power steering issue.. binding!! help

[racinmasonc]

My 05 legacy gt when it's cold or warm when turning the wheel it "binds" up and it takes a lot of force to turn the wheel. At idle sitting at a stop or taking a sharper turn at speed.. almost hit a car on the other side of the street because I couldn't turn the wheel. What could be causing this? Has new ps pump, new rack and pinion.. I did notice the ps belt is in rough shape, cracking and missing part of 1 rib but it's tight and it's not squeeling. Possible it's a silent slip causing the this?