After all this time and money the mechanic is telling you that the rack you ordered is bad and he will not warranty the labor cost. So now it is time call and scream at the company who sold the rack. But hold on...is there really issue tor more did the new rack that has exposed a preexisting issue. Many times an old power steering rack is loose and very easy to move, this means very little force is needed from the power steering pump. When the old worn out pump is now coupled with the new rack means that it may not make enough pressure to turn the rack. A tight rack can seem like a binding rack but it will never bind in both directions. An easy way to check for a failing pump is to rev up the motor and see if the car turns easier...if it does, you have a bad pump.
Mechanics don't care about diagnosing the issue most of the time if you bring your own parts but they are happy to charge labor again and again. Be sure that the company who is installing the part knows what they are doing and that they are good people. Every company can smile at you and act like a friend...walk onto a used car lot and you will have a new best friend till you buy a car but its all an act. Make sure the repairs to the steering system are done by a trust worthy company that can determine real issues for you.
