Volvo VNL Operator's Manual page 287

282 Brakes
WARNING
Do not set the vehicle in motion if the
parking brake is engaged. An alarm will
sound if you do. Movement of the truck
while the parking brake is set can cause
brakes to overheat. This may lead to
wheel end fire. To avoid overheating,
make sure both parking brake knobs are
pushed in before driving off.
There are several ways to determine if the
parking brakes have been set. By pulling
out the yellow knob:
•
An audible rush of air will be heard
when the parking brake knob is pulled.
The air exhausts from the park brake
valve itself and from the spring brake
chambers on the rear axle(s).
•
A black ring around the base of the
yellow control knob will be seen.
•
There will be a fluctuation in the air
pressure gauge needles.
•
You will not be able to pull the knob
out any further.
Do not attempt in any way to disassem-
ble or tamper with the spring brake
chamber. The force stored in the spring,
if suddenly released, can cause personal
injury or death.
Do not apply the parking brake while
the vehicle is moving. The rear wheels
may lock up causing loss of vehicle con-
trol leading to an accident with personal
injury or death.