1998 GMC ENVOY brakes

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.
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 rnucit 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. Th, ti t 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)
Your vehicle has anti-lock brakes (ABS). ABS is an
advanced electronic braking system that will help
prevent
;1 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.
If there’s a problem with the
anti-lock brake system, this
warning light
will stay on.
See “Anti-Lock Brake
System Warning Light”
in
the Index.
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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
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.
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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Re,member: 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.
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.
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 YOLI may notice some noise, but
this is normal. Your anti-lock brakes work at all
times
-- whether you are in two-wheel or
four-wheel drive.
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.
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.
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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
YOLK speed. While
you’re
in a curve, speed is the one factor you
can control.
Suppose you’re steering through a sharp curve.
Then you suddenly accelerate. Both control
systems
-- steering and acceleration -- have to do
the.ir 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
in
Emergencies” earlier in this section.) It is better to
remove
as much speed as YOLI can from a possible
collision. Then steer around the problem, to
the left or
right depending on the space available.
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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 on
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.
0 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.
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Off-Road Driving with Your GM
Four-Wheel-Drive Vehicle
Also, see "Anti-Lock Brakes" in the Index.
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.
0 The heaviest things should be on the load floor and
forward of
your rear axle. Put heavier items as far
forward as you can.
Be sure the load is secured properly, so driving on
the off-road terrain doesn't toss things around.
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Driving Downhill
When off-roading takes you uownhill, you'll want to
consider
a number of things:
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How steep is the downhill'? Will I be able to maintain
vehicle control?
What's the surface like'? Smooth'? Rough'? Slippery'?
Hard-packed dirt'? Gravel?
Are there hidden surface
obstacles'! Ruts?
Logs? Boulders'?
What's at the
bottom of the hill'! Is there a hidden
creek bank
or even a river bottom with large rocks?
If you decide you can go down a hill safely. then try to
keep your vehicle headed straight down. and use
a low
they won't have to do
all the work. Descend slowly,
keeping your vehicle under control at
all times.
b "ear. This way, engine drag can help your brakes and
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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.
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 ~CI-OSS.
You could roll over
if you don't drive straight down.
Never
go downhill with the transmission in
NEUTRAL (N). This is crdled "free-wheeling." Your
brakes
will have to do all the work and could
overheat and fade.
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Q.' Am I likely to stall when going downhill?
A: It's much nm-e 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.
Shift to PARK (P) and. while still braking. restart
Apply the parking
brake.
the engine.
Shift back to a low gear, release the parking brake,
and drive straight d6wn.
0 If the engine won't start, get out and get
Driving Across an Incline
Sooner or later, an off-road trail will probab lelp. y go
across
the incline
of a hill. If this happens, you have to decide
whether to
try to dri\:e across the incline. Here are some
things to consider:
0 A hill that can be driven straight up or down may be
too steep to drive across. When you
go straight up or
down a
hill, the length of the wheel base (the
distance from the front wheels
to the rear wheels)
reduces the likelihood the vehicle
will tumble end
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over end. But when you drive across an incline, the
much more narrow track width
(the distance between
the left and right wheels) may not prevent the vehicle
from tilting and rolling over.
Also. driving across an
incline puts more weight on the downhill wheels.
This could cause a downhill slide
or a rollover.
Surface conditions can be
a problem when you drive
across
a hill. Loose gravel, muddy spots, or even wet
If the vehicle slips sideways, it can hit something
that
will trip it (a rock, a rut, etc.) and roll over.
Hidden obstacles can make the steepness
of the
incline even worse.
If you drive across a rock with
the
uphill wheels. or if the downhill wheels drop into
a rut or depression, your vehicle can tilt even n1oI-e.
e orass can cause your tires to slip sideways. downhill.
For reasons like these.
you need to decide carefully
whether to
try to drive across an incline. Just because
the trail goes across the incline doesn't mean you have
to drive it. The last vehicle to try it might have
rolled over.
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