brake GMC ACADIA 2007 Workshop Manual

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.
When it is time for a new battery, get one that has
the replacement number shown on the original
battery’s label. We recommend an ACDelco
®
replacement battery. SeeEngine Compartment
Overview on page 396for 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
If you are not going to drive your vehicle for
25 days or more, remove the black, negative (−)
cable from the battery. This will help keep the
battery from running down.
{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 425for tips on working
around a battery without getting hurt.
424

Jump Starting
If your vehicle’s battery has run down, you may
want to use another vehicle and some jumper
cables to start your vehicle. Be sure to use
the following steps to do it safely.
{CAUTION:
Batteries can hurt you. They can be
dangerous because:
They contain acid that can burn you.
They contain gas that can explode or
ignite.
They contain enough electricity to
burn you.
If you do not follow these steps exactly,
some or all of these things can hurt you.
Notice:Ignoring these steps could result in
costly damage to your vehicle that would
not be covered by your warranty.Trying to start your vehicle by pushing or
pulling it will not work, and it could damage
your vehicle.
1. Check the other vehicle. It must have a
12-volt battery with a negative ground system.
Notice:If the other vehicle’s system is not
a 12-volt system with a negative ground, both
vehicles can be damaged. Only use vehicles
with 12-volt systems with negative grounds to
jump start your vehicle.
2. 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 a ground connection you do not
want. 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
an 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 not in NEUTRAL.
425

(B) Tire Width:The three-digit number indicates
the tire section width in millimeters from sidewall
to sidewall.
(C) Aspect Ratio:A two-digit number that
indicates the tire height-to-width measurements.
For example, if the tire size aspect ratio is 60,
as shown in item C of the illustration, it would
mean that the tire’s sidewall is 60 percent as high
as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire.
The letter R means radial ply construction;
the letter D means diagonal or bias ply
construction; and the letter B means belted-bias
ply construction.
(E) Rim Diameter:Diameter of the wheel in
inches.
(F) Service Description:These characters
represent the load range and speed rating of the
tire. The load index represents the load carry
capacity a tire is certied to carry. The load index
can range from 1 to 279. The speed rating is
the maximum speed a tire is certied to carry a
load. Speed ratings range from A to Z.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.
439

The TPMS sensor matching process is outlined
below:
1. Set the parking brake.
2. Turn the ignition switch to ON with the
engine off.
3. Using the DIC, press the vehicle information
button until the PRESS
VTO RELEARN TIRE
POSITIONS message displays. If your vehicle
does not have the DIC buttons, press the trip
odometer reset stem located on the instrument
panel cluster until the RELEARN TIRE
POSITIONS message displays.
4. If your vehicle has the DIC buttons, press the
set/reset button. The horn sounds twice to
indicate the TPMS receiver is ready, and the
TIRE LEARNING ACTIVE message
displays. If your vehicle does not have the
DIC buttons, press and hold the trip odometer
reset stem until the horn chirps twice and
the TIRE LEARNING ACTIVE message
is displayed.
5. Start with the driver side front tire. The driver
side front turn signal lamp is on.6. Remove the valve cap from the valve stem.
Activate the TPMS sensor by increasing
or decreasing the tire’s air pressure for
ve seconds, or until a horn chirp sounds.
The horn chirp, which may take up to
30 seconds to sound, conrms that the sensor
identication code has been matched to this
tire and wheel position.
7. Proceed to the passenger side front tire.
The passenger side front turn signal lamp is on.
Repeat the procedure in Step 6.
8. Proceed to the passenger side rear tire.
The passenger side rear turn signal lamp is on.
Repeat the procedure in Step 6.
9. Proceed to the driver side rear tire. The driver
side rear turn signal lamp is on. Repeat the
procedure in Step 6. Instead of a single horn
chirp a double horn chirp signals the TPMS
sensor has been matched to this tire and wheel
position and the matching process is no longer
active.
10. Turn the ignition switch to OFF.
11. Set all four tires to the recommended air
pressure level as indicated on the Tire and
Loading Information label.
12. Put the valve caps back on the valve stems.
447

