System - Winnebago 2004 Ultimate Freedom Owner's Manual

SECTION 2
DRIVING YOUR MOTOR HOME
Parking Brake Knob
Use the parking brakes whenever the vehicle
is parked. Never try to drive the vehicle with the
park brake applied. This can cause excessive
wear on the brakes and may damage the transmis-
sion.
NOTE: It is normal to hear an occasional burst
of air pressure from the rear of the vehi-
cle. This is an automatic moisture purg-
ing feature of the air brake system. See
the Brakes section of your Spartan chas-
sis manual for instructions on periodic
draining of brake air tank.
®
JACOBS ENGINE BRAKING

SYSTEM

(Jake Brake)
Many large diesel trucks are equipped with
compression release engine braking systems also
known as "Jake Brakes".
They are called Jake Brakes because the orig-
inal maker of this type of braking system was Ja-
cobs Vehicle Systems, the brand which is
equipped on the engine of your coach.
The Jacobs Engine Brake is a hydraulically
operated device mounted on the top of the diesel
engine that changes the timing of the exhaust
valves and increases engine vacuum.
The idea behind a Jake Brake is to use engine
vacuum to provide braking power. If you've ever
driven a stick shift car and downshifted to pro-
2-4
vide braking, you were using engine vacuum to
slow the car down.
The exhaust retarding action of the Jake Brake
takes this a step further. It actually turns the pow-
er-producing engine into a giant, power absorb-
ing air compressor, which provides effective
braking power, especially on long downgrades.
Engine Brake Switch
To Use the Engine Brake: 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.
Press and release the OFF side of the switch to
deactivate the engine brake system and return to
chassis air brakes alone.
WARNING
Do not activate the engine exhaust
braking system while on icy or
extremely wet roads or in any other
situation where abrupt deceleration
could cause skidding or loss of vehi-
cle control.