Happy to report - fix to ABS module worked indeed! Really happy about that, no lights and module communicates in Techstream.
Replaced and installed correct brake line with correct clamp(s)
Replaced MC, all proper hardware.
Speaking of hardware... Common theme through the truck - 13mm hardware. I think I removed all of it by now, maybe this is what causing all this lack of luck stuff
I mean, 3 12mm and 1 13mm nut on MC cylinder. I didn't notice, and it drove me crazy for 5 minutes trying to get my socket on and work it under there

)
Parking brakes R&R - all works great.
MC works great. Brakes are good, I think better then before.
View attachment 3683461View attachment 3683462View attachment 3683464View attachment 3683465