1993 PONTIAC GRAND-PRIX brakes

Your Driving and the Road
. .-
8raking
Braking action involves perception time
and reaction time.
First, you have to decide to push on the
brake pedal. That’s
perception time.
Then you have to bring up your foot
and do it. That’s
reaction time.
Average reaction time is about 3/4 of a
second. But that’s only an average.
It
might be less with one driver and as
long
as two or three seconds or more
with another. Age, physical condition,
alertness, coordination, and eyesight all
play a part.
So do alcohol, drugs and
frustration. But even in
3/4 of a second, a
vehicle moving at
60 mph (100 lun/h)
travels 66 feet (20 m). That could be a
lot
of distance in an emergency, so
keeping enough space between your
vehicle and others
is important.
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~~ ~~ -
And, of course, actual stopping
distances vary greatly with the surface
of the road (whether it’s pavement or
gravel); the condition of the road (wet,
dry, icy); tire tread; and the condition of
your brakes.
Most drivers treat their brakes with
care. Some, however, overwork the
braking system with poor driving habits.
Avoid needless heavy braking. Some
people drive in spurts-heavy
acceleration followed by heavy
braking-rather than keeping pace
with traffic.
This is a mistake. Your
brakes may not have time to cool
between hard stops.
Your brakes will
wear out much faster if you do a lot of
heavy braking.
Don’t “ride” the brakes by letting
your left foot rest lightly on the brake
pedal while driving.
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‘Riding” your brakes can
:ause them to overheat to t
point that they won’t work well.
You might not be able to stop your
vehicle in time to avoid an accident.
If you “ride” your brakes, they will
get
so hot they will require a lot of
pedal force to slow you
&--
Avoid “riding” the brake-. 3
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rs wears them 1 ”)- 2.’;
out much faster. You would need 253
costly brake replacement much 35
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If you keep pace with the traffic and
allow realistic following distances, you
will eliminate a lot of unnecessary
braking. That means better braking and
longer brake life.
If your engine ever stops while you’re
driving, brake normally but don’t
pump your brakes. If you do, the
pedal may get harder to push down. If
your engine stops, you will still have
some power brake assist. But you will
use it when you brake. Once the
power assist is used up, it may take
longer to stop and the brake pedal will
be harder to push.
Anti-Lock Brakes (ABS) (OPTION)
If your Pontiac has this system, it has an
advanced electronic braking system
that
will help prevent skidding.
If you have an anti-lock brake system
(ABS), the brake pedal will say so.
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Your Driving and the Road
Anti-lock Brakes (CONT.)
And this light on the instrument panel
will
go on when you start your vehicle.
When you start your vehicle and begin
to drive away you may hear a
momentary motor or clicking noise and
you may even notice that your brake
pedal moves a little while this is going
on. This is the ABS system testing itself.
If you have your foot on the brake
pedal, this check won't happen until the
vehicle goes about
4 mph (6 ltm/h) or
until you take your foot off the brake
pedal.
After
an ABS stop, you may hear a
clicking noise the next time the vehicle
goes about 4 mph (6 ltdh).
148
If there's a problem with the anti-lock
brake system, the anti-lock brake
system warning light will stay on or
flash. See the
Index under Anti-Lock
Brake
System Warning Light.
Here's how anti-lock works. Let's say
the road is wet. You're driving safely.
Suddenly an animal jumps out in front
You slam on the brakes. Here's what
happens with
ABS.
A computer senses that wheels are
slowing down. The computer separately
works the brakes at each front wheel
and at the rear wheels.
The anti-lock system can change the
brake pressure faster than any driver
could. The computer is programmed to
make the most
of available tire and road
conditions.
of you.
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I
You can steer around the obstacle while To Use Anti-Lock Don’t pump the
braking hard.
brakes. Just hold the brake pedal down
As you brake, your computer keeps and
let anti-lock work for you. You also
receiving updates on wheel speed and
may hear a cliclting noise as you
controls braking pressure accordingly. accelerate
after a hard stop.
Anti-lock doesn’t change the
time you need to get your
foot up to the brake pedal. If you
get too close to the vehicle in front
of you,
you won’t have time to
apply your braltes
if that vehicle
suddenly slows or stops. Always
leave enough
room up ahead to
stop, even though you have
anti-lock brakes.
Disc Brake Wear Indicators
Your Pontiac has four-wheel disc
braltes. Disc brake pads have built-in
wear indicators that make a high-
pitched warning sound when the brake
pads are worn and new pads are needed.
The sound may come and go,
or be
heard all the time your vehicle
is moving
(except when you are pushing on the
brake pedal firmly).
I
A The brake wear warnin&
sound means that sooner
or
later your brakes won’t work well,
That could lead
to an accident.
When you hear the brake wear
warning sound, have
your vehicle
serviced.
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Your Driving and the Road
Disc Brake Wear Indicators
(COWT.)
NOTICE
Continuing to drive with worn-out
brake pads could result in costly
brake repair.
Some driving conditions or climates
may cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean something
is wrong
with your brakes.
Brake linings should always be replaced
as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal does
not return to normal height, or
if there
is a rapid increase in pedal travel. This
could be a sign
of brake trouble.
