Here's the story & what has been done. 2 front caliper & one rear replaced last year. Replace remaining driver side a month ago. Goofy bleeder screw on bottom of this caliper I thought was causing soft pedal. Anyway, power bled all calipers and have a good pedal with the truck off. Can hardly move it so I know there's no air left in the system.

Check master & see that its leaked down the face of the brake booster. Bench bleed the new master properly, change it out & bleed brakes again. Same good pedal with truck off. WTH? Noticed on the booster rust at the bottom where the m/c was leaking. Figuring brake booster bad. Could see & hear air escaping where the push rod goes through the firewall from inside the cabin. Changed out the booster. Still good pedal with truck off.

Now I know the pedal will drop when the truck is started but can't get a good pedal as long as the truck is running. Checked the vacuum hose to the booster & vacuum seems to be good. Actually did this before changing the booster.

Before & during this whole process I've got ABS light on the dash. VSS sensor had been replaced abt a year & half ago. Was gonna clean it but couldn't get the darn bolt out. 10mm correct? Gonna hit it with some freeze off & give it a go when I get the time.

I know the abs is good as its been operational this winter a few time. Where is the abs control module? On my expedition I had a bad one that would activate any time the brakes were applied. Disconnected and all was good as far as regular brakes.

I looked at the front sensors & the pass side may be questionable. The wire looks brittle & wires going into the connection(vehicle side) appear to be somewhat twisted & exposed.

I'd think I should have good pedal feel anyway. Thinking of changing out the vacuum hose just to see if that helps.

I know I've jumped around but if I'm typing out of frustration. So if anyone can decipher this post & help me figure it out I'm all ears.