2008 GMC SIERRA brake

Brake Wear
Your vehicle has front disc brakes and could have rear
drum brakes or rear disc brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads
are worn and new pads are needed. The sound can
come and go or be heard all the time your vehicle is
moving, except when you are pushing on the brake
pedal rmly.
{CAUTION:
The brake wear warning sound means that
soon the brakes will not work well. That could
lead to an accident. When you hear the brake
wear warning sound, have your vehicle
serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can cause a brake
squeal when the brakes are rst applied or lightly
applied. This does not mean something is wrong with
the brakes.Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to torque specications in
Capacities and Specifications on page 5-130.
If you have rear drum brakes, they do not have wear
indicators, but if you ever hear a rear brake rubbing
noise, have the rear brake linings inspected immediately.
Rear brake drums should be removed and inspected
each time the tires are removed for rotation or changing.
Drum brakes have an inspection hole to inspect lining
wear during scheduled maintenance. When you have
the front brake pads replaced, have the rear brakes
inspected, too.
Brake linings should always be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer/retailer if the brake pedal does not
return to normal height, or if there is a rapid increase in
pedal travel. This could be a sign that brake service
might be required.
Brake Adjustment
Every time you make a brake stop, the brakes adjust
for wear.
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Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together if
the vehicle is to have really good braking. Your vehicle
was designed and tested with top-quality brake parts.
When you replace parts of the braking system — for
example, when the brake linings wear down and you
need new ones put in — be sure you get new approved
replacement parts. If you do not, the brakes might not
work properly. For example, if someone puts in brake
linings that are wrong for your vehicle, the balance
between the front and rear brakes can change — for the
worse. The braking performance you have come to
expect can change in many other ways if someone puts
in the wrong replacement brake parts.
Battery
Your vehicle has a maintenance free battery
(or batteries). When it is time for a new battery, see
your dealer/retailer for one that has the replacement
number shown on the original battery’s label. See
Engine Compartment Overview on page 5-14for
battery location.
Warning:Battery posts, terminals, and related
accessories contain lead and lead compounds,
chemicals known to the State of California to cause
cancer and reproductive harm. Wash hands after
handling.
Vehicle Storage
{CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
are not careful. SeeJump Starting on
page 5-46for tips on working around a battery
without getting hurt.
Infrequent Usage: If you drive your vehicle infrequently,
remove the black, negative (−) cable from the battery.
This will help keep the battery from running down.
Extended Storage: For extended storage of your vehicle,
remove the black, negative (−) cable from the battery or
use a battery trickle charger. This will help maintain the
charge of the battery over an extended period of time.
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3. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles are not touching
each other. If they are, it could cause an unwanted
ground connection. You would not be able to start
your vehicle, and the bad grounding could damage
the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake rmly on both vehicles involved in
the jump start procedure. Put the automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake.
If you have a four-wheel-drive vehicle, be sure the
transfer case is in a drive gear, not in NEUTRAL.
Notice:If you leave your radio or other accessories
on during the jump starting procedure, they could
be damaged. The repairs would not be covered
by your warranty. Always turn off your radio and
other accessories when jump starting your vehicle.
4. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlets. Turn off the
radio and all the lamps that are not needed. This will
avoid sparks and help save both batteries. And it
could save the radio!5. Open the hood on the other vehicle and locate the
positive (+) and negative (−) terminal locations on
that vehicle.
The positive (+) terminal, is located under a red
plastic cover at the positive battery post. To uncover
the positive (+) terminal, open the red plastic cover.
The remote negative (−) terminal is a stud located
on the right front passenger side of the engine,
where the negative battery cable attaches.
SeeEngine Compartment Overview on page 5-14
5-47

Tire Terminology and Denitions
Air Pressure:The amount of air inside the
tire pressing outward on each square inch of the
tire. Air pressure is expressed in pounds per
square inch (psi) or kilopascal (kPa).
