It's been a while, but they still call it a Newtonian fluid. Couldn't have changed that much right?

If you were to loop the ports on the rack, it would allow fluid to move from one side of the piston to the other.

In this case, any rack movement would move the piston and create a pressure differential. The piston does work on the hydraulic fluid, forcing it into the lines through a small orifice. Basically a valved damper. The pressure differential also acts like a spring to counteract the movemement of the piston. That energy has to come from somewhere, thus lessening the severity of an 'impact load'.

With slower or sustained loads, the pressure would equalize on both sides of the piston with little noticeable.

I guess I should qualify my statement. It COULD happen depending on the sizing of the rack and power steering lines, condition of the piston, how much air is in the system, etc... Personally I think it does, but haven't done the math on it. And won't. It's probably more of an incidental effect of hydraulic systems than a calculated design feature.

 

did you swap in the manual rack mounts? If your not using the manual rack mounts the rack will have some play in relation to the subframe

 

^this. seems simple but the mounts are different between the racks. maybe this was overlooked?

I have an 86 manual rack and I prefer it to the power rack. ya, I wish the ratio was a little faster but its not so bad unless parallel parking and even then, it's manageable. I drove my brothers s5 with power steering for a while and like my car a lot more. manual lets me feel the road and the grip to some extent I think. .02

 

replace driver and recheck?