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Improved Power Steering

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Old Nov 26, 2006 | 10:57 PM
  #16  
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No problem. I understand completely. I spent a good part of the afternoon cleaning those 10 spokes. It's a bit of work but well worth it. I also bypassed the RDK and cleaned a few grounds on the S4. Just another day in the life.
We'll see what happens next weekend.
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Old Nov 27, 2006 | 04:18 PM
  #17  
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I've also noticed that the steering effort is on the high side.....I also would like lighter steering effort.....so its seems the 91MY cars have the lower friction seal steering rack....HO pump & a different hose.....is that it? I'm sure I'll need to replace my rack eventually.....I wonder if the ligher effort is worth the $$$
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Old Nov 27, 2006 | 07:05 PM
  #18  
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The steering is effort is VERY high. I've been waiting for some conclusive info, so that I can attack the "problem". This high steering effort makes the car feel heavier than what it actually is.. So much so, that my E-class feels much lighter on it's feet. Why? because it has a light yet tight steering feel... Ohhh, I would give anything to have steering like the in my 928..
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Old Nov 27, 2006 | 07:20 PM
  #19  
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The late rack is different the torsion link to the spool valve is weaker allowing for more power assist...
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Old Nov 28, 2006 | 12:18 AM
  #20  
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Jim, would a newer HO pump and new upper hose overcome the difference, or is the rack the real culprit, period?
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Old Nov 28, 2006 | 02:59 PM
  #21  
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Was it Randy V who took his upper PS hose to a hydraulic shop for a replacement with larger inner diameter? I think Randy claimed that the hose replacement alone noticeably improved his steering effort. Interesting that the 91-95 hose w/o restrictor has a similar effect.
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Old Nov 28, 2006 | 03:20 PM
  #22  
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I believe that much of the reduced effort is the very late rack but obviously Porsche felt that they needed to change the pump pressure,the lines and the rack to get what they wanted ...All of the better rebuilt racks have seals designed for the higher pressures and the pump bypass can be adjusted shimmed for higher pressure BUT Porsche added power steering cooling lines to help dispurse the heat generated by churning up the fluid.
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Old Nov 28, 2006 | 04:03 PM
  #23  
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hmmm... interesting reading. i had the rack replaced in my 86 at about 130k when it was leaking and its leaking again now at about 200k. the thing is its much lighter than my 88 on the steering and i dont know if thats the pump or the hose or the rack - is there any way of identifying these 91+ racks?? what about the HO pump, is it different externaly? i definitely prefer the lighter action in the 86 to the heavier action in my 88 and im keen to discover what is the reason, its definitely an improvement in my book.
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Old Nov 28, 2006 | 04:06 PM
  #24  
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Originally Posted by Jim bailey - 928 International
I believe that much of the reduced effort is the very late rack but obviously Porsche felt that they needed to change the pump pressure,the lines and the rack to get what they wanted ...All of the better rebuilt racks have seals designed for the higher pressures and the pump bypass can be adjusted shimmed for higher pressure BUT Porsche added power steering cooling lines to help dispurse the heat generated by churning up the fluid.
I'd like to find out where these higher pressure seals can be had.

EDIT - 06/26/2007 - Haven't had much luck finding anything different than what Corteco supplies in the black and blue bag. I don't think its the seals at all, and agree with JimB that it is the two springs that are changed to allow for "more help" by the pressure.

As you turn the wheel, the spool valve turns with your motion, but if the effort you put on the input shaft increases to a certain point, the valve lets pressure go to the side of the rack that will assist you. The springs that are under the one screw and plate on the side of the spool valve are what controls this assist. When they break, you get no assist, therefore if you increase the strength of the springs, you should get MORE assist earlier.

Last edited by BC; Jun 24, 2007 at 06:32 PM.
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