2007 GMC ENVOY brakes

Brakes
Brake Fluid
Your brake master
cylinder reservoir is
lled with DOT-3 brake
uid. SeeEngine
Compartment Overview
on page 390for the
location of the reservoir.
There are only two reasons why the brake uid
level in the reservoir might go down. The rst
is that the brake uid goes down to an acceptable
level during normal brake lining wear. When
new linings are put in, the uid level goes back
up. The other reason is that uid is leaking out of
the brake system. If it is, you should have your
brake system xed, since a leak means that
sooner or later your brakes will not work well, or
will not work at all.So, it is not a good idea to top off your brake uid.
Adding brake uid will not correct a leak. If you
add uid when your linings are worn, then you will
have too much uid when you get new brake
linings. You should add or remove brake uid, as
necessary, only when work is done on the
brake hydraulic system.
{CAUTION:
If you have too much brake uid, it can
spill on the engine. The uid will burn if
the engine is hot enough. You or others
could be burned, and your vehicle could
be damaged. Add brake uid only when
work is done on the brake hydraulic
system. See “Checking Brake Fluid” in
this section.
Refer to the Maintenance Schedule to determine
when to check your brake uid. SeeScheduled
Maintenance on page 507.
419

Checking Brake Fluid
You can check the brake uid without taking off
the cap.
Look at the brake uid
reservoir. The uid level
should be above
MIN. If it is not, have
your brake system
checked to see if there
is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN, but not over
the MAX mark.
What to Add
When you do need brake uid, use only DOT-3
brake uid. Use new brake uid from a sealed
container only. SeeRecommended Fluids and
Lubricants on page 517.
Always clean the brake uid reservoir cap and the
area around the cap before removing it. This will
help keep dirt from entering the reservoir.
{CAUTION:
With the wrong kind of uid in the brake
system, the brakes may not work well, or
they may not even work at all. This could
cause a crash. Always use the proper
brake uid.
Notice:
Using the wrong uid can badly damage
brake system parts. For example, just a few
drops of mineral-based oil, such as engine
oil, in the brake system can damage brake
system parts so badly that they will have to
be replaced. Do not let someone put in the
wrong kind of uid.
If you spill brake uid on your vehicle’s
painted surfaces, the paint nish can be
damaged. Be careful not to spill brake uid
on your vehicle. If you do, wash it off
immediately. SeeWashing Your Vehicle
on page 486.
420

Brake Wear
Your vehicle has four-wheel 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 may 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 may cause
a brake squeal when the brakes are rst applied or
lightly applied. This does not mean something is
wrong with your 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 GM torque
specications.
Brake linings should always be replaced as
complete axle sets.
Brake Pedal Travel
See your dealer 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 of brake trouble.
Brake Adjustment
Every time you make a brake stop, your disc
brakes adjust for wear.
421

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 GM brake parts. When you replace parts
of your braking system — for example, when your
brake linings wear down and you need new ones
put in — be sure you get new approved GM
replacement parts. If you do not, your brakes may
no longer work properly. For example, if someone
puts in brake linings that are wrong for your vehicle,
the balance between your 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 390for 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 your 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 423for tips on working
around a battery without getting hurt.
422

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/
transaxle, 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. SeeInation - Tire Pressure
on page 447.
Curb Weight:This means 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 349.
GAWR FRT:Gross Axle Weight Rating for the
front axle. SeeLoading Your Vehicle on page 349.
GAWR RR:Gross Axle Weight Rating for the
rear axle. SeeLoading Your Vehicle on page 349.
444

Your vehicle’s original equipment tires are listed
on the Tire and Loading Information Label.
This label is attached to the vehicle’s center pillar
(B-pillar). SeeLoading Your Vehicle on page 349,
for more information about the Tire and Loading
Information Label.
Different Size Tires and Wheels
If you add wheels or tires that are a different
size than your original equipment wheels and
tires, this may 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, 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 455and
Accessories and Modications on page 380
for additional information.
457

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.
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. 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, re-adjust or
remove the device if it is contacting your
vehicle, and do not spin your wheels. If
you do nd traction devices that will t,
install them on the rear tires.
461

Fuses Usage
5Driver’s Side High-Beam
Headlamp
6Driver’s Side Low-Beam
Headlamp
7 Windshield Wiper
8 Active Transfer Case
9 Windshield Washer
10 Powertrain Control Module B
11 Fog Lamps
12 Stoplamp
13 Cigarette Lighter
15 Electric Adjustable Pedals
16Truck Body Controller,
Ignition 1
17 Crank
18 Airbag
19 Trailer Electric Brake
20 Cooling Fan
21 Horn
22 Ignition E
23 Electronic Throttle ControlFuses Usage
24Instrument Panel Cluster,
Driver Information Center
25Automatic Shift Lock Control
System
26Transmission Control Module
Canister
27 Backup
28 Powertrain Control Module 1
29 Oxygen Sensor
30 Air Conditioning
31 Truck Body Controller 1
32 Trailer
33 Anti-lock Brakes (ABS)
34 Ignition A
35 Blower Motor
36 Blower
50 Passenger’s Side Trailer Turn
51 Driver’s Side Trailer Turn
52 Hazard Flashers
53 Headlamp Driver Module
54Air Injection Reactor (AIR)
Solenoid
495