Re: power steering issues
I have worked on power steering systems, but only to replace failed parts. I have worked on industrial hydraulic systems, which is what a power steering system is, so somebody may need to step up to the plate and apply some guidance here, but I'm going to talk generalities about hydraulic systems and someone may need to translate over to automotive.
In a hydraulic system, there's generally something engineered in to limit how long pressure can be applied to move something. Sometimes it's a limit switch to a solenoid, but most of the time it's an internal bypass, much like a relief valve, that regulates and ports the high pressure side to the low pressure side (the return). I've always made the assumption that the noise you hear when you've turned your wheel to it's limit was the bypass porting the excess pressure back to the return. I've also always assumed that it was located internal to the pump, but if you've changed the pump, it sounds like it might be located in the rack. With out grabbing a wrench and poking it with a stick, you've reached the limit of my knowledge of the system.
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