2000 GMC YUKON brakes

4-7
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 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.
If there's a problem with
the anti
-lock brake system,
this warning light will stay
on. See ªAnti
-Lock Brake
System Warning Lightº in
the Index.

4-8
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.

4-9
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.
Traction Assist System (Option)
Your vehicle may have a Traction Assist System (TAS)
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 rear wheels are spinning
or beginning to lose traction. When this happens, the
system reduces engine power to limit wheel spin.
This light will come
on when the TAS is
limiting wheel spin.
See ªLow Traction Lightº
in the Index.
You may hear or feel the system working or notice a
lack of accelerator response, but this is normal.
The Traction Assist System may operate on dry roads
under some conditions. When this happens, you may
notice a reduction in acceleration. This is normal and
doesn't mean there's a problem with your vehicle.
Examples of these conditions include a hard acceleration
in a turn, an abrupt upshift or downshift of the
transmission or driving on rough roads.

4-12
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. Refer to
ªTraction Assist Systemº in the Index.
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 ªdriveº 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 ªBraking in
Emergenciesº 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.

4-15

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
if 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.

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 ªoverdrivingº 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.

4-16
A cornering skid is best handled by easing your foot off
the accelerator pedal. If you have the ªTraction Assist
System,º 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'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
ªmirrored surfaceº
-- and slow down when you
have any doubt.
Remember: Any anti
-lock brake system (ABS) helps
avoid only the braking skid.
Off-Road Driving with Your
Four
-Wheel-Drive Vehicle
This off-road guide is for vehicles that have
four
-wheel drive.
Also, see ªAnti
-Lock Brakesº 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.
ªOff
-roadingº 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.

4-26 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 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
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.
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). This is called ªfree
-wheeling.º
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.

Stop your vehicle by applying the regular brakes.
Apply the parking brake.

Shift to PARK (P) and, while still braking, restart
the engine.

Shift back to a low gear, release the parking brake,
and drive straight down.

If the engine won't start, get out and get help.

4-30
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.
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 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 ªDriving Through Waterº 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,
steering, suspension, wheels, tires and exhaust system
for damage. Also, check the fuel lines and cooling
system for any leakage.
Your vehicle will require more frequent service due to
off
-road use. Refer to the Maintenance Schedule for
additional information.