1997 GMC SIERRA brake

Brakes
Brake Fluid
Your brake master cylinder
reservoir is here. It
is filled
with
DOT-3 brake fluid.
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 “top off’ 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.
I
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.
Refer to the Maintenance Schedule to determine when to
check your brake fluid. See “Periodic Maintenance
Inspections”
in the Index.
ProCarManuals.com

Checking Brake Fluid
You can check the brake fluid without taking off the cap.
Just look at the window on 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
MIN and below the top of
the window.
What to Add
When you do need brake fluid, use only DOT-3 brake
fluid
-- such as Delco Supreme ll@ (GM Part
No. 12377967). 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.
' A 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.
6-36
ProCarManuals.com

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 “Appearance Care” in
the Index.
Brake Wear
If you have a C 3500 HD model, it has four-wheel disc
brakes without wear indicators.
If you ever hear a brake
rubbing noise, have the brake linings inspected.
If your pickup is not a
C 3500 HD model, it has front
disc brakes and rear drum brakes. Disc brake pads
(except
C 3500 HD models) 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).
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.
ProCarManuals.com

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 torque wheel nuts in the
proper sequence
to GM 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. 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 “Brake System Inspection” in Section 7 of this manual
under Part
C “Periodic Maintenance Inspections.”
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.
If 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 modern 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.
ProCarManuals.com

I a 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.
I 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’’
in the Index. See
“Changing a
Flat Tire” in the Index for
more information.
Used Replacement Wheels
~
Putting a used wheel on your vehicle is dangerous.
You can’t know how it’s been used or how far it’s
been driven. It could fail suddenly and
cause an
new
GM original equipment wheel.
~ accident. If you have to replace a wheel, use a
Tire Chains
I NOTICE:
If your vehicle has dual wheels or P26975R16 size
tires, don’t use tire chains. They can damage
your
vehicle because there’s not enough clearance.
NOTICE: (Continued)
6-58
ProCarManuals.com

FuseKircuit Breaker
15
16
17
18
19
20
21
22
23
24
A
B
Usage
DRL Relay, Fog Lamp Relay
Front and Rear Turn Signals,
Back-up Lamps, BTSI Solenoid
Radio (Ignition)
LCWALNCM, ABS, Cruise Control
Radio (Battery)
PRNDL, Automatic Transmission, Speedometer, Check Gages
Warning Light
Variable Effort Steering
Not Used
Not Used
Front Axle, 4WD Indicator Lamp,
TP2 Relay (Gasoline Engine)
Power Door Lock, Six-Way Power
Seat, Keyless Entry Module
Power Windows
Underhood Fusemelay Center
The underhood fusehelay center is located in the rear
of the engine compartment near the brake fluid
reservoir. Move the retainer clips for the cover to
access the fuse block.
You can remove fuses with
a fuse extractor. The fuse
extractor
is mounted to the interior fuse block. To
remove fuses
if you don’t have a fuse extractor, hold the
end of the fuse between your thumb and index finger
and
pull straight out.
ProCarManuals.com

Name
ECM-B
RR DEFOG IGN-E
Usage
Fuel Pump, PCMNCM
Rear Window Defogger
Auxiliary Fan Relay Coil,
A/C
Compressor Relay, Hot Fuel
Module, Dual Tanks
Name
FUEL SOL
GLOW PLUG
HORN
AUX FAN
ECM-
1
NC
ENG-
1
LIGHTING
BATT
IGN-A
IGN-B ABS
BLOWER STOP/HAZ
Usage
Fuel Solenoid (Diesel Engine)
Glow plugs (Diesel Engine)
Horn, Underhood Lamps
Auxiliary Fan
Injectors,
PCMNCM
Air Conditioning
lgnition Switch,
EGR, Canister
Purge,
EVRV Idle Coast Solenoid,
Heated
02, Fuel Heater
(Diesel Engine), Water Sensor
(Diesel Engine)
Headlamp and Panel Dimmer
Switch,
Fog and Courtesy Fuses
Battery, Fuse Block Busbar
Ignition Switch
Ignition Switch
Anti-Lock Brake Module
Hi Blower Relay
Stoplamps
6-74
ProCarManuals.com

Maintenance Schedule
-
Short Trip/City Definition -- Gasoline Engines
Follow the Short TripKity Maintenance Schedule if any
one of these conditions is true for your vehicle:
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures
are below freezing.
driving in stop-and-go traffic).
off-road frequently.
Most trips include extensive idling (such as frequent
You operate your vehicle in dusty areas or
You frequently tow a trailer.
If the vehicle is used for delivery service, police, taxi
One of the reasons you should follow this schedule if you
operate
your vehicle under any of these conditions is that
these conditions cause engine
oil to break down soonel:
Short Trip/City Intervals -- Gasoline Engines
Every
3,000 Miles (5 000 km): Engine Oil and Filter
or other commercial application.
Change (or
3 months, whichever occurs first). Chassis
Lubrication (or
3 months, whichever occurs first). Drive
Axle Service (or
3 months, whichever occurs fmt).
Short Trip/City Intervals -- Gasoline Engines
Every 6,000 Miles (10
000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Shields and
Underhood Insulation Inspection (GVWR above
8,500 lbs. only). Front Wheel Bearing Repack (2WD
only) (or at each brake relining, whichever occurs first).
Every 30,000 Miles (50 000 km): Fuel Filter Replacement.
Every 50,000 Miles (83 000 km): Automatic
Transmission Service (vehicles over
8600 GVWR or
driven under severe conditions only).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel Tank, Cap and Lines
Inspection. Exhaust Gas Recirculation System
Inspection. Evaporative Control System Inspection.
Every 100,000 Miles (166 000 km): Spark Plug Wire
Inspection. Spark Plug Replacement. Positive
Crankcase Ventilation (PCV) Valve Inspection.
Every 150,000 Miles (240 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
These intervals only summarize maintenance services.
Be sure to follow the complete maintenance schedule
on the following pages.
ProCarManuals.com