[s-cars] 1995 S6 Steering Pump

[Paul Gailus]

I kind of doubt that disconnecting the plug to the steering rack
is really going to improve the life of the hydraulic pump, because
I don't think the pump pressure or flow is going to be
significantly affected.

The Servotronic system changes how much opposing torque
is provided at the steering wheel by the reaction piston, and
therefore how much simulated feedback is provided to the driver.
It does this by adjusting the duty cycle of the modulator valve
connected to this plug, and therefore the hydraulic pressure and
force on the reaction piston when the steering wheel is turned.
When the car is stopped, little if any force is applied to the reaction
piston so the steering wheel is easy to turn. By disconnecting the
plug, the modulator valve will provide for a relatively high level of
reaction force independent of how fast the car is going.  However,
most of the force turning the wheels is still going to be applied by
the main servo piston on the steering rack, and a relatively small
amount from the torque applied to the pinnion. So I would think
that the pump pressure and flow should hardly be affected.

Paul


----- Original Message -----
From: Brian Powell <brian at atomicham.com>
To: <bnautical at yahoo.com>
Cc: <s-car-list at audifans.com>
Sent: Tuesday, March 04, 2003 12:20 PM
Subject: Re: [s-cars] 1995 S6 Steering Pump


> Though others have answered regarding the repair, I ponder the
> following:
>
> Are many of these power steering pump problems due to the stupid
> Cadillac like overboost that the S4/6's do at low speeds?  I
> disconnected the plug to overboost at low speeds and my car feels
> better (can't spin the wheel with my pinky) and have had no power
> steering problems.
>
> My 20v has a similar power steering pump setup to the 20v turbo S6 and
> it doesn't have overboost and it is still running great at over 160k
> miles.
>
> People might disconnect the electrical plug at the steering rack that
> controls the overboost and see if many of their problems stop recurring.
>
> Cheers,
> Brian
>
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