3-9
SECTION 3 –
DRIVING YOUR MOTOR HOME
ENGINE BRAKE SYSTEM
Freightliner
®
Chassis
Many large diesel trucks are equipped with a
compression release engine brake system,
commonly referred to as a “jake brake”– so
named for Jacobs Vehicle Systems
™
, the
originator of this type of braking system.
The engine brake is a device mounted on top
of the diesel engine that temporarily changes the
timing of the exhaust valves, momentarily
shutting down either three cylinders or all six
cylinders, depending on Low or High setting.
This turns the power-producing diesel engine
into a power-absorbing compressor, which
provides effective deceleration of the vehicle.
Combined with use of the chassis air brakes, the
engine brake delivers a substantial degree of
braking power.
The engine brake activation switch is located
on the lower left side of the dash. Press and
release the ON side of the switch to activate the
engine brake system. The engine brake will
operate whenever you let up on the throttle pedal
while the switch is ON.
Further Information
See your chassis manual in your InfoCase for
more instructions, information, and precautions
on using this feature.
HAZARD WARNING FLASHERS
The hazard warning flashers provide
additional safety when the vehicle must be
stopped on the side of the roadway and presents a
WARNING
Do not activate the engine brake system
while on icy or extremely wet roads or in
any other situation where abrupt
deceleration could cause skidding or loss
of vehicle control.
Engine Brake Operation
•
Low – Press for normal braking
on level or
shallow grades and in-town and city driving.
This shuts down three of the six cylinders when
engaged and provides about 130-hp of braking
power. The switch indicator light will be on.
•
High – Press for additional braking on steep
grades
and mountain driving. This shuts down
all six cylinders when engaged and provides
about 300-hp of braking power. The switch
indicator light will be on.
•
The middle position is Off.
The engine brake
is deactivated. Only the chassis air brakes are
active at this setting. The switch indicator light
will be off.
