wheel GMC C-SERIES 1999 Owner's Guide

yellowblue
5-36
CAUTION:
Never use oil or grease on studs or nuts. If you
do, the nuts might come loose. Your wheel could
fall off, causing a serious accident.
CAUTION:

There are many ways to be hurt badly, or
be killed, while you are trying to change a
truck tire and rim. Follow all of the safety
precautions on the truck jack and
other equipment.
CAUTION: (Continued)
CAUTION: (Continued)

If you try to put air back into a tire that has
run flat, or even a tire that was quite low on
air, without first finding out why it was low
or flat, the tire can have a sudden air
-out.
This could cause you to lose control of the
vehicle and have a serious crash. Don't
refill a flat or very low tire with air without
first having the tire taken off the wheel and
checked for damage.

Use a clip-on chuck and hose extension when you
add air to your tires. You'll need an accurate truck
tire pressure gage. Stand to one side and add the air.
Be sure you don't go over the top inflation pressure
for the tire.
ProCarManuals.com

yellowblue
5-37
CAUTION:
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to become loose
and even come off. This could lead to an accident.
Be sure to use the correct wheel nuts. If you have
to replace them, be sure to get new GM original
equipment wheel nuts.
Stop somewhere as soon as you can and have the
nuts tightened with a torque wrench.
See ªTightening the Wheel Nutsº in the Index for
the proper torque for your particular wheel.
NOTICE:
Improperly tightened wheel nuts can lead to
brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specification.
If You're Stuck: In Sand, Mud,
Ice or Snow
In order to free your vehicle when it is stuck, you will
need to spin the wheels, but you don't want to spin your
wheels too fast. The method known as ªrockingº can
help you get out when you're stuck, but you must
use caution.
CAUTION:
If you let your tires spin at high speed, they can
explode, and you or others could be injured. And,
the transmission or other parts of the vehicle can
overheat. That could cause an engine
compartment fire or other damage. When you're
stuck, spin the wheels as little as possible. Don't
spin the wheels above 35 mph (55 km/h) as shown
on the speedometer.
ProCarManuals.com

yellowblue
5-38
NOTICE:
Spinning your wheels can destroy parts of your
vehicle as well as the tires. If you spin the wheels
too fast while shifting your transmission back
and forth, you can destroy your transmission.
Rocking Your Vehicle To Get It Out
First, turn your steering wheel left and right. That will
clear the area around your front wheels. Then shift back
and forth between REVERSE (R) and a forward gear
(or with a manual transmission, between FIRST (1) or
SECOND (2) and REVERSE (R)), spinning the wheels
as little as possible. Release the accelerator pedal while
you shift, and press lightly on the accelerator pedal
when the transmission is in gear. By slowly spinning
your wheels in the forward and reverse directions, you
will cause a rocking motion that may free your vehicle.
If that doesn't get you out after a few tries, you may
need to be towed out. If you do need to be towed out,
see ªTowing Your Vehicleº in the Index.
ProCarManuals.com

yellowblue
6-32
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.
ProCarManuals.com

yellowblue
6-33 Four-Wheel and Six-Wheel Drum Brakes
(Air Only)
The brake drums should be removed and inspected each
time the tires are removed for rotation or changing.
When you have the front brakes replaced, have the rear
brakes inspected, too.
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 brakes adjust
for wear.
Air Brake Systems (If Equipped)
If you have air brakes, it is important to get rid of
moisture in the system. Moisture will damage your
system if it isn't removed daily.There are two ways to do this. One is automatic if your
air
-brake vehicle has the optional moisture ejector. If
your vehicle doesn't have that option, however, you
must drain the air reservoirs every day.
Drain them at full system
pressure. To be sure you're
at full pressure, check
your air pressure gage.
It should read at least
100 psi (692 kPa).
Moisture Ejector (Option)
If you have air brakes with a moisture ejector, the valve
automatically ejects moisture from the reserve tank
when the air compressor cycles.
ProCarManuals.com

yellowblue
6-39
ITEM NO. ITEM REMARKS
1 Brake Camshaft
, Brake Caliper
Rails (If Equipped)$One fitting each (apply sparingly). For caliper rails,
apply Aero Shell #5 Lubricant.
2 Steering Column Slip Joint* One fitting.
3 Steering Drag Link Ends One fitting at each end.
4 Steering Column U
-Joints One fitting each joint.
5 Pivot Points and Hinges Apply chassis lubricant.
6 Slack Adjuster
One fitting.
7 Brake Cam Roller Pins at interface
of pin and shoe
Apply engine oil.
8 Front Steering Knuckles One fitting each side, lower bushing (hand
-operated
grease gun only). Hand
-pack upper bearing.
9 Front Wheel Bearings Hand
-pack or lubricate.
10 Steering Tie Rod Ends One fitting each end.
11 Spring Slip Pads*
(Multi
-Leaf Only)Apply chassis lubricant.
12 Clutch Release Bearing* Cup or fitting.
13 Battery Terminal
(except ªSTº type)Keep coated with petroleum jelly.
14 Parking Brake Bell Crank*$ One fitting.
ProCarManuals.com

