Steering issue

I have a 95 Crown Vic, and when I make a hard left the steering feels like I lose power steering. It is super hard to turn, I'm not hearing any noise and I can see the power steering fluid whirling around in the reservoir. I don't lose any voltage or anything. I have replaced the power steering gearbox, right side tie rod, and upper and lower balljoints on both sides, all within the past few months. Any ideas? Help please.

Short and simple

check the last thing you did..... and who ever said that new parts are always good?

I had a similar problem on my 97 interceptor..try spraying the knuckle in the steering shaft..I have had to do this twice and it works fine after..spray with wd40 or pb blaster..cheap quick fix if it works..