Volvo FH - Auxiliary Brakes

Auxiliary brakes
General
Use auxiliary brakes to avoid overheating in the brakes
on longer downgrades and to reduce wear on the brake
linings.
If the truck is driven on steep downhill slopes without
a load, there is a risk of jack-knifing if the auxiliary
brakes apply too hard.
The brake lamps light if the auxiliary brakes are
applied hard enough.
On vehicles with air suspension which do not have a
full load the braking effect of the auxiliary brake is
diminished.
On tractors without ABS or EBS, the engine brake is
only engaged when a trailer is coupled.
On trucks with
ABS
or
EBS
the auxiliary brakes are
disengaged if the wheels start to lock. The auxiliary
brakes can also be disengaged if the
ABS fails
.
On trucks with
ESP
the auxiliary brakes are also
disconnected if this is necessary to retain stability.
Warning!
Do not use the auxiliary brake on
slippery roads because of the risk
of the wheels locking and of
skidding. The auxiliary brake
brakes only on the drive wheels
which means that there is risk of
jack-knifing. Instead brake with
the brake pedal which acts on all
wheels. Drive with sufficient
safety margins.
Driving instructions for the compact
retarder
Trucks with compact retarders must be run at high
engine speed when the retarder is engaged. If the
engine speed is too low, the oil will not be cooled
properly. If the oil is not cooled properly, the effect of
the compact retarder will be reduced and remain low
until the oil temperature is sufficiently low again. High
engine speed when braking does not negatively effect
fuel consumption.
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Driving