1998 GMC SIERRA brakes

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 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 -
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
I LOCK I the Index. 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.
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The anti-lock system can change the brlzke 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. 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. 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
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.
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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
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.
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’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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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
firel‘?
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 downhill, you’ll want to
consider
a number of things:
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 surfxe 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
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.
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
0
0
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.
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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.
Stop your vehicle by applying the regular brakes.
Apply the parking brake.
Shift to PARK (Pj (or to NEUTRAL (Nj with the
manual transmission) and, while still braking, restart
the engine.
Shift back to a low gear, release the parking brake,
and drive straight down.
0 If the engine won't start, get out and get help.
Driving Across an Incline
Sooner or later, an off-road trail will probably go across
the incline of a
hill. If this happens, you have to decide
whether to try to drive across the incline. Here are some
things to consider:
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 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
grass can cause your tires to slip sideways, downhill.
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 more.
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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__ ~~~~~ ~ ~~ ~ ~ ~ . _~_
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 damage 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.
.
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 shallow water, it can still wash away the
ground from under your tires, and you could lose
traction and roll the vehicle over. Don’t drive
through rushing water.
See “Driving Through Water’’ in the Index for more
information on driving through water.
After Off-Road Driving
Remove any brush or debris that has collected on the
underbody, chassis or under the hood. These
accumulations can be a fire hazard.
After operation in mud or sand, have the brake linings
cleaned and checked. These substances can cause
glazing and uneven braking. Check the body structure,
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