brake GMC SIERRA 2001 Workshop Manual

4-34
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.
It's wise to keep your wiping equipment in good shape and
keep your windshield washer tank filled with washer fluid.
Replace your windshield wiper inserts when they show
signs of streaking or missing areas on the windshield, or
when strips of rubber start to separate from the inserts.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.
CAUTION:
Wet brakes can cause accidents. They won't work
as well in a quick 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 hydroplaning,
it has little or no contact with the road.

4-40
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 ªOff
-Road Drivingº 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. Shift to a lower gear when you go
down a steep or long hill.
CAUTION:
If you don't shift down, your brakes could get so
hot that they 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.
CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have to
do all the work of slowing down. They could get so
hot that they wouldn't work well. You would then
have poor braking or even none going down a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.

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 you 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.

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 falling rocks area or winding
roads. Be alert to these and take appropriate action.

4-42
What's the worst time for this? ªWet ice.º 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 (32F; 0C) 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 vehicle's stability
when you make a hard stop on a slippery road. Even
though you have an anti
-lock braking system, you'll
want to begin stopping sooner than you would on dry
pavement. See ªAnti
-Lockº in the Index.

Allow greater following distance on any
slippery road.

Watch for slippery spots. The road might be
fine until you hit 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.

4-46 Four-Wheel-Drive Vehicles
CAUTION:
Shifting the transfer case into NEUTRAL can
cause your vehicle to roll even if the transmission
is in PARK (P), for an automatic transmission,
or if your vehicle is in gear, for a manual
transmission. You or others could be injured.
Make sure the parking brake is firmly set before
you shift the transfer case into NEUTRAL.
Use the following procedure to correctly tow your
vehicle on all four wheels:
1. Firmly set the parking brake.
2. Shift an automatic transmission to PARK (P),
or a manual transmission to FIRST (1).
3. Securely attach the vehicle being towed to the
tow vehicle.
4. Shift the transfer case to NEUTRAL (N).
See ªFour
-Wheel Driveº in the Index for the
proper procedure to select the neutral position for
your vehicle.
5. Release the parking brake only after the vehicle
being towed is firmly attached to the towing vehicle.
6. Turn the ignition to OFF. The OFF position unlocks
the steering column and reduces battery drain as long
as the IGN 0 fuse is removed. Unlocking the steering
column will allow the proper movement of the front
wheels and tires during towing.

4-52
For example, adding a 700 lb. (318 kg) snow plow
actually adds more than 700 lb. (318 kg) to the
front axle. Using the formula, if the snow plow is
4 ft. (122 cm) in front of the front axle and the
wheel base is 10 ft. (305 cm), then:
W=700 lb. (318 kg)
A=4 ft. (122 cm)
W.B.=10 ft. (305 cm)
(W x (A + W.B.))/W.B.= (700 x (4 + 10))/10 =
980 lb. (445 kg)
So, if your truck's front axle reserve capacity is
more than 980 lb. (445 kg), you could add this
snow plow without exceeding the front GAWR.
Q:What if I want to add heavier equipment to
my vehicle?
A:You can add heavier equipment on the front of the
vehicle if you compensate for it by carrying fewer
passengers, less cargo, or by positioning cargo more
towards the rear. This has the effect of reducing the
load on the front. However, the front GAWR, rear
GAWR and the GVWR must never be exceeded.
CAUTION:
On some vehicles equipped with certain front
mounted equipment, such as a snow plow, it may
be possible to load the front axle to the front
GAWR but not have enough weight on the rear
axle to have proper braking performance.
If your brakes can't work properly, you could
have a crash. To help your brakes work properly
when a snow plow is installed, always follow
the snow plow manufacturer or installer's
recommendation for rear ballast to ensure a
proper front and rear weight distribution ratio,
even though the actual front weight may be less
than the front GAWR, and the total vehicle
weight is less than the GVWR. Maintaining a
proper front and rear weight distribution ratio is
necessary to provide proper braking performance.

