Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
Instruments and Controls 85
The brake system warning light
comes on while the engine is
running (after startup) in the
following situations:
.Drop in the level of brake fluid
(due to brake lining wear or fluid
leakage).
. Abnormality in the charging
system (such as an alternator
malfunction or loose or split
fan belt).
. Abnormality in the anti-lock
brake system (ABS) and EBD
functions. (The ABS warning
light and brake system warning
light will illuminate at the same
time.) See Antilock Brake
System (ABS) Warning Light
0 87.
To serve as a reminder, the light
should stay on when the parking
brake is not fully released, and the
engine control switch is on. Have
the system repaired if the light does
not come on when it should. If this
warning light does not go away,
brake inspection and maintenance
should be performed.Check and Corrective Action
1. Check to see that the parking brake has been fully released.
If it has, check the following:
2. For diesel vehicles, turn on the exhaust brake to help slow the
vehicle.
3. Pull off the road and stop carefully. Remember that
stopping distances may be
longer, the pedal may be
harder to push and go down
farther than normal.
4. Check the brake fluid reservoir on the left side of the
instrument panel. If low, add
fluid as needed.
5. If the brake fluid is not low: Try out the brakes by starting and
stopping on the shoulder of the
road, then either drive
cautiously at a safe speed to
the nearest dealer for repair,
if you judge driving to be safe;
or have the vehicle towed to
the nearest dealer for repair. Continued driving without the
necessary repairs could be
dangerous.
If this warning light stays on, see
your dealer.
The regular braking system is a split
system designed so that one part
will provide some braking if there is
a loss of hydraulic pressure in the
other part of the system.
{Warning
If this warning light comes on
while the engine is running,
immediately stop the vehicle at a
safe place well clear of traffic and
contact your dealer for inspection.
When the brake system warning
light is illuminated, brake
effectiveness may be decreased.
When this happens, strongly
press the brake pedal.
See Brakes 0275.
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
86 Instruments and Controls
Parking Brake Light
This indicator light comes on when
the parking brake lever is pulled
with the engine control switch on.
This light also stays on when the
parking brake is not fully released
and the engine control switch is on.
If this warning light stays on, see
your dealer.
The illumination of the parking brake
light does not necessarily ensure
firm application of the parking brake.
The parking brake lever must be
sufficiently pulled up and locked.
Be careful not to drive the vehicle
with the parking brake lever still
pulled up.
Brake Low Vacuum Warning
Light
This light should come on briefly
when the engine control switch is
turned to the ON position, and then
should go out after the engine is
started. If the light does not come
on when the engine control switch is
turned to ON, it could indicate a
burned out bulb or a blown fuse.
Have the system repaired if the light
does not come on during this check.
The warning light and buzzer will
come on simultaneously when the
brake booster’s vacuum or pressure
becomes insufficient either during
driving or when the engine control
switch is in the ON position, or when
there is an abnormality in the
charging system, such as an
alternator malfunction or loosening
or splitting of the fan belt or
whenever the hydraulic brake booster (HBB) becomes faulty. The
warning buzzer will stop sounding
when the parking brake is engaged.
On 4500, 4500HD, and 4500XD, the
brake low vacuum warning light and
warning buzzer should come on to
indicate low vacuum reserve for
brake power assist. At the same
time, the Back up Electric Vacuum
Pump operates.
(5500HD, 5500XD models) When
the HBB pressure is low, and/or the
HBB fluid (Dextron©
–III) level is
low, the light and warning buzzer
should come on. Do not use brake
fluid in the brake booster reservoir.
Use only Dextron© –III ATF.
4500 models are equipped with a
Back up Electric Vacuum Pump that
will turn on if brake booster vacuum
becomes insufficient.
If this happens while driving:
. Do not pump the brakes. The
system is designed to stop the
truck with reserve power assist if
the pedal is held down. This
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
364 Service and Maintenance
conforms to this maintenance
schedule. (Recommended oil: CK-4
(API designations))
4. Fuel Filter :Replace the fuel
filter every 24 000 km (15,000 miles)
or more frequently if clogged or
replace when the fuel filter indicator
light comes on (if equipped).
5. Pre-Fuel Filter/Water
separator : Replace the fuel filter
every 24 000 km (15,000 miles) or
more frequently if clogged or
replace when the fuel filter indicator
light comes on (if equipped).
6. Air Cleaner Filter : The level of
dirt in the air cleaner element can
be checked against the indicator.
Replace the air cleaner filter when
the multi-information display (MID)
shows "CHECK AIR FILTER".
7. Damage to Air Intake Ducts and
Hoses : Check for damage of air
intake ducts and hoses and that
those are correctly installed every
24 000 km (15,000 miles) or
12 months. Replace or adjust those
if necessary. 8. Drive Belts :
Check belt driving
the fan, alternator or A/C
compressor every 16 000 km
(10,000 miles). Look for cracks,
fraying, wear, and proper tension.
