Hey, I am in the final stages of removing my heater core. I am trying to disconnect the ac and it wont come losse! What am I doing wrong!?!? I have an ac disconnect tool, and I can disconnect the liquid line from at the front of the car no problem. But at the firewall where it connects I CANNOT get it loose. I am tugging on it from inside the car and out, the tool seems to be in but its not coming off! Please help.