1995 4runner brake pedal pushing back.

[CMiles]

I have a 1995 4runner 3vze 210k miles about 6 months ago the brake booster went out and right before it did the brake pedal started pushing back then just completely stopped having power brakes. I replaced it and didnt have either issue until about two weeks ago the pedal started pushing back. So I decided to warranty replace the booster before it went out completely again. I replaced it and I am still having the pedal push back... the pedal goes pretty much to the floor then seems like it gets pressure in the booster and pushes back at you causing the brakes to apply rapidly.

What would cause the pedal to push back like this?
I thought maybe the hose had a leak but cant seem to find one.

 

[KidVermicious]

Wobbly caliper?

 

[CMiles]

Wobbly caliper?

Everything seems tight... I have a slight warp in one rotor but you can only feel it slightly at highway speed under heavy braking.

 

[drychlik1]

I have a theory that when you initially press the pedal the vacuum is building in the booster, but your master cylinder could have a pitted cylinder causing slow application of the brakes. as it then applies the brakes, you get the pedal "push-back."

But, my first thought would be to cap the vacuum line to the booster and try it to see if it changes. If not then you have eliminated a vacuum leak.