Radiator hose replacement help plz
 

http://img221.imageshack.us/img221/5...3072fr5.th.jpg
This is of a 1993 Z28 LT-1 The picture'd hose runs out from the the water pump to the firewall i think the heater im not sure. The yellow box indicates where the two hose's join i only need the hose that connects to the pump how do i disengage the hose from the black piece in the picture.