Hydraulic pressure in power steering systems is huge and will overcome all but the worst mechanical failures.
I post this as a cautionary tale....
Recent a friend was having issues with leaking power steering fittings on the PS rack head. It had been apart multiple times replacing O rings, looking for damage etc when the decision was made to replace the factory lines with aftermarket ones utilizing AN fittings (you know where this is going right?). So anyway everything was assembled, filled with fluid and bled but when he tried to turn the steering wheel nothing happened. The checked for leaks etc and tried it again turning the steering further and further until they heard a "bang" at which point the engine was shut down and they checked under the car where they found a large puddle of PS fluid.
They put the car up on the lift again to have a look underneath when they discovered the the whole head casting of the power steering rack had come away from the body. It had snapped off the 2 cap screws that hold the casting onto the rack. The cause? He had mixed up the feed and return lines on the rack because they were both -6an fittings!
Never under estimate the power of hydraulic systems!
Fortunately the repair was simple, 2 new bolts, no damage to the threads in the rack itself.