1993 GMC SIERRA brakes

has an effect on steering, accelerating, and braking. You may want to reduce
the air pressure in your tires slightly when driving on sand. \
This will improve
traction.
Hard packed snow and ice offer the worst tire traction. On th\
ese surfaces, it’s
very easy to lose control. On wet ice, for example, the tract\
ion
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.
I A Driving on frozen lakes, ponds or rivers can be dangerous. I
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
on
I y.
.
Driving In Water
Light rain causes no special off-road driving problems. But hea\
vy 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. S\
talling can also
occur
if you get your tailpipe under water. And, as long as your tailp\
ipe is
under water, you’ll never be able to start your engine. Whe\
n 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 inches deep, it can still wash away the ground
from under your tires, and you could lose traction and roll t\
he vehicle
over. Don’t drive throuah rushina water. I
If you have a diesel engine, see “Driving Through Water (Diese\
l Engines)” in
the Index for more information on driving through water.
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The heavier the rain, the harder it is to see. Even if your windshield wiper
blades are in good shape, a heavy rain can make it harder to see road signs
and traffic signals, pavement markings, the edge of the road, and even
people walking. Road spray can often be worse for vision than \
rain,
especially
if it comes from a dirty road.
So it is wise to keep your wiping equipment in good shape and keep you\
r
windshield washer tank filled. Replace your windshield wiper ins\
erts when they show signs of streaking or missing areas on the windshield,
or when strips of
rubber start
to separate from the inserts.
.
AM455017 4
Driving too fast through large water puddles or even going through some car
washes can cause problems,
too. The water may affect your brakes. Try to
avoid puddles. But
if you can't, try to slow down before you hit them.
Wet brakes can cause accidents. They won't work well in a quick
d stop and may cause pulling to one side. You could lose control of
the vehicle.
After driving through a large puddle of water or a car wash, apply
your brake pedal lightly until your brakes work normally.
Hydroplaning
Hydroplaning is dangerous. So much water can build up under your tires that
they can actually ride on the water. This can happen
if the road is wet
enough and you're going fast enough. When your vehicle is hydr\
oplaning,
it
has little or no contact with the road.
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As in any driving situation, keep pace with traffic and allow adequat\
e
following distances.
Hill and Mountain Roads
I r
AM470001
Driving on steep hills or mountains is different from driving in flat or rolling
terrain.
If you drive regularly in steep country, or if you’re planning to visit
there, here are some tips that can make your trips safer and \
more enjoyable.
(See “Off-Road” in the Index for information about driving off-road.)
Keep your vehicle in good shape. Check all fluid levels and also the
brakes, tires, cooling system and transmission. These parts can \
work
hard on mountain roads.
Know how to go down hills. The most important thing to know is this: let
your engine do some
of the slowing down. Don’t make your brakes do it
all. Shift to a lower gear when you go down a steep or long hill. That
way, you will slow down without excessive use of your brakes.
If you don’t shift down,’ your brakes could get so hot that they
- b wouldn’t work well. You would then have poor braking or even none
going
down a hill. You could crash. .Shift down to let your engine
assist your brakes on a steep downhill slope. I I
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I CAUTION
A Coasting downhill in N (Neutral) or with the ignition off is dangerous.
E ‘ Your brakes will have to do all the work of slowing down. They could
get
so hot that they wouldn’t work well. You could crash. Always
have your engine running and your vehicle in gear when you go
downhill.
l I
e
e
e
e
e
Know how to go uphill. You may want to shift down to a lower gear.
The lower gears help cool your engine and transmission, and yo\
u can
climb the hill better.
Stay .in your own lane when driving on two-lane roads in hills or
mountains. Don’t swing wide
or cut across the center of the road. Drive
at speeds that let you stay in your own lane. That way, you won’t be
surprised by a vehicle coming toward you in the same lane.
It takes longer to pass another vehicle when you’re going uphill. You’ll
want
to leave extra room to pass. If a vehicle is passing you and
doesn’t have enough room,
slow down to make it easier for the other
vehicle to get by.
As you go over the top of a hill, be alert. There could be something in
your lane, like a stalled car
or an accident.
You may see highway signs on mountains that warn of special problems.
Examples are long grades, passing or no-passing zones, a fallin\
g rocks
area, or winding roads. Be alert to these and take appropriate action.
Winter driving can present special problems. See “Winter Driv\
ing” in the
Index.
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AM48001 7
What’s the worst time for this? “Wet ice.’’ Very cold snow or ice can be slick
and hard to drive on. But wet ice can be even more trouble because it may
offer the least traction of all. You can get “wet ice” when it’s about freezing
(32°F; 0°C) and freezing rain begins to fall. Try to avoid driving on wet ice
until salt and sand crews can get there.
Whatever the condition-smooth ice, packed, blowing or loose snow-drive
with caution. Accelerate gently. Try not to break the fragile \
traction.
If you
accelerate
too fast, the drive wheels will spin and polish the surface under \
the tires even more.
Your anti-lock brakes improve your ability
to make a hard stop on a slippery
road. Even though you have the anti-lock braking system, you’\
ll want to begin
stopping sooner than you would on dry pavement. See “Anti-lo\
ck‘’ in the Index.
Allow greater following distance on any slippery road.
