2004 CHEVROLET VENTURE brakes

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 are driving on snow or ice, it
is 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 involvesperception timeand
reaction time.
First, you have to decide to push on the brake pedal.
That isperception time.Then you have to bring up your
foot and do it. That isreaction time.
Averagereaction timeis about 3/4 of a second. But that is
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 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 is 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.
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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 are driving, brake
normally but do not 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 (ABS)
Your vehicle may have anti-lock brakes. ABS is an
advanced electronic braking system that will help
prevent a braking skid.
If your vehicle has anti-lock
brakes, this warning light
on the instrument panel will
come on briey when
you start your vehicle.
When you start your engine, or when you 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, and you may even notice that
your brake pedal moves or pulses a little. This is normal.
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Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is 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 wheel.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.
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Remember: Anti-lock does not 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 will not 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
Do not pump the brakes. Just hold the brake pedal
down rmly and let anti-lock work for you. You may feel
a slight brake pedal pulsation or notice some noise,
but this is normal.
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 do not have anti-lock, your
rst reaction — to hit the brake pedal hard and hold
it down — may be the wrong thing to do. Your wheelscan stop rolling. Once they do, the vehicle can not
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 do not have anti-lock, use a “squeeze” braking
technique. This will give you maximum braking
while maintaining steering control. You can 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 youdohave
anti-lock, it is different. See “Anti-Lock Brake System”
in this section.
In many emergencies, steering can help you more than
even the very best braking.
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Traction Control System (TCS)
Your vehicle may have a traction control system that
limits wheel spin. This is especially useful in slippery
road conditions. The system operates only if it senses
that one or both of the front wheels are spinning or
beginning to lose traction. When this happens,
the system works the front brakes and reduces engine
power to limit wheel spin.
The TRACTION ACTIVE message will come on when
the traction control system is limiting wheel spin.
SeeTraction Active Message on page 3-42. You may
feel or hear the system working, but this is normal.
If your vehicle is in cruise control when the traction
control system begins to limit wheel spin, the cruise
control will automatically disengage. When road
conditions allow you to safely use it again, you may
reengage the cruise control. See “Cruise Control” under
Turn Signal/Multifunction Lever on page 3-6.If this message comes on and stays on or comes on
while you are driving, there’s a problem with your
traction control system.
SeeService Traction System Warning Message on
page 3-41. When this warning message is on, the
TRAC OFF light will come on to remind you that the
system will not limit wheel spin. Adjust your driving
accordingly.
The traction control system automatically comes on
whenever you start your vehicle. To limit wheel spin,
especially in slippery road conditions, you should always
leave the system on. But you can turn the traction control
system off if you ever need to. You should turn the
system off if your vehicle ever gets stuck in sand, mud or
snow and rocking the vehicle is required. See “Rocking
Your Vehicle” underIf You Are Stuck: In Sand, Mud, Ice
or Snow on page 4-32. United States
Canada
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Steering
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 is important to take curves at a reasonable speed.
A lot of the “driver lost control” accidents mentioned on
the news happen on curves. Here is 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 is no traction, inertia
will keep the vehicle going in the same direction. If
you have ever tried to steer a vehicle on wet ice, you
will 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 are
in a curve, speed is the one factor you can control.Suppose you are 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 of those places. You can lose control.
The same thing can happen if you are 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. SeeTraction Control
System (TCS) on page 4-10.
What should you do if this ever happens? Ease 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 will 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.
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Steering in Emergencies
There are times when steering can be more effective
than braking. For example, you come over a hill and nd
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 not; there is not
room. That is the time for evasive action — steering
around the problem.
Your vehicle can perform very well in emergencies like
these. First apply your brakes.
SeeBraking 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.An emergency like this requires close attention and a
quick decision. If you are holding the steering wheel at
the recommended 9 and 3 o’clock positions, you
can turn it a full 180 degrees very quickly without
removing either hand. But you have to act fast, steer
quickly, and just as quickly straighten the wheel
once you have avoided the object.
The fact that such emergency situations are always
possible is a good reason to practice defensive driving
at all times and wear safety belts properly.
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Loss of Control
Let us review what driving experts say about what
happens when the three control systems (brakes,
steering and acceleration) do not have enough friction
where the tires meet the road to do what the driver
has asked.
In any emergency, do not 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 vehicle’s
three control systems. In the braking skid, your wheels
are not 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.
If you have the Traction Control System, remember: It
helps avoid only the acceleration skid. If you do not have
this system, or if the system is off, then an acceleration
skid is also best handled by easing your foot off the
accelerator pedal.
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 will 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.
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