Holiday imperial 2001, Owner'S Manual, Page: 246 / 301

Chassis Information
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I M P E R I A L
1 0 • 2 4 6
bags is coupled with a Bilstein gas shock absorber. The suspension control
arms are attached to the frame through bushings, which require no lubrication.
The suspension ride height is preset and will maintain the proper ride height
automatically, regardless of the load.
The air compressing system on the motorhome is comprised of several
items: an air compressor, air governor, air dryer, a front air tank and a rear air
tank. The compressed air system operates several items, some of which include
brakes, suspension, air horns, air gauge and stepwell cover. The air system is
charged by a gear driven air compressor mounted on the engine. As engine
speed increases, compressed air output increases. When the air is compressed,
heat is generated. Heat dissipates as the air is discharged from the compressor.
Moisture condenses in the compressed air as it cools. The moisture laden air
then enters an air dryer where the air is filtered. The filtered air charges the
front air tank. The front air tank is divided in two halves: a wet side and a dry
side. The compressed air enters the wet side before entering the dry side. A
discharge line from the dry side of the front air tank charges the rear air tank.
The discharge lines use inline check valves to prevent back flow of compressed
air.
The pneumatically operated items are divided into two categories: brakes
and accessory air. Brakes have full use of supplied air pressure. Accessory air
items such as air horns or stepwell covers receive air through pressure protec-
tion valves (PPV). The PPV will not allow compressed air flow until approxi-
mately 60 psi. In the event of an air system problem the pressure protection
valve will leave a reserve air charge for braking. Pressure protection valves are
installed for safety.
The air governor is located in the engine compartment. The air
governor performs two functions: regulating the air compressor to
cut-in and cut-out keeping the air system in the specified operating
range of 105-120 psi; sending an air “purge” signal to the Air Dryer.
Cut-in pressure of approximately 105 psi is factory preset from the
governor manufacturer and is not adjustable. Cut-out pressure is cali-
brated to 120 psi. When cut-out pressure is reached the governor will
send an air purge signal to the Air Dryer. This opens the purge port of
the Air Dryer, expelling moisture. The purge action of the Air Dryer
is identified by the short release of air at the rear of the motorhome.
AIR GOVERNOR
AIR SUPPLY
SYSTEM