Exhaust Brake Maintenance; Brake - Auxilary; Brake - Exhaust - Monaco 2002 Diplomat Service Manual

Chassis Information
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BRAKE -
AUXILIARY

BRAKE - EXHAUST

Exhaust Brake
Maintenance
1 0 • 2 9 0
Auxiliary braking devices are designed to supplement a standard wheel
braking system. These devices are not designed to bring the motorhome to a
complete stop; however, they can assist in controlling the speed of the
motorhome. Proper use of the auxiliary braking device can save on costly
service brake repairs.
The exhaust retarder is an auxiliary braking device which is attached
directly to the engine turbocharger. The exhaust brake is operated by either a
dash switch or a foot operated switch. The dash mounted switch will operate
the exhaust brake when dash switch is ON and the throttle is RELEASED.
If the motorhome has a foot operated exhaust brake switch it will not
disengage the cruise control. Application of the service brake is required to
disengage the cruise control. When the exhaust brake is activated a flapper
inside the exhaust brake moves and restricts the flow of exhaust gases and caus-
es an increase of exhaust pressure within the engine.
The increased back pressure quickly slows the engine speed, resulting in
powerful engine braking action. When the exhaust brake is activated, the
amount of engine braking power developed is related to engine speed
(RPM). When a exhaust brake application is made, the engine braking effect
increases with higher engine RPM. When the exhaust brake is activated
going down a hill, the exhaust brake will help control road speed or slow
down the motorhome's road speed until the Allison Transmission automatically
downshifts to the next lower gear. Downshifting automatically occurs from
high gear down through second gear. Certain road conditions and engine
speeds may require the transmission be manually down shifted in order to
generate adequate engine RPM and increase the engine brake effect.
The Exhaust Brake system, used routinely at normal exhaust operating
temperatures, is virtually maintenance free. Some contributing causes which
can result in failures with the exhaust brake include moisture, dirt, carbon
and improper usage.
Starting the engine and idling for short periods of time is not recommended.
Moisture is created within the engine and the exhaust system during cold
startups. When normal operating temperatures are not obtained, moisture
may get trapped in the valve housing resulting in rust, leading to insufficient
operation of the exhaust brake.
Some problems you may encounter with the exhaust brake include, but
are not limited to, will not activate or deactivate, intermittent on/off operations
or actuates with the switch off. These are commonly related to electrical
symptoms. Slow operations or delays in operations, as well as limited
performance, are mechanical symptoms. Refer these problems to your dealer
for diagnosis.
D I P L O M A T