4-55
Your dealer can help you make a good vehicle-camper
match. He'll also help you determine your CWR.
After you've loaded your vehicle and camper, drive to
a weigh station and weigh the front and rear wheels
separately. This will tell you the loads on your axles.
The loads on the front and rear axles shouldn't be more
than either of the GAWRs. The total of the axle loads
should not be more than the GVWR.
Open your driver's door and look at the
Certification/Tire label to find out your GAWR
and GVWR.
If you've gone over your weight ratings, move or
take out some things until all the weight falls below
the ratings. Of course, you should always tie down
any loose items when you load your vehicle or camper.
When you install and load your slide
-in camper,
check the manufacturer's instructions.
If you want more information on curb weights, cargo
weights, Cargo Weight Rating and the correct center of
gravity zone for your vehicle, your dealer can help you.
Just ask for a copy of ªConsumer Information,
Truck
-Camper Loading.º
Trailer Recommendations
You must subtract your hitch loads from the CWR
for your vehicle. Weigh your vehicle with the trailer
attached, so that you won't go over the GVWR or
GAWR. If you are using a weight
-distributing hitch,
weigh the vehicle without the equalizer bars in place.
You'll get the best performance if you spread out the
weight of your load the right way, and if you choose the
correct hitch and trailer brakes.
For more information, see ªTrailer Towingº in
the Index.
Camper Wiring Harness
(If Equipped)
If your vehicle is equipped with a camper wiring
harness, see ªTrailer Wiring Harnessº in the Index
for further information.

4-56
Pickup Conversion to Chassis Cab
General Motors is aware that some vehicle owners
may consider having the pickup box removed and a
commercial or recreational body installed. Before you
do so, first contact the GM Customer Assistance
Office for your area for information on such conversions
specific to this vehicle. See the ªWarranty and Owner
Assistanceº booklet for Customer Assistance Office.
Owners should be aware that, as manufactured, there
are differences between a chassis cab and a pickup
with the box removed which may affect vehicle safety.
The components necessary to adapt a pickup to permit
its safe use with a specialized body should be installed
by a body builder in accordance with the information
available from the Customer Assistance Office.
Towing a Trailer
CAUTION:
If you don't use the correct equipment and drive
properly, you can 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. Ask your dealer for
advice and information about towing a trailer
with your vehicle.

4-73 Safety Chains
You should always attach chains between your vehicle
and your trailer. Cross the safety chains under the
tongue of the trailer to help prevent the tongue from
contacting 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.
For trailers up to 5,000 lbs. (2 270 kg) you may
attach the safety chains to the attaching points on the
bumper. For heavier trailers, follow the trailer or hitch
manufacturer's recommendation for attaching safety
chains. Always leave just enough slack so you can
turn with your rig. Never allow safety chains to drag
on the ground.
Trailer Brakes
If your trailer weighs more than 2,000 lbs. (900 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.Your trailer brake system can tap into the vehicle's
hydraulic brake system only if:

The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.

The trailer's brake system will use less than
0.02 cubic inch (0.3 cc) of fluid from your vehicle's
master cylinder. Otherwise, both braking systems
won't work well. You could even lose your brakes.
If everything checks out this far, make the brake tap at
the port on the master cylinder that sends the 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.
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 as
responsive as your vehicle is by itself.

4-74
Before you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, 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 lamps and any trailer brakes
are still working.
While towing a trailer or when exposed to long periods
of sunshine, the floor of the truck bed may become very
warm. Avoid putting items in the truck bed that might be
affected by high ambient temperatures.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would 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 go 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 to the left, just move that
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
NOTICE:
Making very sharp turns while trailering could
cause the trailer to come in contact with the
vehicle. Your vehicle could be damaged. Avoid
making very sharp turns while trailering.
When you're turning with a trailer, make wider turns than
normal. Do this so your trailer won't strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.

4-75 Turn Signals When Towing a Trailer
The arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you're about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will flash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind you
are seeing your signal when they are not. It's important
to check occasionally to be sure the trailer bulbs are
still working.
Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If you don't shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
If you have an automatic transmission, you can tow in
DRIVE (D). You may want to shift the transmission
to THIRD (3) or, if necessary, a lower gear selection if
the transmission shifts too often (e.g., under heavy loads
and/or hilly conditions).You may also want to activate the tow/haul mode if the
transmission shifts too often. See ªTow/Haul Modeº in
the Index.
If you have a 5
-speed manual transmission and you are
towing a trailer, it's better not to use FIFTH (5) gear.
Just drive in FOURTH (4) gear (or, as you need to,
a lower gear).
If you have a 6
-speed manual transmission and you
are towing a trailer, it's better not to use SIXTH (6)
gear. Drive in FIFTH (5) gear (or, as you need to,
a lower gear).
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) (or the
manual transmission out of gear and the parking brake
applied) for a few minutes before turning the engine off.
If you do get the overheat warning, see ªEngine
Overheatingº in the Index.