brake CHEVROLET ASTRO 2003 Owner's Manual

Control of a Vehicle
You have three systems that make your vehicle go where
you want it to go. They are the brakes, the steering and
the accelerator. All three systems have to do their work at
the places where the tires meet the road.
Sometimes, as when you’re driving on snow or ice,
it’s easy to ask more of those control systems than the
tires and road can provide. That means you can lose
control of your vehicle.
Braking
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 (I00 km/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.
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; the condition of your brakes; the weight of
the vehicle and the amount of brake force applied.
4-6

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. 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 Brake System
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You may hear a momentary motor or clicking noise while this test
is going on. This is normal.
ANTI -
LOCK
I I I I
United States Canada
If there’s a problem with the anti-lock brake system, this
warning light will stay on. See
Anti-Lock Brake System
Warning Light on page
3-29.
4-7

Let’s say the road is wet and you’re driving safely.
Suddenly, an animal jumps out in front of you.
You slam on the brakes and continue braking.
Here’s what happens with
ABS:
A computer senses that wheels are slowing down.
If one of the wheels is about to stop rolling, the computer
will separately work the brakes at each front wheel
and at both 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. This can help you steer around
the obstacle while braking hard. As you brake, your computer keeps receiving updates
on wheel speed and controls braking pressure
accordingly.
4-8

Remember: Anti-lock doesn’t change the time you need
to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to the
vehicle in front of you, you won’t have time to apply
your brakes
if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Don’t pump the brakes. Just hold the brake pedal down
firmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise, but
this is normal.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. 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 is not functioning, you can steer but
it will take much more effort.
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.
4-9

Suppose you’re steering through a sharp curve. Then you
suddenly accelerate. Both control systems
- steering
and acceleration
- have to do their work where the tires
meet the road. Adding the sudden acceleration can
demand too much of those places. You can lose control.
What should you do
if this ever happens? Ease up on
the 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.
Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill and find
a truck stopped in your lane, or a car suddenly pulls
out from nowhere, or a child darts out from between
parked cars and stops right in front of you. You can
avoid these problems by braking
- if you can stop
in time. But sometimes you can’t; there isn’t room.
That’s the time for evasive action
- steering around
the problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
See
Braking on page 4-6. It is better to remove as much
speed as you can from a possible collision. Then steer
around the problem, to the left or right depending on the
space available.
4-1 0

Check your mirrors, glance over your shoulder, and
start your left lane change signal before moving out
of the right lane to pass. When you are far enough
ahead of the passed vehicle to see its front in your
inside mirror, activate your right lane change signal
and move back into the right lane. (Remember that
your right outside mirror is convex. The vehicle you
just passed may seem to be farther away from you
than it really is.)
Try not to pass more than one vehicle at a time OD
two-lane roads. Reconsider before passing the
next vehicle.
Don’t overtake a slowly moving vehicle too rapidly.
Even though the brake lamps are not flashing, it may
be slowing down or starting to turn.
If you’re being passed, make it easy for the following
driver to get ahead of you. Perhaps you can ease a
little to the right.
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.
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 vehicle’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 is best handled by easing your foot off
the accelerator pedal.
4-1
3

If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way you want
the vehicle to go. If you start steering quickly enough,
your vehicle may straighten out. Always be ready
for a second skid
if it occurs.
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 recognize warning
clues
- such as enough water, ice or packed snow
on the road to make a “mirrored surface”
- and slow
down when you have any doubt.
Remember: Any anti-lock brake system
(ABS) helps
avoid only the braking skid.
Driving at Night
...s
Night driving is more dangerous than day driving.
One reason is that some drivers are likely to be
impaired
- by alcohol or drugs, with night vision
problems, or by fatigue.
4-1 4

Driving too fast through large water puddles or even
going through some car washes can cause problems,
too. The water may affect your brakes. Try to avoid
puddles. But
if you can’t, try to slow down before you
hit them.
Wet brakes can cause -:cider.--. They w -.j’t
work as well in a quick stop and may cause
pulling to one side. You could lose control
of
the vehicle.
After driving through a large puddle
of water
or a car wash, apply your brake pedal lightly
until your brakes work normally.
4-1 7

If you drive regularly in steep country, or if you’re
planning to visit there, here are some tips that can make
your trips safer and more enjoyable.
Keep your vehicle in good shape. Check all fluid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
0 Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift
to a lower gear when you go
down a steep or long
hill.
0
If you don’t shift down, y--. -.-. ces coul, Jet
so hot that they wouldn’t work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep
downhill slope. Coasting downh.-.
... .rlEUTL .. _L (N) or wit
ignition
off is dangerous. Your brakes will have
to do all the work
of slowing down. They could
get
so hot that they wouldn’t work well. You
would then have poor braking or even none
going down a hill. You could crash. Always have
your engine running and your vehicle in gear
when you go downhill.
e
e
I I
e
Know how to go uphill. You may want to shift down to
a lower gear. The lower gears help cool your engine
and transmission, and you can climb the hill better.
Stay in your own lane when driving on two-lane
roads
in hills or mountains. Don’t swing wide or cut
across the center of the road. Drive at speeds that let
you stay in your own lane.
As you go over the top of a hill, be alert. There could
be something in your lane, like a stalled car or an
accident.
You may see highway signs on mountains that warn
of special problems. Examples are long grades,
passing or no-passing zones,
a falling rocks area
or winding roads. Be alert to these and take
appropriate action.
4-23

What’s the worst time for this? “Wet ice.” Very cold
snow or ice can be slick and hard to drive on. But wet
ice can be even more trouble because it may offer
the least traction of all. You can get wet ice when it’s
about freezing
(32°F; OOC) and freezing rain begins
to fall. Try to avoid driving on wet ice until salt and sand
crews can get there. Whatever
the condition
- smooth ice, packed, blowing
or loose snow
- drive with caution.
Accelerate gently. Try not to break the fragile traction.
If you accelerate too fast, the drive wheels will spin and
polish the surface under the tires even more.
Your anti-lock brakes improve your vehicle’s stability
when you make a hard stop on a slippery road.
Even though you have an anti-lock braking system,
you’ll want to begin stopping sooner than you would
on dry pavement. See
Braking on page 4-6.
Allow greater following distance on any slippery road.
Watch for slippery spots. The road might be fine
until you hit a spot that’s covered with ice. On an
otherwise clear road, ice patches may appear in
shaded areas where the sun can’t reach:
around clumps of trees, behind buildings
or under
bridges. Sometimes the surface of a curve or an
overpass may remain icy when the surrounding
roads are clear. If you see a patch of ice ahead of
you, brake before you are on it. Try not to brake while
you’re actually on the ice, and avoid sudden steering
maneuvers.
4-25