When It Is Time for New Tires
One way to tell when it
is time for new tires is
to check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of tread
remaining.
You need a new tire 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.
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 number is molded
onto the tire’s sidewall by the tire manufacturer.
If the tires have an all-season tread design,
the TPC spec number will be followed by an
MS for mud and snow. SeeTire Sidewall Labeling
on page 436for additional information.
450

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 450and
Accessories and Modifications on page 385
for additional information.
452

Each new wheel should have the same
load-carrying capacity, diameter, width, offset
and be mounted the same way as the one
it replaces.
If you need to replace any of your wheels, wheel
bolts, or wheel nuts, replace them only with
new GM original equipment parts. This way,
you will be sure to have the right wheel, wheel
bolts, and wheel nuts for your vehicle.
{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.
SeeChanging a Flat Tire on page 458for 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.
455

Tire Chains
{CAUTION:
Do not use tire chains. There is not
enough clearance. Tire chains used on a
vehicle without the proper amount of
clearance can cause damage to the
brakes, suspension or other vehicle parts.
The area damaged by the tire chains
could cause you to lose control of your
vehicle and you or others may be injured
in a crash.
CAUTION: (Continued)
CAUTION: (Continued)
Use another type of traction device only if
its manufacturer recommends it for use
on your vehicle and tire size combination
and road conditions. Follow that
manufacturer’s instructions. To help avoid
damage to your vehicle, drive slowly,
readjust or remove the device if it is
contacting your vehicle, and do not spin
your vehicle’s wheels. If you do nd
traction devices that will t, install them
on the front tires.
456

If a Tire Goes Flat
It is unusual for a tire to blowout while you are
driving, especially if you maintain your vehicle’s
tires properly. If air goes out of a tire, it is
much more likely to leak out slowly. But if you
should ever have a blowout, here are a few tips
about what to expect and what to do:
If a front tire fails, the at tire will create a drag
that pulls the vehicle toward that side. Take your
foot off the accelerator pedal and grip the
steering wheel rmly. Steer to maintain lane
position, and then gently brake to a stop well out
of the traffic lane.
A rear blowout, particularly on a curve, acts much
like a skid and may require the same correction
you would use in a skid. In any rear blowout
remove your foot from the accelerator pedal. Get
the vehicle under control by steering the way
you want the vehicle to go. It may be very bumpy
and noisy, but you can still steer. Gently brake
to a stop, well off the road if possible.{CAUTION:
Lifting a vehicle and getting under it to do
maintenance or repairs is dangerous
without the appropriate safety equipment
and training. The jack provided with your
vehicle is designed only for changing a
at tire. If it is used for anything else, you
or others could be badly injured or killed
if the vehicle slips off the jack. Use the
jack provided with your vehicle only for
changing a at tire.
If a tire goes at, the next part shows how to use the
jacking equipment to change a at tire safely.
457

Changing a Flat Tire
If a tire goes at, avoid further tire and wheel
damage by driving slowly to a level place. Turn on
your vehicle’s hazard warning ashers. See
Hazard Warning Flashers on page 172for more
information.
{CAUTION:
Changing a tire can be dangerous. The
vehicle can slip off the jack and roll over
or fall on you or other people. You and
they could be badly injured or even killed.
Find a level place to change your tire.
To help prevent the vehicle from moving:
1. Set the parking brake rmly.
2. Put the shift lever in PARK (P).
CAUTION: (Continued)
CAUTION: (Continued)
3. Turn off the engine and do not restart
while the vehicle is raised.
4. Do not allow passengers to remain in
the vehicle.
To be even more certain the vehicle will
not move, you should put blocks at the
front and rear of the tire farthest away
from the one being changed. That would
be the tire, on the other side, at the
opposite end of the vehicle.
When your vehicle has a at tire, use the following
example as a guide to assist you in the placement
of wheel blocks.
458