy. There is a thread on this subject.
Here is the thread start with post #82 for the info on the tabbed pads.

https://www.expeditionforum.com/thr...brake-pedal-sinking-to-floor-now.44648/page-9

Shortly after purchasing the expedition, I replaced the pads up front because I noticed a lack of braking. I installed the pads properly. I do not recall how they were when I pulled apart. But my situation is not that I have squishy brakes but that my pedal sinks to the floor.

jruppert said:

not that I have squishy brakes but that my pedal sinks to the floor.

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Squishy was a word i used. My petal sinks to the floor is in the name of the thread i suggested.
@UniqueTII in that thread (after replacing everything) found the problem to be incorrect pads.
Thier expy is a 2015 also.

I have to admit, reading your post made me think.. why in the heck would pads cause this issue??? Then I read the post and realized he used Powerstop pads and rotors. My sinking pedal issue started after upgrading to Powerstop. The vehicle did not brake well and I had the same issue with the half contact mark on the original rotors. Anyway, I will try replacing the pads to start with. Thanks for pointing me in this direction. I cannot believe pads would cause this issue. It doesn't even make sense. But... it seemed to cause him problems. So....

I am a little skeptical on the pads being the problem but I have to go with what they guy did. I ordered some pads. I'll update once I change them out.

I just purchased a 2017 Expedition EL Limited and noticed a mushy brake pedal and a weak stop when I was test driving it. I looked into this and there was a TSB recall for this exact issue due to the brake master cylinder leaking and sometimes into the brake booster. The dealership replaced theses before I would agree to purchasing. This did make a difference.

I've replaced the pads, front calipers (driver side had torn seal), and replaced check valve for booster. Still no improvement. It sorta feels like a clutch pedal instead of a brake pedal.