yellowblue
6-40
ITEM NO. ITEM REMARKS
15 Transmission Fill to level of filler plug.
16 Transmission
-Auto*
Check fluid level.
17 Propshaft Slip Joint One fitting each joint; lubricate with GM Part
No. 1051344 Wheel Bearing Lubricant.
18 Propshaft U
-Joints One fitting each joint (1480 and 1550 Series); lubricate
with GM Part No. 1051344 Wheel Bearing Lubricant. Two
fittings each joint (1610 Series and larger); lubricate with
GM Part No. 1051344 Wheel Bearing Lubricant.
19 Rear Wheel Bearing Hand
-pack or lubricate.
20 Rear Axle Fill to level of filler plug.
21 Parking Brake Clevis Pin$ Apply chassis lubricant.
22 Master Cylinder $ Fill to 1/4, (6 mm) below opening.
23 Parking Brake Lever Pivot*$ Apply chassis lubricant.
* Applies to some vehicles.
 Applies to air brakes only.

Refer to Allison Transmission Operator's Manual.
$ Applies to hydraulic brakes only.
ProCarManuals.com

yellowblue
6-41
Tandem Axle ModelsITEM
NO.ITEM REMARKS
1 Brake Camshafts One fitting each.
2 Propshaft U
-Joint One fitting each joint
(1480 and 1550 Series).
Lubricate with GM Part
No. 1051344, Wheel
Bearing Lubricant.
4 Brake Shoe
Roller PinsApply engine oil at pin
to shoe joint only.
5 Rear Spring Pin One fitting each side.
6 Wheel Bearings Hand
-pack or lubricate.
7 Rear Axles Fill to level of filler plug.
8 Propshaft Slip
JointTwo fittings each side.
Lubricate with GM Part
No. 1051344 Wheel
Bearing Lubricant.
ProCarManuals.com

yellowblue
6-47 Front Wheel Bearings with Oil-Filled Hubs
If your vehicle has oil-filled
hubs, occasionally check to
see if they have enough oil.
You can tell by looking into
the sight glass to see if there
is oil there.
If there isn't, clean the rubber fill plug in the center of
the glass, and then remove it. Be careful not to allow
any dirt or water to get into the oil. Add enough of the
recommended oil to bring it up to the level mark that
you'll see on the glass.
Refer to your Maintenance Schedule for the proper oil
to use.
When you fill the hub, check the glass again after
driving a short distance. It takes a while for the oil to
flow through the system, and you may find that you
have to add a little more to fill it to the proper level.
Air Conditioning System
Every now and then, have your dealership check your
air conditioning system to be sure it has not lost any
cooling ability. If you think the system is not working
properly, have your GM Truck dealer check it out as
soon as possible.
The air conditioning won't work when the temperature
outside is below 40
F (4
C).
NOTICE:
If your vehicle is equipped with factory air
conditioning, the system is charged with the
R
-134a refrigerant. Servicing of the air
conditioning system should be performed by a
trained service technician.
ProCarManuals.com

yellowblue
6-50 Rims and Wheels
Rims and wheels are stamped with a maximum load and
cold inflation rating. Be sure you don't exceed these limits.
Dual Tire Operation
When the vehicle is new, or whenever a wheel, wheel
bolt or wheel nut is replaced, check the wheel nut torque
as indicated:
If your vehicle has stud piloted or hub piloted wheels,
tighten the wheel stud nuts to the specified torque values
at 100 miles (160 km), 500 miles (800 km) and
1,000 miles (1 600 km) and then every 1,000 miles
(1 600 km) thereafter.
For proper torque, see ªWheel Nut Torqueº in the Index.
The outer tire on a dual wheel setup generally wears
faster than the inner tire. Your tires will wear more
evenly and last longer if you rotate the tires periodically.
If you're going to be doing a lot of driving on
high
-crown roads, you can reduce tire wear by adding
5 psi (35 kPa) to the tire pressure in the outer tires. Be
sure to return to the recommended pressures when no
longer driving under those conditions. See ªChanging a
Flat Tireº in the Index for more information.
CAUTION:
If you operate your vehicle with a tire that is
badly underinflated, the tire can overheat. An
overheated tire can lose air suddenly or catch
fire. You or others could be injured. Be sure
all tires (including the spare, if any) are
properly inflated.
ProCarManuals.com