1999 GMC C-SERIES brake

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7-16 90,000 Miles (150 000 km) (Continued)

Clutch pedal free travel service. (10)

Air brake automatic slack adjuster service (or every
500 hours, whichever occurs first). (40)

Clean air brake application valve (or every 3 months,
or every 300 hours, whichever occurs first);
lubricate linkage.
93,000 Miles (155 000 km)

Engine oil and filter service. (3)(9)

Check fluid levels (or every 3 months, whichever
occurs first). (1)(2)(6)
96,000 Miles (160 000 km)

Engine oil and filter service. (3)(9)

Check fluid levels (or every 3 months, whichever
occurs first). (1)(2)(6)

Chassis lubrication service (or every 6 months,
whichever occurs first). (12)

Lubricate door hinge pins and rollers with engine oil.

Wheel bearing (grease type) service (or every
24 months, whichever occurs first, and whenever
hubs are removed). (23)

Wheels and tires service. (15)

Hydraulic brake service (or every 6 months,
whichever occurs first). (7)
Hydraulic parking brake service (or every 6 months,
whichever occurs first). (8)

Engine drive belts service (or every 12 months,
whichever occurs first). (18)

Clutch pedal free travel service. (10)

Throttle linkage service. (19)

Thermostatically controlled engine cooling
fan service. (4)(20)

Shields and underhood insulation service. (4)(5)(21)

Air intake system service (or every 24 months,
whichever occurs first). (4)(5)(24)

Thermostatically controlled air cleaner service (or
every 24 months, whichever occurs first).
(3)(4)(25)

Evaporative Control System Service (if equipped)
(or every 24 months, whichever occurs first).
(3)(26)

Rear axle air shift motor service. (11)
Check air brake relay valve operation and check for
leaks (or every month, or every 300 hours,
whichever occurs first).
Air brake chamber service (or every 2 months,
whichever occurs first). (41)
Trailer brake hand control valve service (or every
3 months, or 900 hours, whichever occurs first). (42)
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7-17 99,000 Miles (165 000 km)

Engine oil and filter service. (3)(9)

Check fluid levels (or every 3 months, whichever
occurs first). (1)(2)(6)
100,000 Miles (166 000 km)

Change power steering fluid (or every 36 months,
whichever occurs first). (13)

Front axle service (or every 36 months, whichever
occurs first). (38)

Rear axle service
-- Eaton, Rockwell, Spicer Axles
(or every 12 months, whichever occurs first). (1)(37)

Exhaust brake service (if equipped). Check for
excessive spindle free play and smooth operation.
Lubricate ball joint cap.

Accelerator control cable replacement (diesel) (or
every 36 months, whichever occurs first). (19)

Air brake service (or every 12 months, or
3,600 hours, whichever occurs first). (44)
150,000 Miles (240 000 km)

Cooling system service (or every 60 months since
last service, whichever occurs first). (3)(35)
200,000 Miles (320 000 km)

Remove, disassemble, clean and inspect the air brake
trailer supply valve (or every 2 years, or 7,200 hours,
whichever occurs first).
250,000 Miles (400 000 km)

Wheel bearings service -- Eaton Axle (oil-filled) (or
every 36 months, whichever occurs first). (2)(23)

Rear axle service
-- Eaton, Rockwell, Spicer Axles
(or every 36 months, whichever occurs first). (2)(37)

Manual transmission fluid replacement (or every
60 months, whichever occurs first).
300,000 Miles (480 000 km)

