1999 GMC C-SERIES brakes

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CAUTION:
To help avoid injury to you or others:

Never let passengers ride in a vehicle that is
being towed.

Never tow faster than safe or posted speeds.

Never tow with damaged parts not
fully secured.

Never get under your vehicle after it has
been lifted.

Always use separate safety chains on each
side when towing a vehicle.
If your vehicle uses dragfoilers, be sure to have the
dragfoiler
-to-cab mounting bracket bolts tightened after
your vehicle has been towed.
Here are specific towing instructions:
Towing Your Vehicle From the
Front (Front Wheels Off the Ground)
Before Towing
Block the rear wheels of the disabled vehicle. On
vehicles with air brakes, release the emergency brake
system by compressing the brake chamber springs as
outlined in this section. (Note: This is to prevent the
possibility of the emergency brake being applied
during towing.)
On vehicles with hydraulic brakes without an
electric/hydraulic parking brake, release the
parking brake fully by moving the lever to the
fully
-released position.
On vehicles equipped with an electric/hydraulic parking
brake option, remove the propshaft.
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After Towing
Block the rear wheels and install axle and propeller
shafts. Check for proper phasing of universal joints.
Apply the emergency brake system before disconnecting
from the towing vehicle. Check and fill the rear axle
with oil as required.
Towing Your Vehicle From the Front
(All Wheels On the Ground)
Your vehicle may be towed on all wheels provided the
steering is working. Remember that the power brakes
and power steering will not have power assist. Vehicles
with air brakes will not have brakes. There must be a
tow bar installed between the towing vehicle and the
disabled vehicle.
Before Towing
Block the wheels of the disabled vehicle. On vehicles
with air brakes, release the emergency brake system by
compressing the brake chamber springs as outlined in
this section. (Note: This is to prevent the possibility of
the emergency brake being applied during towing.)On vehicles with hydraulic brakes, release the
parking brake fully by moving the lever to the
fully
-released position.
On vehicles equipped with an electric/hydraulic parking
brake, remove the propshaft.
Disconnect the propshaft at the rear axle (forward axle
on tandem axle models). Secure the propshaft to the
frame or crossmember.
If there is damage or suspected damage to the axle(s),
remove the axle shafts. Cover the hub openings to
prevent the loss of lubricant or entry of dirt or
foreign objects.
After Towing
Block the rear wheels and install axle and propshafts.
Check for proper phasing of universal joints. Apply
the parking brake system before disconnecting from
the towing vehicle. Check and fill rear axle with oil
as required.
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5-15 Towing Your Vehicle From the Rear
(Rear Wheels Off the Ground)
Before Towing
Secure the steering wheel to maintain a straight
-ahead
position. Make certain that the front axle is not loaded
above the front axle Gross Axle Weight Rating (GAWR)
as indicated on the vehicle's Certification/Tire label.
After Towing
Block the rear wheels and release the steering. Apply the
parking brake system before disconnecting from the
towing vehicle.
Refer to the transmission shift label for
additional information.
Releasing Air-Operated Parking Brakes
If your vehicle has air brakes, you could have a special
towing problem. If your vehicle has to be towed because
you had a complete loss of air pressure from both
systems, the parking brakes may have applied. The tow
operator can release the brakes manually by using the
following steps. Then your vehicle can be towed with all
wheels or just the rear wheels on the ground.
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CAUTION:

Working on air brakes without first using
the release studs to compress the springs
can lead to injury. Never work on the air
brake chambers without first using the
release studs to compress the brake springs.

When the brake springs are manually
compressed, you will have no brakes.
Release your air
-operated parking brakes
manually only to tow the vehicle. Never
drive the vehicle with the brakes released.
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.
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5-17
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.6. Using a wrench, 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. Put the stud into the side of the chamber, and replace
the rubber cap.
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6-
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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
-6 Fuels in Foreign Countries (Gasoline Engines)
6
-7 Filling Your Tank
6
-8 Filling a Portable Fuel Container
6
-9 Checking Things Under the Hood
6
-11 Noise Control System
6
-13 Engine Oil (Gasoline Engine)
6
-17 Engine Oil (Caterpillar
Diesel Engine)
6
-17 Engine Air Cleaner/Filter
6
-18 Automatic Transmission Fluid
6
-19 Manual Transmission Fluid
6
-20 Rear Axle
6
-20 Rear Axle Shift Motor (Option)
6
-21 Radiator Pressure Cap (Gasoline Engines)
6
-22 Surge Tank Pressure Cap (Diesel Engines)
6
-22 Thermostat6
-23 Engine Coolant (Gasoline Engine)
6
-27 Engine Coolant (Caterpillar
Diesel Engine)
6
-28 Power Steering Fluid
6
-29 Windshield Washer Fluid
6
-30 Brakes
6
-36 Electric/Hydraulic Parking Brake Fluid
6
-42 Battery
6
-44 Other Service Items
6
-48 Tires
6
-59 Appearance Care
6
-59 Cleaning the Inside of Your Vehicle
6
-63 Cleaning the Outside Your Vehicle
6
-66 GM Vehicle Care/Appearance Materials
6
-67 Vehicle Identification Number (VIN)
6
-67 Service Parts Identification Label
6
-68 Electrical System
6
-74 Capacities and Specifications
6
-77 Air Conditioning Refrigerants
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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.
The brake master cylinder
reservoir is here. Refer to
the Maintenance Schedule
to determine when to check
your brake fluid.
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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, and don't use DOT
-5
silicone brake fluid.
NOTICE: (Continued)
NOTICE: (Continued)

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.
Four-Wheel Disc Brakes (Hydraulic Only)
Your vehicle has four-wheel disc brakes.
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.
Brake linings should always be replaced as complete
axle sets.
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