Porsche 928 ST1991 Owner's Manual page 28

Brake pedal
WARNING
• The movement of the brake pedal must
never be obstructed by a floor mat or
any other object. In case one of the two
brake circuits fails, increased pedal
travel is required to bring your vehicle to
a full stop.
• Make sure that the size of your floor mat
does not hamper the movements of
either brake, clutch or accelerator ped-
als in any way.
• Secure the floor mat against sliding into
positions that could interfere with the
safe operation of your vehicle.
• Do not "ride the brakes" by resting your
foot on the pedal when not intending to
brake. Overheating and premature wear
of the brakes will result.
• Before descending a steep grade, re-
duce speed and shift transmission into
a lower gear or driving position to con-
trol speed. Do not ride the brakes or
hold pedal down too long or too often.
This could cause the brakes to get hot
and not function properly.
Brake operation and brake warning light
Make it a habit to check the operation of your
brakes before driving.
The brake fluid warning light in the instru-
ment cluster comes on accompanied by the
fault message in the information system dis-
play to indicate that the level in the brake
fluid reservoir is too low.
With correctly adjusted brakes, and a cor-
rectly working brake system, the pedal travel
to the point of brake actuation should be
1-3/16" to 1-9/16" or 30 to 40 mm. Whenever
the brake pedal travel exceeds this distance,
have the brake system checked.
Keep in mind that the braking distance in-
creases very rapidly as the speed increases.
At 60 mph or 100 km/h, for example, it is not
twice but four times longer than at 30 mph
or 50 km/h. Tire traction is also less effective
when the roads are wet or slippery. There-
fore, always maintain a safe distance from
the car in front of you.
Brake booster
The brake booster assists braking only
when the engine is running.
When the car is moving while the engine is
not running, or if the brake booster is defec-
tive, more pressure on the brake pedal is re-
quired to bring the car to a halt.
Moisture or road salt on brakes affects
braking.
WARNING
Driving through water may reduce the trac-
tion. Moisture on brakes from road water,
car wash, or coating of road salt may affect
braking efficiency. Cautiously apply brakes
to test them after being exposed to such
conditions. When the vehicle is driven on
salted roads for extended periods, the
brakes should be hosed down thoroughly
about every 2 weeks. An automatic car-
wash facility cannot do this job properly.
Brakes will dry after a few cautious brake
applications.
Brake wear
Our automobiles have excellent brakes, but
they are still subject to wear, depending on
how the brakes are used. Have the brake
system inspected at the intervals recom-
mended in your Warranty & Maintenance
booklet.
New brake pads or linings
Brake pads or linings may not have the high-
est possible braking efficiency when new.
Therefore, allow for longer braking distance
during the initial 100 to 150 miles or 150 to
250 kilometers of normal city driving if fewer
stops are realized.
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