Remove, disassemble, clean and inspect the air brake
air dryer (or every 3 years, or 10,800 hours,
whichever occurs first). Replace dessicant on
Bendix
-Westinghouse units.
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7-18 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.
(1) = If your vehicle has an Allison automatic
transmission, your GM Owner's Manual is
supplemented by an Allison Transmission Operator's
Manual. Always refer to these manuals for related
maintenance services.
(2) = Check the fluid level in the manual transmission.
(3) = An Emission Control Service.
(4) = A Noise Emission Control Device.
(5) = Applies only to vehicles sold in the United States.
(6) = Check fluid level in brake master cylinder, clutch
master cylinder (if equipped), power steering pump,
axle, transmission and hydraulic spring parking brake
pump (if equipped). A low fluid level in the brake
master cylinder can indicate worn brake linings and
should be checked accordingly.(7) = 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. Check
brake pedal for excessive free play or travel (or every
6 months, whichever occurs first) and have serviced if
needed. Check brakes more often if driving habits and
conditions result in frequent braking.
(8) = Inspect hydraulic parking brake drum and linings
for wear or cracks and check linkage and adjustment.
Check spring brake actuator and pump for leaks.
Note: The spring brake section of the actuator is
non
-serviceable.
(9) = This vehicle has an Engine Oil Life Monitor. This
monitor will show you when to change the engine oil
and filter
-- usually between 3,000 miles (5 000 km) and
7,500 miles (12 500 km) since your last oil change.
Under severe conditions, the indicator may come on
before 3,000 miles (5 000 km). Never drive your vehicle
more than 7,500 miles (12 500 km) or 12 months
without an oil and filter change.
The system won't detect dust in the oil. So if you drive
in a dusty area, be sure to change your oil and filter
every 3,000 miles (5 000 km) or sooner if the Change
Oil Light comes on. Remember to reset the Oil Life
Monitor whenever the oil is changed. For more
information, see ªChange Oil Lightº in the Index.
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7-19
(10) = Check clutch pedal for free travel. Press pedal
by hand until resistance is felt. Free travel should be
maintained at 1.5 to 2 inches (38 to 51 mm) measured
at the clutch pedal pad. Make checks at 3,000 miles
(5 000 km) and 6,000 miles (10 000 km) and then every
6,000 miles (10 000 km) thereafter.
(11) = Inspect rear axle air shift motor for fluid leaks.
Remove plug to check fluid level. Inspect air lines and
hoses for proper hook
-up, binding, leaks, etc. Inspect at
3,000 miles (5 000 km) and 24,000 miles (40 000 km)
and then every 24,000 miles (40 000 km) thereafter.
(12) = Chassis Lubrication Service: Lubricate all grease
fittings in front suspension, front axle and steering
linkage. DO NOT lubricate kingpin bushings with air
pressure equipment; instead, use a hand grease gun to
ensure complete purge and eliminate sealer cap
distortion. Lubricate transmission and shift linkage,
hood latches and hood hinges, parking brake lever pivot,
clevis pins and linkage, disc brake caliper rails, clutch
linkage and release bearing (if equipped), propeller shaft
slip joint, universal joint, brake camshaft bracket, slack
adjusters, pedal shaft, clutch cross shaft and clutch pedal
springs. Lubricate suspension, axle and steering linkage
more often when operating under dusty or muddy
conditions and in excessive off
-road use.(13) = Check steering system:

Look for damaged, loose or missing parts. Also
look for parts showing signs of wear or lack of
lubrication. Replace parts as needed. Also check
steering gear mounting bolts, pitman arm nut, gear
housing upper cover and side cover attaching bolts,
steering column mounting bolts and cardan
joint clamp bolts; tighten if necessary.
(See service manual.)

Inspect power steering hoses, tubes and fittings for
leaks. Hoses and lines must not be twisted, kinked or
tightly bent. Make sure clips, clamps, supporting
tubes and hoses are in place and properly secured.

Check steering gear for leakage around pitman shaft
and housing. If leakage is evident (lubricant
oozing out, not just oily film), leak should be
corrected immediately.
(14) = Check front and rear suspension. Look for
damaged, loose or missing parts or parts showing signs
of wear or lack of lubrication. Replace parts as needed.
(15) = Adjust tire pressures as indicated on the
Certification/Tire label for optimum tire life. See ªTiresº
in the Index for further details. Check tires for excessive
or abnormal wear or damage. Also check for damaged
wheels. Replace wheels and/or tires as needed.
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7-21
(25) = Check thermostatically controlled air cleaner
installation to make certain that all ducts are connected and
correctly installed. Also, check valve for proper operation.
(26) = Evaporative Control System Service (if equipped):
Check all fuel and vapor lines and hoses for proper
connections and correct routing (or every 24 months,
whichever occurs first). Replace parts as needed.
(27) = Replace air cleaner filter (or every 24 months,
whichever occurs first). Replace filter more often if
driving in dusty conditions. Ask your dealer for the
proper replacement intervals for your driving conditions.
(28) = Replace spark plugs. Inspect wires for damage.
Check the wire boot and boot heat shield fit at spark
plugs and coil. Replace parts as needed.
(30) = Check the fuel tank, fuel cap and fuel lines for
damage which could cause leakage. Inspect fuel cap for
correct sealing ability and any indications of damage.
Check fuel cap gasket for even filler neck imprint.
Replace parts as needed.
(31) = Check EGR system as described in the service
manual. See ªService and Owner Publicationsº in the Index.
(32) = Inspect Electronic Vacuum Regulator Valve
(EVRV) filter for excessive contamination or plugging.
If needed, clean filter with solution of soap and water,
let dry and install.(33) = Check the PCV system for proper operation and
clean PCV valve. Replace hoses as needed.
(34) = Replace PCV valve and blow out the PCV valve
hose with compressed air. Replace hoses as needed.
(35) = Drain, flush and refill cooling system. See
ªRecommended Fluids and Lubricantsº in the Index for
what to use. Inspect hoses. Clean radiator, condenser,
pressure cap and neck. Pressure test cooling system and
pressure cap. For Caterpillar
 diesel engines, always refer
to the Caterpillar Diesel Engine Operation & Maintenance
Manual for coolant recommendations and change intervals.
(37) = Rear axle service: Change the lubricant. See
ªRecommended Fluids and Lubricantsº in the Index.
(38) = Front axle service: Re
-pack upper kingpin
roller bearing.
(39) = Air brake service:

