Porsche 928 S 1986 Driver Manual page 70

Power-assisted steering
With power-assisted steering, the turning ac-
tion on the steering wheel is assisted by a
hydraulic mechanism. At low engine speeds,
e.g. when parking or when driving slowly, the
power-assisted steering is fully effective. The
power assistance reduces with increasing en-
gine revolutions or increasing vehicle speed
and has the effect of producing increasingly
positive steering action.
The audible rushing noise that occurs at full
steering lock is a characteristic of the design
and does not indicate a fault in the steering
assembly.
Note that when the engine is not running
(when being towed) or when the hydraulic
steering mechanism is faulty, there is no
power-assist action present. In this case,
a greater effort is required to steer the ve-
hicle.
66
Checking the hydraulic fluid
The reservoir is secured in the engine com-
partment on the left-hand wheel housing.
1. Unscrew the reservoir cap.
2. Wipe the dipstick clean. Let the engine run
at idle speed. Screw on the cap and then
screw it off once again. The fluid level should
lie between the upper and lower marks.
Top up with hydraulic fluid if necessary.
The grade of fluid used should be as speci-
fied in the chapter "Filling capacities".
3. Put the cap back on and screw tight.
Changing the air filter
1. Release the fixing clips and remove top of
filter housing complete with filter element.
2. Clean out filter housing and renew the filter
element.
3. Carefully replace top of filter housing and
element, and refasten fixing clips.