Ford Repair: Brake pedal fade, 1998 ford windstar, ford windstar

Question
Hello,
The vehicle is a 1998 Ford Windstar 3.8L.

The ABS codes I acquired with a near new and up to date Snap on scanner that a friend owns. He told me the codes, now I am trying to figure out this last code. Two others were for an ABS sensor in the rear, easypeezie.

I bought this van and everything started to fail once I got it home. The brake lines rotted near the rear so I replaced both sides up to the front junction ports just under the front driverside firewall. Brakes were replaced/good all around, same for wheel cylinders, hardware, caliper sliders. I bled and bled and it wasn't quite right, I kept getting a good initial pedal, but quickly brake pedal fade to the floor. Once nearing the floor, the ABS motor kicked on (due to the ABS sensor I need to replace). Pumping helps me stop fine, but any sustained hold on the pedal, it will go right down to the floor. I replaced the master cylinder with new/rebuilt, had to put on reservoir according to instructions. Filled, bench bled and rebled the entire system many times from front to back with a vacuum hand pump, assistant on the brake pedal and a one man bleeder container. Still the same. Manual said some need to be factory bled, i.e. scanner. My friend was kind enough to scan it and activate the ABS motor. I noticed a slight improvement, brought it home and rebled the system again. No change. The codes were C1168, C1235 and C1140, then he erased them. The first two are easy, the last had a list of things like EHCU, junction block or module. I'm not losing any fluid, the master cylinder remains full. Before I go replacing more undetermined parts, I'd like to get an educated opinion on what to check next. Possibly a brake booster or faulty rebuilt master cylinder, I've had many parts fail right out of the store box. It's been a long time working on this and I have exhausted all possiblities I can think of.

Thanks for helping.

Answer
first buy some plugs and remove brake lines from master cylinder and install plugs pedal now should be hard as a rock if not you definitely have a bad master cyl. if it is now remove a plug install a line see if you have a good pedal if not try bleed the brakes in that line and look for improvement do this with each line-where did you get your hydraulic parts three different times i have worked my tail off because of bad wheel cylinders believe it or not-more than that on master cylinders-i only by name brand now-wagner/bendix/or factory. also the quality of brakes here again i only use good brand and have no patience anymore diagnosing cheap parts. so if you bought them from az or store brand parts do yourself a favor and start over.

good luck