Watch for slippery spots. The road might be fine until you hi\
t a spot
that’s covered with ice. On an otherwise clear road, ice patches may
appear in shaded areas where the sun can’t reach: around clumps of
trees, behind buildings,
or under bridges. Sometimes the surface of a
curve
or an overpass may remain icy when the surrounding roads are
clear.
If you see a patch of ice ahead of you, brake before you are on
it. Try not to brake while you’re actually on the ice, and\
avoid sudden
steering maneuvers.
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AM480043
Run your engine only as long as you musk. This saves fuel. When you run
the engine, make it go a little faster than just idle. That is, push the
accelerator slightly. This uses less fuel for the heat that yo\
u get and
it keeps
the battery (or batteries) charged. You will need a well-charged battery (or
batteries) to restart the' vehicle, and possibly for signaling later on with your
headlights. Let the heater run for awhile.
If you 'have a diesel engine, you
may have to run it at a higher speed
to lget enough heat. Then, shut the
engine
off and close the window almost all the way to preserve the heat.
Start the engine again and repeat this only when you feel really
uncomfortable from the cold. But
do it as little as'possible. Preserve the fuel
as long as you can.
To help keep warm, you can get out of the vehicle and
do some fairly vigorous exercises every half hour or so until help comes.
If You're Stuck in Deep Snow
This manual explains how to get the vehicle out of deep snow without
damaging it. See "Rocking Your Vehicle" in the Index.
Towing a mailer
CAUTION I
If you don't use the correct equipment and drive properly, you ca\
n
lose control when you pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well-or even at all. You and your
passengers could be seriously injured. Pull a trailer only if \
you have
followed all the steps in this section.
I
i'- ." "
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Your Driving and the Road
Total Weight on Your Vehicle’s Tires
Be sure your vehicle’s tires are inflated to the limit for cold tires. You’ll find
these numbers on the Certification label at the rear edge of the driver’s door
(or see “Tire Loading” in the Index). Then be sure you don’t go over the
GVW limit for your vehicle.
Hitches
It’s important to have the correct hitch equipment. Crosswinds, large trucks
going by, and rough roads are a few reasons why you’ll need the righ\
t hitch.
Here are some rules
to follow:
If your vehicle has a step bumper and you are going to use a ball-type
hitch, remove the pad and cut holes in
it to match the hitch and safety
chain holes in the bumper.
If you’ll be pulling a trailer that, when loaded, will weigh more than 4,000
pounds (1800 kg) be sure to use a properly mounted weight-distributing
hitch and sway control of the proper size. This equipment is very
important for proper vehicle loading and good handling when you\
’re
driving.
Safety Chains
You should always attach chains between your vehicle and your trail\
er. Cross
the safety chains under the tongue of the trailer
so that the tongue will not
drop
to the road if it becomes separated from the hitch. Instructions about
safety chains may be provided by the hitch manufacturer
or by the trailer
manufacturer. Follow the manufacturer’s recommendation for atta\
ching safety
chains. Always leave just enough slack
so you can turn with your rig. And,
never allow safety chains to drag .on the ground.
Trailer Brakes
If your trailer weighs more than 1,000 pounds (450 kg) loaded, then it needs
its own brakes-and they must be adequate. Be sure
to read and follow the
instructions for the trailer brakes
so you’ll be able to install, adjust and
maintain them properly.
Don’t tap into your vehicle’s brake system
if the trailer’s brake system will use
more than
0.02 cubic inch (0.3~~) of fluid from your vehicles master cylinder.
If it does, both braking systems won’t work well. You could even lose your
brakes.
Will the trailer brake parts take 3,000 psi (20 650 kPa) of pressure? If
not, the trailer brake system must not be used with your vehi\
cle.
If everything checks out this far, then make the brake fluid tap at the
port on the master cylinder that sends fluid
to the rear brakes. But don’t
use copper tubing for this.
If you do, it will bend and finally break off.
Use steel brake tubing.
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Driving with a Trailer
Towing a trailer requires a certain amount of experience. Before setting out
for the open road, you’ll want to get to know your rig. Acquaint yourself with
the feel of handling and braking with the added weight of the trailer. And
always keep in mind that the vehicle you are driving is now a good deal
longer and not nearly
so responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform, safety \
chains, electrical
connector, lights, tires and mirror adjustment.
If the trailer has electric brakes,
start your vehicle and trailer moving and then apply the trailer brake controller
by hand to be sure the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the load is secure, and
that the lights and any trailer brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as you w\
ould when
driving your vehicle without a trailer. This can help you avoid situations \
that
require heavy braking and sudden turns.
Passing
You’ll need more passing distance up ahead when you’re towing a trailer.
And, because you’re a good deal longer, you’ll need to g\
o much farther beyond the passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand. Then, to move the
trailer left, just move your hand to the left.
To move the trailer to the right,
move your hand to the right. Always back up slowly and,
if possible, have
someone guide you.
Making Turns
When you’re turning with a trailer, make wider turns than normal. Do this so
your trailer wheels won’t strike soft shoulders, curbs, road signs\
, trees, or
other objects. Avoid jerky or sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have a different turn signal
flasher and extra wiring. The green arrows on your instrument \
panel will flash
whenever you signal a turn or lane change. Properly hooked up, the trailer
lights will also flash, telling other drivers you’re about t\
o turn, change lanes,
or stop.
When towing a trailer, the green arrows on your instrument pan\
el will flash for
turns even
if the bulbs on the trailer are burned out. Thus, you may think
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