Accessory Weight
:This means the combined
weight of optional accessories. Some examples of
optional accessories are, automatic transmission,
power steering, power brakes, power windows,
power seats, and air conditioning.
Aspect Ratio
:The relationship of a tire’s height
to its width.
Belt
:A rubber coated layer of cords that is
located between the plies and the tread. Cords
may be made from steel or other reinforcing
materials.
Bead
:The tire bead contains steel wires wrapped
by steel cords that hold the tire onto the rim.
Bias Ply Tire
:A pneumatic tire in which the plies
are laid at alternate angles less than 90 degrees
to the centerline of the tread.Cold Tire Pressure
:The amount of air pressure
in a tire, measured in pounds per square inch
(psi) or kilopascals (kPa) before a tire has built up
heat from driving. SeeInflation - Tire Pressure
on page 5-74.
Curb Weight
:The weight of a motor vehicle with
standard and optional equipment including the
maximum capacity of fuel, oil, and coolant, but
without passengers and cargo.
DOT Markings
:A code molded into the sidewall
of a tire signifying that the tire is in compliance
with the U.S. Department of Transportation (DOT)
motor vehicle safety standards. The DOT code
includes the Tire Identication Number (TIN),
an alphanumeric designator which can also identify
the tire manufacturer, production plant, brand, and
date of production.
GVWR
:Gross Vehicle Weight Rating. See
Loading Your Vehicle on page 4-36.
GAWR FRT
:Gross Axle Weight Rating for
the front axle. SeeLoading Your Vehicle
on page 4-36.
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TPMS Sensor Matching Process
Each TPMS sensor has a unique identication code.
Any time you rotate your vehicle’s tires or replace one or
more of the TPMS sensors, the identication codes will
need to be matched to the new tire/wheel position. The
sensors are matched to the tire/wheel positions in the
following order: driver side front tire, passenger side front
tire, passenger side rear tire, and driver side rear tire
using a TPMS diagnostic tool. See your dealer/retailer
for service.
The TPMS sensors can also be matched to each
tire/wheel position by increasing or decreasing the tire’s
air pressure. If increasing the tire’s air pressure, do not
exceed the maximum ination pressure indicated on the
tire’s sidewall.
To decrease air-pressure out of a tire you can use the
pointed end of the valve cap, a pencil-style air pressure
gage, or a key.
You have two minutes to match the rst tire/wheel
position, and ve minutes overall to match all
four tire/wheel positions. If it takes longer than
two minutes, to match the rst tire and wheel, or more
than ve minutes to match all four tire and wheel
positions the matching process stops and you need to
start over.The TPMS sensor matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the
engine off.
3. Press the Remote Keyless Entry (RKE) transmitter’s
LOCK and UNLOCK buttons at the same time for
approximately ve seconds. The horn sounds twice
to signal the receiver is in relearn mode and TIRE
LEARNING ACTIVE message displays on the DIC
screen.
If your vehicle does not have RKE, press the Driver
Information Center (DIC) vehicle information
button until the PRESS
VTO RELEARN TIRE
POSITIONS message displays. The horn sounds
twice to signal the receiver is in relearn mode
and TIRE LEARNING ACTIVE message displays
on the DIC screen.
If your vehicle does not have RKE or DIC buttons,
press the trip odometer reset stem located on the
instrument panel cluster until the PRESS
VTO
RELEARN TIRE POSITIONS message displays.
The horn sounds twice to signal the receiver is in
relearn mode and TIRE LEARNING ACTIVE
message displays on the DIC screen.
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When It Is Time for New Tires
Various factors, such as maintenance, temperatures,
driving speeds, vehicle loading, and road conditions,
inuence when you need new tires.
One way to tell when it is
time for new tires is to
check the treadwear
indicators, which appear
when your tires have only
1/16 inch (1.6 mm) or less
of tread remaining. Some
commercial truck tires may
not have treadwear
indicators.
You need new tires if any of the following statements
are true:
You can see the indicators at three or more places
around the tire.
