brake CHEVROLET C/K 2003 Repair Manual

5-16 Releasing Air-Operated Parking Brakes
(If Equipped)
If your vehicle has air brakes, you could have a special
towing problem. If your vehicle has to be towed because
of a complete loss of air pressure from both systems, the
parking brakes will have automatically engaged. The
tow operator can release the brakes manually by using
the following steps. Then your vehicle can be towed
with all wheels or only the rear wheels on the ground.
1. Block the wheels of the vehicle.
2. Remove the release stud and nut from the side of the
brake chamber. Some chambers have studs which are
visible at all times.
3. Remove the rubber
cap from the rear of
the chamber.
4. Put the release stud, nut and flat washer into
the chamber.
5. Turn the stud clockwise a quarter of a turn.

5-17
6. Turn the stud nut
clockwise several turns
to release the brakes.
Follow the same
procedure to release the
other brake.
7. At the repair facility, apply air pressure of at least
70 psi (480 kPa) to the brake chambers, either from
an external air supply or the vehicle's air system.
8. Turn the stud nut counterclockwise several turns.
Remove the stud from the chamber.
9. Replace the stud and washer and tighten the nut
into the side of the chamber.
10. Replace the rubber cap.Engine Overheating
You will find a coolant temperature warning gage on
your vehicle's instrument panel, as well as a low coolant
warning light. Your vehicle also has a check gages
warning light on the instrument panel.

5-26
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the clutch is not fully engaged. This
improves fuel economy and reduces fan noise. Under
heavy vehicle loading, trailer towing and/or high outside
temperatures, the fan speed increases when the clutch
engages. So you may hear an increase in fan noise.
This is normal and should not be mistaken as the
transmission slipping or making extra shifts. It is merely
the cooling system functioning properly. The fan will
slow down when additional cooling is not required and
the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
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'd 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.
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place and turn on your
hazard warning flashers. The next part tells you what
to do.

6-
6-1
Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-4 Fuel (Gasoline Engine)
6
-5 Diesel Fuel Requirements and Fuel System
6
-15 Fuels in Foreign Countries (Gasoline Engines)
6
-15 Filling Your Tank
6
-17 Filling a Portable Fuel Container
6
-18 Checking Things Under the Hood
6
-20 Noise Control System
6
-21 Engine Oil (Gasoline Engines)
6
-27 Engine Oil (Caterpillar
Diesel Engines)
6
-27 Engine Oil (DURAMAX Diesel)
6
-30 Engine Air Cleaner/Filter
6
-32 Automatic Transmission Fluid
6
-32 Manual Transmission Fluid
6
-34 Rear Axle
6
-34 Rear Axle Shift Motor (Option)
6
-35 Engine Coolant
6
-38 Engine Coolant (Caterpillar
Diesel Engine)6
-38 Surge Tank Pressure Cap
6
-39 Power Steering Fluid
6
-40 Windshield Washer Fluid
6
-41 Brakes
6
-52 Battery
6
-54 Other Service Items
6
-58 Tires
6
-67 Appearance Care
6
-68 Cleaning the Inside of Your Vehicle
6
-71 Cleaning the Outside Your Vehicle
6
-75 GM Vehicle Care/Appearance Materials
6
-76 Vehicle Identification Number (VIN)
6
-76 Service Statement
6
-77 Service Parts Identification Label
6
-77 Electrical System
6
-86 Capacities and Specifications
6
-90 Normal Maintenance Replacement Parts

6-10
To drain water, do the following:
1. Stop and park the vehicle in a safe place. Turn off
the engine and apply the parking brake.
2. Remove the fuel cap.
3. Place a fuel
-resistant container under the fuel filter.
The filter drain valve is located on the bottom of the
fuel filter. The fuel filter is located in the engine
compartment on the passenger's side of the vehicle,
or on the driver's side frame rail near the engine.
4. Open the drain valve by
turning two to three
turns. When fuel
empties from the valve,
all the water has been
drained. Close the valve
hand tight.5. Remove the fuel
-resistant container and properly
dispose of the contaminated fuel. To find out how to
properly dispose of contaminated diesel fuel, see
ªWhat to Do with Used Oilº in the ªEngine Oil
(Diesel Engines)º part, later in this section.
6. Install the fuel cap.
7. Start the engine and let it run for a few minutes.
If the engine stalls, the fuel system may need to be
primed. While draining the water from the fuel filter,
air may enter the fuel system. If air has entered the
fuel system the fuel system will need to be primed.
Refer to ªFuel Primingº later in this section.
If the water in fuel indicator comes on again after
driving a short distance or the engine runs rough or
stalls, a large amount of water has probably been
pumped into the fuel tank. The fuel tank should
be purged.
Fuel Priming
In order for the DURAMAX diesel engine fuel system
to work properly, the fuel lines must be full of fuel and
contain no air. If air gets into the fuel lines, it will be
necessary to prime the fuel lines to eliminate air before
operating the vehicle.