Brake Adjustment
Every time you make a moderate brake
stop, your disc brakes adjust for wear. If
you rarely make a moderate or heavier
stop, then your brakes might not adjust
correctly. If you drive in that way,
then-very carefully-make a few
moderate brake stops about every
1,000
miles (1 600 km) , so your brakes will
adjust properly.
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Braking In Emergencies
At some time, nearly every driver gets into a situation that requires hard
braking. If you have anti-lock, you can
steer and brake at the same time.
However, if you don’t have anti-lock,
your first reaction-to hit the brake
pedal hard and hold it down-may be
the wrong thing to do. Your wheels
can stop rolling. Once they do, the
vehicle can’t respond to your steering.
Momentum will carry it in whatever
direction it
was headed when the
wheels stopped rolling. That could be
off the road, into the very thing you
were trying to avoid, or into traffic.
If you don’t have anti-lock, use a
“squeeze” braking technique. This will give you
maximum braking while
maintaining steering control. You do
this by pushing on the brake pedal with
steadily increasing pressure.
In an emergency you will probably want
to “squeeze” the brakes hard without
locking the wheels. If you hear or feel
the wheels sliding, ease off the brake
pedal. This will help you retain steering
control. (If you
do have anti-lock, it’s
different: see the
Index under Anti-Lock
Brake System.)
In many emergencies,
steering can help you more than even
the very best braking.
Power Steering
If you lose power steering assist
because the engine stops or the system
fails to function, you can steer but it
will take much more effort.
151
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Your Driving and the Road
Steering Tips-Driving on Curves
It’s important to take curves at a
reasonable speed.
A lot of the “driver lost control”
accidents mentioned on the news
happen on curves. Here’s why:
Experienced driver or beginner, each of
us
is subject to the same laws of physics
when driving on curves. The traction of
the tires against the road surface makes
it possible for the vehicle to change its
path when you turn the front wheels. If
there’s
no traction, inertia will keep the
vehicle going in the same direction. If
you’ve ever tried to steer a vehicle
on
wet ice, you’ll understand this.
The traction you can get in a curve
depends on the condition
of your tires
and the road surface, the angle at which
the curve
is banked, and your speed.
While you’re in
a curve, speed is the one
factor you can control.
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Suppose you’re steering through a
sharp curve. Then you suddenly apply
the brakes. Both control systems-
steering and braking-have to do their
work where the tires meet the road.
Unless you have four-wheel anti-lock
brakes, adding the hard braking can
demand too much at those places. You
can lose control.
The same thing can happen
if you’re
steering through a sharp curve and you
suddenly accelerate. Those two control
systems-steering and acceleration-
can overwhelm those places where the
tires meet the road and make you lose
control.
What should you do if this ever
happens? Let up on the brake or
accelerator pedal, steer the vehicle the
way you want it to go, and slow down. Speed limit signs near curves
warn that
you should adjust your speed. Of
course, the posted speeds are based on
good weather and road conditions.
Under less favorable conditions you’ll
want to
go slower.
If you need to reduce your speed
as you
approach a curve, do it before you enter
the curve, while your front wheels are
straight ahead.
Try to adjust your speed
so you can “drive” through the curve.
Maintain a reasonable, steady speed.
Wait to accelerate until you are out
of
the curve, and then accelerate gently
into the straightaway.
When you drive into a curve at night,
it’s harder to see the road ahead of you
because it bends away from the straight
beams
of your lights. This is one good
reason to drive slower.
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Your Driving and the Road
LOSS of‘ Control
Let’s review what driving experts say
about what happens when the three
control systems (brakes, steering and
acceleration) don’t have enough friction
where the tires meet the road to do
what the driver has asked.
In any emergency, don’t give up. Keep
trying to steer
and constantly seek an
escape route or area of less danger.
Skidding
In a skid, a driver can lose control of
the vehicle. Defensive drivers avoid
most skids by taking reasonable care
suited to existing conditions, and by not
“overdriving” those conditions. But
skids
are always possible.
The three types of skids correspond to
your Pontiac’s three control systems. In
the braking skid your wheels aren’t
rolling. In the steering or cornering
skid, too much speed or steering in a
curve causes tires to slip and lose
cornering force. And in the acceleration
skid too much throttle causes the
driving wheels to spin.
A cornering skid and an acceleration
skid are best handled by easing your
foot
off the accelerator pedal. If your
vehicle starts to slide (as when you turn
a corner
on a wet, snow- or ice-covered
road), ease your foot
off the accelerator
pedal as
soon as you feel the vehicle start to
slide. Quickly steer the way you
want the vehicle to go.
If you start
steering quickly enough, your vehicle
will straighten out.
As it does, straighten
the front wheels.
Of course, traction is reduced when
water, snow, ice, gravel, or other
material is
on the road. For safety, you’ll
want to slow down and adjust your
driving to these conditions. It
is
important to slow down on slippery
surfaces because stopping distance will
be longer and vehicle control more
limited.
While driving
on a surface with reduced
traction, try your best to avoid sudden
steering, acceleration, or braking
(including engine braking
by shifting to
a lower gear). Any sudden changes
could cause the tires to slide. You may
not realize the surface
is slippery until
your vehicle is skidding. Learn to
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