brakes GMC SONOMA 2001 Owner's Guide

6-34
There are only two reasons why the brake fluid level in the
reservoir might go down. The first is that the brake fluid
goes down to an acceptable level during normal brake
lining wear. When new linings are put in, the fluid level
goes back up. The other reason is that fluid is leaking out
of the brake system. If it is, you should have your brake
system fixed, since a leak means that sooner or later your
brakes won't work well, or won't work at all.
So, it isn't a good idea to ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake fluid, it can spill on
the engine. The fluid will burn if the engine is hot
enough. You or others could be burned, and your
vehicle could be damaged. Add brake fluid only
when work is done on the brake hydraulic system.
See ªChecking Brake Fluidº in this section.
Refer to the Maintenance Schedule to determine when to
check your brake fluid. See ªPeriodic Maintenance
Inspectionsº in the Index.
Checking Brake Fluid
You can check the brake
fluid without taking off
the cap.
Just look at the brake fluid reservoir. The fluid level
should be above MIN. If it isn't, 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.

6-35
What to Add
When you do need brake fluid, use only DOT
-3 brake
fluid. Refer to ªRecommended Fluids and Lubricantsº
in the Index. Use new brake fluid from a sealed
container only.
Always clean the brake fluid 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 fluid in your brake
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brake fluid.
NOTICE:

Using the wrong fluid can badly damage
brake system parts. For example, just a few
drops of mineral
-based oil, such as engine
oil, in your brake system can damage brake
system parts so badly that they'll have to
be replaced. Don't let someone put in the
wrong kind of fluid.

If you spill brake fluid on your vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake fluid
on your vehicle. If you do, wash it off
immediately. See ªAppearance Careº in
the Index.

6-36 Brake Wear
If you have four-wheel drive, your vehicle has
four
-wheel disc brakes. If not, your vehicle has front
disc brakes and rear drum 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 firmly).
CAUTION:
The brake wear warning sound means that soon
your brakes won't 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 first 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 specifications.
If you have rear drum brakes, they don't have wear
indicators, but if you ever hear a rear brake rubbing
noise, have the rear brake linings inspected immediately.
Also, the rear brake drums should be removed and
inspected each time the tires are removed for rotation or
changing. When you have the front brake pads replaced,
have the rear brakes inspected, too.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7
of this manual under Part C ªPeriodic
Maintenance Inspections.º
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.

6-37 Brake Adjustment
Every time you make a brake stop, your disc brakes
adjust for wear.
If you don't have four
-wheel drive and your brake pedal
goes down farther than normal, your rear drum brakes
may need adjustment. Adjust them by backing up and
firmly applying the brakes a few times.
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 have to have new ones put in
-- be sure
you get new approved GM replacement parts. If you
don't, 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've come to expect can change in many
other ways if someone puts in the wrong replacement
brake parts.
Battery
Your new vehicle comes with a maintenance free
ACDelco
battery. When it's time for a new battery,
get one that has the replacement number shown on the
original battery's label. We recommend an ACDelco
battery. See ªEngine Compartment Overviewº in the
Index for 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.

6-66
Fuse/Circuit
BreakerUsage
3 Cruise Control, Body Controls
TBC, Cruise Module,
Cruise Switch
4 Gages, Body Controls TBC,
Instrument Panel Cluster,
B+ Power
5 Parking Lamps, Power Window
Switch, TBC, Ashtray Lamp
6 STR WHL ILLUM
7 Headlamp Switch, Body Controls
TBC, Headlamp Relay
8 Courtesy Lamps, Inadvertent
Power Relay
9 HVAC Control Head
10 Turn Signal
11 Instrument Panel Cluster,
Engine ControlsFuse/Circuit
BreakerUsage
12 Interior Illumination
13 Auxiliary Power
14 Power Locks
15 4WD Switch, Engine Control
(VCM, PCM, Transmission)
16 Supplemental Inflatable Restraint
17 Front Wiper
18 STR WHL RDO IGN
19 Radio Battery
20 AMPF
21 HVAC I, HVAC Control Head,
HVAC Devices
22 Anti
-Lock Brakes
23 Rear Wiper
24 Radio, Ignition

Short Trip/City Scheduled Maintenance
7-8
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.# Lubricate the front suspension, ball joints, steering
linkage, parking brake cable guides, propshaft splines,
universal joints and brake pedal springs.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under
ªPeriodic Maintenance Inspectionsº in Part C of
this schedule.
** Drive axle service. See ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use:

Check fluid level and add fluid as needed. If driving
in dusty areas or when towing a trailer, drain fluid
and refill every 15,000 miles (25 000 km).