6-14 Fuel Filter Replacement (Diesel Engines)
If you want to change the fuel filter yourself, here's how
to do it:
CAUTION:
Diesel fuel is flammable. It could start a fire if
something ignites it, and you could be burned.
Don't let it get on hot engine parts, and keep
matches or other ignition sources away.
First, drain any water from the filter following the
procedure for draining water listed previously.
Your vehicle's engine should be off until the end of
this procedure.
The fuel filter is located in the engine compartment on
the passenger's side of the vehicle, or on the driver's
side frame rail in front of the fuel tank.
1. Apply the parking brake.
2. Unplug the water sensor
wire connected to the
fuel filter and unscrew
the filter element.
3. Remove the filter element. If there is any dirt on the
filter sealing surface, clean it off. Remove and reuse
the water sensor float switch located on the bottom
of the fuel filter.
4. Install the new filter element.
5. Reinstall and tighten the filter container and
reconnect the water sensor wire to the filter.
6. Use the fuel filter priming procedure earlier in this
section to prime the fuel filter.
7. Tighten the air bleed valve by turning it clockwise
until hand tight.
8. Start your engine and let it idle for five minutes.
Check your fuel filter and air bleed valve for leaks.

6-18
Checking Things Under the Hood
CAUTION:
Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.
Hood Latches
To tilt the hood forward, pull back and up on each of the
hood latches, located above the wheel wells on both
sides of the vehicle.

6-39
Power Steering Fluid
See your Maintenance Schedule for when to check your
power steering fluid.
How To Check Power Steering Fluid
Check your power steering fluid only when the engine is
warm. If the engine isn't warm, you probably won't get
an accurate reading.
If the fluid level is
between the MIN and
MAX marks, you have
enough. If you need
fluid, add only enough
of the proper fluid to
bring it into view in
the sight glass.If your power steering fluid level is low, this can cause
the BRAKE or service brake soon warning lights to
come on. If either light remains on after you have added
power steering fluid to the proper level, then shut off the
engine for 10 seconds. This should reset the brake
warning lights. If one or both lights stay on though, see
ªHydraulic Brake Warning Lightsº in the Index.
What to Use
To determine what kind of fluid to use, see
ªRecommended Fluids and Lubricantsº in the Index.
NOTICE:
When adding power steering fluid or making a
complete fluid change, always use the proper
fluid. Failure to use the proper fluid can cause
leaks and damage hoses and seals.

6-41
NOTICE:

When using concentrated washer fluid,
follow the manufacturer's instructions for
adding water.

Don't mix water with ready
-to-use washer
fluid. Water can cause the solution to freeze
and damage your washer fluid tank and
other parts of the washer system. Also,
water doesn't clean as well as washer fluid.

Fill your washer fluid tank only
three
-quarters full when it's very cold.
This allows for expansion if freezing occurs,
which could damage the tank if it is
completely full.

Don't use engine coolant (antifreeze) in
your windshield washer. It can damage
your washer system and paint.
Brakes
Brake Fluid
If your vehicle has hydraulic brakes, there's a brake
master cylinder. Refer to the Maintenance Schedule to
determine when to check your brake fluid.
CAUTION:
Don't add brake fluid before you check the level.
If you do, you could get too much brake fluid.
Brake fluid could spill on the hot engine and it
can catch fire. You could be burned and your
vehicle could be damaged. See ªChecking Brake
Fluidº in this section.

6-42
Checking Brake Fluid (Hydro Max System)
Apply the brake pedal several times with the ignition
off. Then clean one of the reservoir caps and the area
around the cap, and remove it. The fluid level should be
even with the bottom ring of the filler opening.
The Hydro Max
brake fluid reservoir
is located in the
engine compartment
on the driver's side
of the vehicle.
If it's low, add enough fluid to fill the reservoir to the
proper level.Checking Brake Fluid (Hydro Boost System)
Apply the brake pedal several times with the ignition
off. Clean the cover and the side of the reservoir.
Check to see if the fluid level inside the reservoir falls
within the MIN/MAX level indicator on the side of
the reservoir.
The Hydro Boost
brake fluid reservoir
is located in the
engine compartment
on the driver's side
of the vehicle.
If it's low, add enough fluid to fill the reservoir to the
proper level.