Chevrolet Low Cab Forward 6.7L 2022 Owner's Manual page 212

the drain tap at the bottom of each air
tank. Allow the air in each tank to be
dischared.
Brake Air Pressure Warning Light
3. Start and run the engine at idle. The
brake air systems are in order if the
brake air pressure increases to the
typical air brake pressure shown above,
the Air Dryer discharge valve opens and
the brake air pressure warning light
goes out.
The amount of time before the brake air
pressure warning light goes out may vary
depending on the temperature and other
environmental conditions. However, you
should contact the nearest dealer if air
pressure does not increase at all or the
brake air pressure gauges show different
pressures after the Air Dryer discharge valve
opens.
Warning
Do not operate the vehicle while any of
the pressure gauge needles are in the red
zone or the brake air pressure warning
light is on. Brakes are then not fully
functional, and it is dangerous to operate
the vehicle.
Brake Pedal
Free Play
Press the brake pedal with two fingers to
check that the pedal free play is proper and
the pedal moves smoothly without
abnormal interference.
Vehicle Care
Free play (measured at the tip of pedal)
10 - 18 mm (0.39 - 0.71 in)
Brake Valve Operation
Release the brake pedal after stepping on it
to check that an air release sound comes
from the exhaust hole at the brake valve
and the pedal fully returns to the released
position.
Brake Performance
Drive the vehicle slowly on a dry road and
apply the brakes. Check that the brakes are
working fully and does not pull on one side.
A brake performance check should be
performed on a wide road with good
visibility while paying adequate attention to
the traffic behind your vehicle and the
overall surroundings.
A small amount of brake squeak is normal.
Drum brakes do not have a brake lining
wear indicator to cause a squeak or squeal.
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