1995 GMC SIERRA brakes

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 tinze 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 reuction tinze 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 (1 00 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; and the condition
of your brakes.
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.
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Anti-Lock Brakes (ABS)
Your vehicle has an advanced electronic braking system that can help you
keep it under control. When you start your vehicle and begin to drive away,
you may hear a momentary motor or clicking noise. This is the
ABS system
testing itself.
Here's how anti-lock works. Let's say the road is wet. You're driving safely.
Suddenly an animal jumps out
in front of you.
You slam on the brakes. 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 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.
You can 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 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 brakes if that vehicle suddenly slows or
stops. Always leave enough room up ahead to stop, even though
you have
anti-lock brakes.
To Use Anti-Lock
Don’t pump the brakes. Just hold the brake pedal down and let anti-lock
work for you. You may feel the brakes vibrate, or you may notice some
noise, but this is normal. On vehicles
with four-wheel drive, your anti-lock
brakes work at all times
- whether you are in two-wheel drive or
four-wheel drive.
Braking in Emergencies
Use your anti-lock braking system when you need to. 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.
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’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
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 fivorable 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. Wdit 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 in Emergencies” earlier
in this section.) 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.
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Try not to pass more than one vehicle at a time on two-lane roads.
Reconsider before passing the next vehicle.
0 Don’t overtake a slowly moving vehicle too rapidly. Even though the
brake lights 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.
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 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, 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.
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Driving Guidelines
Off-Road Driving with Your Four-wheel Drive
Vehicle
This off-road guide is for vehicles that have four-wheel drive.
Also, see “Anti-Lock Brakes”
in the Index.
If your vehicle doesn’t have four-wheel drive, you shouldn’t drive off-road
unless you’re
on a level, solid surface.
Off-road driving can be great fun. But it does have some definite hazards.
The greatest of these
is the terrain itself.
“Off-roading” means you’ve left the great North American road system
behind. Traffic lanes aren’t marked. Curves aren’t banked. There are no
road signs. Surfaces can
be slippery. rough, uphill or downhill. In short,
you’ve gone right back to nature.
Off-road driving involves some new skills. And that’s why it’s very
important that
you read this guide. You’ll find many driving tips and
suggestions. These will help make your off-road driving safer and more
enjoyable.
Before You Go Off-Roading
There are some things to do before you go out. For example, be sure to have
all necessary maintenance and service work done. Check to make sure all
underbody shields
(if so equipped) are properly attached. Be sure you read
all the information about your four-wheel drive vehicle in this manual.
Is
there enough fuel? Is the spare tire fully inflated? Are the fluid levels up
where they should be? What are
the local laws that apply to off-roading
where you’ll be driving?
If you don’t know, you should check with law
enforcement people in the area. Will you be
on someone’s private land? If
so, be sure to get the necessary permission.
Loading Your Vehicle for Off-Road Driving
There are some important things to remember about how to load your
vehicle.
The heaviest things should be on the load floor and forward of your
rear axle. Put heavier items as far forward
as you can.
doesn’t toss things around.
Be sure the load is secured properly, so driving on the off-road terrain
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If you decide you can go down a hill safely, then try to keep your vehicle
headed straight down, and use a low gear. This way, engine drag can help
your brakes and they won’t have to do all
the work. Descend slowly,
keeping your vehicle under control at all times.
A CAUTION:
Heavy braking when going down a hill can cause your brakes to
overheat and fade. This could cause
loss of control and a serious
accident. Apply the brakes lightly when descending
a hill and
use a low gear to keep vehicle speed under control.
Q: Are there some things I should not do when driving down a hill?
A: Yes! These are important because if you ignore them you could lose
control and have a serious accident.
When driving downhill, avoid turns that take you across the incline of
the hill. A hill that’s not too steep to drive down may be too steep to
drive across.
You could roll over if you don’t drive straight down.
Never go downhill with the transmission in NEUTRAL (N) , or with
the clutch pedal depressed in a manual shift
. This is called
“free-wheeling.” Your brakes will have to do all the work and could
overheat and fade.
Q: Am I likely to stall when going downhill?
A: It’s much more likely to happen going uphill. But if it happens going
downhill, here’s what
to do.
0 Stop your vehicle by applying the regular brakes. Apply the parking
brake.
Shift to PARK (P) (or to Neutral with the manual transmission) and,
while still braking, restart the engine.
down.
Shift back to a low gear, release the parking brake, and drive straight
If the engine won’t start, get out and get help.
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Hard packed snow and ice offer the worst tire traction. On these surfaces,
it’s very easy
to lose control. On wet ice, for example, the traction is so poor
that you will have difficulty accelerating. And if you do get moving, poor
steering and difficult braking can cause you to slide
out of control.
A CAUTION:
Driving on frozen lakes, ponds or rivers can be dangerous.
Underwater springs, currents under the ice, or sudden thaws
can weaken the ice. Your vehicle could fall through the ice and
you and your passengers could drown. Drive your vehicle on
safe surfaces only.
Driving In Water
Light rain causes no special off-road driving problems. But heavy rain can
mean flash flooding, and flood waters demand extreme caution.
Find out how deep the water is before
you drive through it. If it’s deep
enough to cover your wheel hubs, axles, or exhaust pipe, don’t try
it - you
probably won’t get through. Also, water that deep can darnage your axle and
other vehicle parts.
If the water isn’t too deep, then drive through
it slowly. At fast speeds, water
splashes
on your ignition system and your vehicle can stall. Stalling can also
occur if you get your tailpipe under water. And, as long as your tailpipe is
under water, you’ll never be able to start your engine. When
you go through
water, remember that when your brakes get wet,
it may take you longer to
stop.
A CAUTION:
Driving through rushing water can be dangerous. Deep water
can sweep your vehicle downstream and you and your
passengers could drown.
If it’s only inches deep, it can still wash
away the ground
from under your tires, and you could lose
l traction and roll the vehicle over. Don’t drive through rushing
water.
If you have a diesel engme, see “Driving Through Water (Diesel Engines)”
in the Index for more information on driving through water.
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