Power steering works normally to one side, but hard to the other

It's possible when he repaired it he didn't Jack it up and adjust a steering that's so you got right and left equal pressure possible one way and not the other you check the steering nut on the steering box to make sure it's a it's right if your steering column Center when your wheels are straight

Take it back and have them check it out. Maybe the inner seal is leaking on that side of the rack, slightly, causing pressure loss. It seems odd that it would not be hard to turn in both directions, however the other possibility is that if the steering rack has worn teeth. This will effect a portion of the steering (that has the bad teeth), but not all of it.. Strange..

If you didn't want to run back to your specialist just yet, check the power steering fluid resivour, use only approved FoMoCo fluid, and top off a low level as you rotate your steering wheel from hard left to hard right, at idle.