I Just Replaced My Rear Calipers And Pads

And When The Guys Went To Bleed The Brakes

They Wouldn't Bleed.

And Now My Car Stops But

,when I Press The Pedal,

It Hesitates Like Its Tight

But Then It Goes To Floor.

What Is That Probelm

Please Help

How Can I Be Sure If It's The Master Cylinder Or Not

Thanx Fam