9. Engine Bolt Torques : Loosened
bolts result in lower engine output.
Check and adjust manifold
mounting, and injectors to correct
torque every 80 000 km
(50,000 miles).
10. Rotate Tires : To equalize wear,
rotate tires and adjust tire pressures
every 10 400 km (6,500 miles). See
Tire Rotation 0323.
11. Engine Cooling System : At
12 months or 16 000 km
(10,000 miles) intervals, wash
radiator cap and filler neck with
clean water, pressure test system
and radiator cap for proper pressure
holding capacity, tighten hose
clamps and inspect condition of all
cooling and heater hoses. Replace
hoses if cracked, swollen or
otherwise deteriorated. Have the
hoses replaced by your authorized
dealer. 12. Engine Coolant :
Inspect the
engine coolant every 12 months.
Replace the engine coolant every
24 months, drain the engine coolant
by opening the drain plug at the
bottom of the radiator core, flush
and refill the engine cooling system
with a new engine coolant. Refer to
"Preparing Engine Coolant" in
Engine Coolant 0263. Have the
Engine Coolant replaced by your
authorized dealer.
13. Exhaust System : Check the
complete exhaust system every
16 000 km (10,000 miles). Check
body areas near the exhaust
system. Look for broken, damaged,
missing, or out-of-position parts.
Also inspect for open seams, holes,
loose connections, or other
conditions which could cause heat
build-up at the rear body floor pan,
or could let exhaust fumes seep into
the passenger compartment. Dust
or water in the cabin may indicate a
leak in that area. Required repairs
should be made at once.
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
394 Technical Data
Rotor thickness[Standard Value] 40.0 mm (1.575 in) 42.0 mm (1.654 in)
[Usable Limit] 37.0 mm (1.457 in) 39.0 mm (1.535 in)
Pad thickness [Standard Value] 13.0 mm (0.512 in) 13.0 mm (0.512 in)
[Usable Limit] 1.0 mm (0.04 in) 1.0 mm (0.04 in)
Service Brakes
Brake pedal free play Refer to Brakes0275.
Clearance between the brake pedal and the brake pedal
bracket (applied to the brake pedal)
Parking Brake
Lever effective stroke (Under pull force of approx. 147 N (15 kg/33 lb) 6 - 8 notches
Electrical System
Model 3.0 Diesel Engine 6.0L Gasoline Engine 5.2 Diesel Engine
Battery type [BCI size] (RC-CCA) x No. of units 31T (160 - 750) x 2 31 (180 - 750) x 1 31 (160 - 750) x 2
*7
Starter
12 V - 2.0 kw12 V - 1.7 kw12 V - 3.0 kw
Alternator 12 V - 140 amp12 V - 145 amp12 V - 140 amp
Tightening Torque
Model 3.0 Diesel Engine 6.0L Gasoline Engine 5.2 Diesel Engine
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
396 Technical Data
Engine Drive Belt Routing
Fan Belt and Air Conditioning
Compressor Belt
See theMaintenance Schedule
0 345.
3.0L L4 Engine (IZ3)
No. Name
1 Fan Pulley
2 Tension pulley
3 A/C compressor
4 A/C belt
5 Crank pulley
6 Idler No.
Name
7 Alternator
8 Fan belt
If your air conditioning system is
functioning properly, it is not
necessary to remove and replace
the refrigerant or compressor oil.
6.0L V8 Engine (L96)
No. Name
1 Fan belt idler pulley
2 Alternator
3 Vacuum pulley
4 Power steering pump pulley No.
Name
5 Cooling fan pulley
6 Crank pulley
7 A/C belt
8 A/C compressor
9 Fan belt
10 Fan belt tensioner
5.2L L4 Engine (I1B)
No. Name
1 Fan belt
2 Fan pulley
3 A/C belt
Chevrolet Low Cab Forward Owner Manual (GMNA-Localizing-U.S.-
10716700) - 2017 - crc - 12/6/16
Technical Data 397
No.Name
4 A/C compressor
5 Tension pulley
6 Crank pulley
7 Alternator
If your air conditioning system is
functioning properly, it is not
necessary to remove and replace
the refrigerant or compressor oil.
. A V-ribbed belt is used for the
fan belt. This type of belt
requires the tension to be
adjusted more accurately than is
required with the conventional V
belt. Inappropriate tension could
cause the belt to make noise or
break. When the fan belt is
damaged, electricity is not
properly generated or becomes
a cause of engine overheating.
You must check the tension of
the fan belt carefully.
. Use dealer-certified genuine
parts when changing the
fan belt. .
Have the vehicle inspected and
serviced at your dealer.
. The air conditioning drive belt,
if equipped, must be adjusted
after fan belt adjustment. If the
belt is not adjusted properly, the
A/C belt may experience
excessive tension, and possible
premature failure.