You can see cord or fabric showing through the
tire’s rubber.
The tread or sidewall is cracked, cut, or snagged
deep enough to show cord or fabric.
The tire has a bump, bulge, or split.
The tire has a puncture, cut, or other damage that
cannot be repaired well because of the size or
location of the damage.
The rubber in tires degrades over time, even if they are
not being used. This is also true for the spare tire, if
your vehicle has one. Multiple conditions affect how fast
this aging takes place, including temperatures, loading
conditions, and ination pressure maintenance. With
proper care and maintenance tires will typically wear out
before they degrade due to age. If you are unsure about
the need to replace your tires as they get older, consult
the tire manufacturer for more information.
Buying New Tires
GM has developed and matched specic tires for your
vehicle. The original equipment tires installed on your
vehicle, when it was new, were designed to meet General
Motors Tire Performance Criteria Specication
(TPC spec) system rating. If you need replacement tires,
GM strongly recommends that you get tires with the same
TPC Spec rating. This way, your vehicle will continue to
have tires that are designed to give the same
performance and vehicle safety, during normal use, as
the original tires.
GM’s exclusive TPC Spec system considers over a
dozen critical specications that impact the overall
performance of your vehicle, including brake system
performance, ride and handling, traction control, and tire
pressure monitoring performance. GM’s TPC Spec
5-84

Different Size Tires and Wheels
If you add wheels or tires that are a different size than
your original equipment wheels and tires, this could
affect the way your vehicle performs, including its
braking, ride and handling characteristics, stability, and
resistance to rollover. Additionally, if your vehicle has
electronic systems such as anti-lock brakes, rollover
airbags, traction control, and electronic stability control,
the performance of these systems can be affected.
{CAUTION:
If you add different sized wheels, your vehicle
may not provide an acceptable level of
performance and safety if tires not
recommended for those wheels are selected.
You may increase the chance that you will
crash and suffer serious injury. Only use GM
specic wheel and tire systems developed for
your vehicle, and have them properly installed
by a GM certied technician.
SeeBuying New Tires on page 5-84andAccessories
and Modifications on page 5-4for additional information.
Uniform Tire Quality Grading
Quality grades can be found where applicable on
the tire sidewall between tread shoulder and
maximum section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration (NHTSA), which
grades tires by treadwear, traction, and
temperature performance. This applies only to
vehicles sold in the United States. The grades are
molded on the sidewalls of most passenger car
tires. The Uniform Tire Quality Grading (UTQG)
system does not apply to deep tread, winter-type
snow tires, space-saver, or temporary use
spare tires, tires with nominal rim diameters of
10 to 12 inches (25 to 30 cm), or to some
limited-production tires.
While the tires available on General Motors
passenger cars and light trucks may vary with
respect to these grades, they must also conform
to federal safety requirements and additional
General Motors Tire Performance Criteria (TPC)
standards.
5-86

{CAUTION:
Using the wrong replacement wheels, wheel
bolts, or wheel nuts on your vehicle can be
dangerous. It could affect the braking and
handling of your vehicle, make your tires lose
air and make you lose control. You could have
a collision in which you or others could be
injured. Always use the correct wheel, wheel
bolts, and wheel nuts for replacement.
Notice:The wrong wheel can also cause problems
with bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper height,
vehicle ground clearance, and tire or tire chain
clearance to the body and chassis.
Whenever a wheel, wheel bolt or wheel nut is
replaced on a dual wheel setup, check the wheel
nut torque after 100, 1,000 and 6,000 miles
(160, 1 600 and 10 000 km) of driving. For proper
torque, see “Wheel Nut Torque” underCapacities and
Specifications on page 5-130.
SeeChanging a Flat Tire on page 5-92for more
information.
Used Replacement Wheels
{CAUTION:
Putting a used wheel on your vehicle is
dangerous. You cannot know how it has been
used or how far it has been driven. It could fail
suddenly and cause a crash. If you have to
replace a wheel, use a new GM original
equipment wheel.
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