Is it the rack or the pump?

[Ian Lyn]

When it is cold.like it has been all month here in NY, the steering is hard
and binds very badly the first 10 minutes of driving. Then when I drive for
a while it loosens up. But it binds when you lock it extremely to either
end. If I try to simulate autocross maneuvers it feels numb and feels like I
lose power in the steering. I noticed the pulley stop when I try to lock it.
There is a rebuilt rack on the car. What do you think?