'91 S-10 Blazer - 4.3L - 4 wheel drive - NO ABS (came stock with ABS)

So... Just replaced the rotors and pads up front. Wheel cylinders and shoes are less than 6 months old, with less than 3000 miles on them. Removed ABS (Didn't work, didn't want to try and figure out what was wrong with it). New lines for the front. Full brake siphon with new brake fluid then bled them properly.

Symptoms : Brake pedal is low, goes almost to the floor when stopping (about 1/2" from bottom throw). Brake pedal stays firm with engine off (good master cylinder?), drops properly when starting (good vacuum?), albeit drops low.

No fluid leaks at cylinders/calipers.

I'm honestly starting to suspect the Vacuum Booster, but I don't want to just go and drop $150 for a new booster, if that's not going to fix it.

EDIT : ABS Removed 'cause 1. It never worked when I got the truck. 2. I thought maybe it had air in the line and was causing these issues. Removing the ABS system didn't change a thing. Same issues.

 

theres probably air in the system somewhere. i dont know how it ends up getting in there but ive done jobs where i clamp the lines off doing front calipers and somehow air get sucked into the back. try bleeding everything again, all 4 tires, master cylinder etc and probably get lucky.

booster shouldnt make pedal go low unless something mechanical broke inside of it. if the vacuum dies off in it it will just be harder to brake

 

Re bled today, still dropping real low, and is soft. I did find out I over torqued my caliper pins and shredded the threads. That's fixed. Still soft brake pedal.