Inspect brake lines and hoses for proper hook
-up,
binding, leaks, cracks, chafing, etc. Inspect drum
brake linings for wear or cracks. Inspect other brake
parts at each wheel, including drums, wheel cylinders
and piston heat shields and boots. Check brake pedal
for excessive free play or travel (or every 6 months,
whichever occurs first) and have serviced if needed.
Check brakes more often if driving habits and
conditions result in frequent braking.
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7-22

Test air lines for leaks; tighten as needed. Replace
compressor filter.

Inspect air parking brake chamber for leaks and
damage. Inspect lines and hoses for leaks, cracks,
chafing, etc. Also check all attachments for
tightness, wear or damage. Note: The spring brake
section of the rear brake diaphragms are
non
-serviceable.

Replace the air compressor filter element, mounted
on the air compressor. For remote air compressor
intake service, refer to air cleaner filter replacement.
(40) = Clean and lubricate air brake automatic slack
adjuster. Check pushrod travel and auto adjustment
operation. Have serviced if needed.
(41) = Air brake chamber service: Check operation,
mounting, clamps and air lines and check for leaks.
(42) = Trailer brake hand control valve service: Check
operation; lubricate cam and follower.
(44) = Air brake service: Remove, disassemble, clean
and inspect the safety valve, standard brake chamber,
quick release valve, quick release/double check valve
combination, parking brake control valve, double check
valve, pressure protection valve and alcohol injector. Remove, disassemble and clean the application valve;
replace parts showing wear. Remove, disassemble, clean
and inspect the spring brake control valve; replace
rubber parts.
(45) = For Stud Piloted Wheels Only: 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. See ªTightening the Wheel Nutsº in
the Index.
(46) = For Hub Piloted Wheels Only: Tighten the wheel
stud nuts to the specified torque values at 1,000 miles
(1 600 km). Thereafter, tighten them 1,000 miles
(1 600 km) after each time the wheel is removed. See
ªTightening the Wheel Nutsº in the Index.
(47) = Short Trip/City Maintenance Schedule. See
ªMaintenance Schedule Definitionº in the introduction
pages at the beginning of this section.
(48) = Long Trip/Highway Maintenance Schedule. See
ªMaintenance Schedule Definitionº in the introduction
pages at the beginning of this section.
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7-24 At Least Twice a Year
Restraint System Check
Make sure the safety belt reminder light (if equipped)
and all your belts, buckles, latch plates, retractors and
anchorages are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from
doing its job, have it repaired. Have any torn or frayed
safety belts replaced.
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace blade
inserts that appear worn or damaged or that streak or
miss areas of the windshield. Also see ªWiper Blades,
Cleaningº in the Index.
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. (See ªRecommended Fluids and Lubricantsº
in the Index.)Body Lubrication Service
Lubricate all surfaces such as door checks, door lock
bolts, lock strike plates, door hinge bushings and
dovetail bumper wedges. Where oil holes are provided,
a dripless oil can be used. The seat adjusters, seat track,
door weatherstrips and rubber hood bumpers should also
be lubricated.
Part C tells you what to use. More frequent lubrication may
be required when exposed to a corrosive environment.
Parking Brake Check
Park on a fairly steep hill and hold the vehicle with the
parking brake only. This checks holding ability.
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7-25
Starter Switch Check
CAUTION:
When you are doing this check, the vehicle could
move suddenly. If it does, you or others could be
injured. Follow the steps below.
1. Before you start, be sure you have enough room
around the vehicle.
2. Firmly apply both the parking brake (see ªParking
Brakeº in the Index if necessary) and the
regular brakes.
NOTE: Do not use the accelerator pedal, and be
ready to turn off the engine immediately if it starts.
3. On automatic transmission vehicles, try to start the
engine in each gear. The starter should work only in
PARK (P), if equipped, or NEUTRAL (N). If the
starter works in any other position, your vehicle
needs service.Automatic Transmission Shift Indicator Check
Check that the indicator points to the gear chosen.
Steering Check
Be alert for any changes in steering action, abnormal
front tire wear or steering wheel position. An inspection
or service is needed when the steering wheel is harder to
turn or has too much free play, or if there are strange
sounds when turning or parking.
Brake System Check
Be alert to illumination of the low air warning lamp or
for the tone alarm, or changes in braking action, such as
repeated pulling to one side, unusual sounds when
braking or increased brake pedal travel. Make sure air
brake system reservoirs are drained daily with full
system air pressure, and check system for leaks. Any of
these conditions could indicate the need for brake
system inspection and/or service.
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