If your vehicle has a locking differential, drain fluid
and refill at first engine oil change.

More frequent lubrication may be required for
heavy
-duty or off-road use.

Long Trip/Highway Scheduled Maintenance
7-30
The services shown in this schedule up to 100,000 miles
(166 000 km) should be performed after 100,000 miles
(166 000 km) at the same intervals. The services shown
at 150,000 miles (240 000 km) should be performed at
the same interval after 150,000 miles (240 000 km).
See ªOwner Checks and Servicesº and ªPeriodic
Maintenance Inspectionsº following.
Footnotes
 The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior to
the completion of the vehicle's useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the
maintenance be recorded.# Lubricate the front suspension, ball joints, steering
linkage, parking brake cable guides, propshaft splines,
universal joints and brake pedal springs.
+ A good time to check your brakes is during tire
rotation. See ªBrake System Inspectionº under
ªPeriodic Maintenance Inspectionsº in Part C of
this schedule.
** Drive axle service. See ªRecommended Fluids and
Lubricantsº in the Index for proper lubricant to use:

Check fluid level and add fluid as needed.

If your vehicle has a locking differential, drain fluid
and refill at first engine oil change.

7-49 Transfer Case and Front Axle
(Four-Wheel Drive) Inspection
Every 12 months or at engine oil change intervals, check
front axle and transfer case and add lubricant when
necessary. A fluid loss could indicate a problem; check
and have it repaired, if needed. Check vent hose at
transfer case for kinks and proper installation. More
frequent lubrication may be required on off
-road use.
Brake System Inspection
Inspect the complete system. Inspect brake lines and
hoses for proper hook
-up, binding, leaks, cracks,
chafing, etc. Inspect disc brake pads for wear and rotors
for surface condition. Also inspect drum brake linings
for wear and cracks. Inspect other brake parts, including
drums, wheel cylinders, calipers, parking brake, etc.
Check parking brake adjustment. You may need to have
your brakes inspected more often if your driving habits
or conditions result in frequent braking.

8-12
2001 GMC SERVICE PUBLICATIONS ORDERING INFORMATION
The following publications covering the operation and servicing of your vehicle can be purchased by filling out
the Service Publication Order Form in this book and mailing it in with your check, money order,
or credit card information to Helm, Incorporated (address below.)
CURRENT PUBLICATIONS FOR 2001 GMC
SERVICE MANUALS
Service Manuals have the diagnosis and repair information
on engines, transmission, axle, suspension, brakes,
electrical, steering, body, etc.
RETAIL SELL PRICE: $120.00
TRANSMISSION, TRANSAXLE, TRANSFER CASE
UNIT REPAIR MANUAL
This manual provides information on unit repair service
procedures, adjustments and specifications for the
2001 GM transmissions, transaxles and transfer cases.
RETAIL SELL PRICE: $50.00
SERVICE BULLETINS
Service Bulletins give technical service information needed
to knowledgeably service General Motors cars and trucks.
Each bulletin contains instructions to assist in the
diagnosis and service of your vehicle.OWNER'S INFORMATION
Owner publications are written directly for Owners and
intended to provide basic operational information about the
vehicle. The owner's manual will include the Maintenance
Schedule for all models.
In-Portfolio: Includes a Portfolio, Owner's Manual and
Warranty Booklet.
RETAIL SELL PRICE: $20.00
Without Portfolio: Owner's Manual only.
RETAIL SELL PRICE: $15.00
CURRENT & PAST MODEL ORDER FORMS
Service Publications are available for current and past
model GM vehicles. To request an order form, please
specify year and model name of the vehicle.
PLEASE COMPLETE THE ORDER FORM SHOWN ON
THE FOLLOWING PAGE AND MAIL TO:
Helm, Incorporated
P.O. Box 07130
Detroit, MI 48207OR ORDER TOLL FREE: 1-800-551-4123
Monday-Friday 8:00 AM ± 6:00 PM Eastern Time
Visit Helm, Inc. on the World Wide Web at: www.helminc.com
For Credit Card Orders Only (VISA±MasterCard±Discover)