Chevrolet Low Cab Forward 2016 Manual page 268

Checking the Brake Electric
Vacuum Pump (3500HD/4500
Series)
1. Turn the engine control switch
to the "ON" position (do not
start the engine), and press the
brake pedal several times.
2. Check for the noisy sound of
the electric vacuum pump
inside the instrument panel at
the same time as vacuum
warning buzzer sound, and
check that the brake low
vacuum warning light
comes on.
3. Then, start the engine. The
main vacuum pump driven by
the engine will start running.
If the electric vacuum pump
operation (noisy sound) and
the vacuum warning buzzer
stop, and the brake low
vacuum warning light goes off
thereafter, the operation is
normal.
4. If you cannot hear the noisy
sound or the noisy sound stays
on all the time, have the
vehicle inspected by the
nearest dealer immediately.
Brake Pedal
Stroke
Shut off the engine and press the
brake pedal about 10 times strongly,
then check the brake pedal for free
play by lightly pushing it by hand
until you feel resistance.
Vehicle Care
Free play (measured at the tip of
pedal)
4 - 7 mm (0.16 - 0.28 in) (Gasoline
Vehicles)
5 - 10 mm (0.20 - 0.39 in) (Diesel
Vehicles)
1. Clearance from the floor.
2. Brake pedal bracket.
Next, start the engine, and wait at
least 1 minute. Then press the
brake pedal and measure the
clearance (1) of the pedal from the
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