I know its grasping at straws, but did you check the vacuum tree to make sure it is free of any cracks?From the tree labeled BB
I thought that too but it must be the booster since the MC can be unbolted and my brake pedal still won't return.
Good thought here.... The bushings in the pedal assembly could be worn out...Binding in the pedal/ pedal assembly?
With the pedal bound, can you unclip the booster rod from the pedal and see what is free? Pedal or booster?
I'm suspicious that you've gotten multiple boosters in a row with the same issue. Needs to be something that has remained with the car after changing all the parts that you have.
Might be worth double checking that......... Pushrod is adjustable, and is adjusted......
Previously....Good thought here.... The bushings in the pedal assembly could be worn out...
Just checked. No bushings.