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MAINTENANCE
Crusader
MC-8
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DATE--=-=Ju' - -' - +ly-L-,
_19-----' - -73 _ _ ] ·
MANUAL
SUSPENSION
SUSPENSION
DESCRIPTION
The coach is provided with an air suspension
system. The system consists of air beams, air bellows,
height control valves, radius rods, and shock ab-
sorbers. The 5'1/Stem is entirely automatic in operation
and is designed to maintain a constant vehicle height
regardless of loading. Rear trailing wheels use
rolling-lobe type bellows. Air pressure in these
bellows is controlled by a pressure regulating valve
which maintains constant pressure in bellows and
uniform loading of the rear trailing wheels regardless
of total vehicle loading. Refer to Section 4 "Brakes &
Air System" for regulating valve pressure setting.
Air beams are used to provide a larger volume of
air for better ride characteristics. Two such beams
are located above the fruni a11J rear axle as part of
the coach body structure.
Suspension bellows assemblies are made from a
special compound rubber and nylon tire fabric, and
moulded to the proper contour and dimensions. The
entire vertical load of the coach is taken by these
bellows. Bellows are attached to both the axle sup-
ports and air beams by bead rings and special bolts,
forming an air-tight seal.
Radius rods are used to hold the axles in the
proper transverse and longitudinal position. Four
radius rods are used at the rear axle and five at the
front axle. These rods transmit both braking and
driving forces from the axles to the coach body.
Delay-type
height
control
valves
increase or
decrease the air pressure in the air beams as required.
Two height control valves are located at the rear
axle, and one at the front axle. The valves are moun-
ted on the coach body and are connected to the axles
by
rubber-bushed
links.
Because
of the
delay
mechanism in each height control valve, the valves
respond only to sustained variations in the height of
the axles in relationship to the coach body. Thus no
change in air pressure takes place during normal
driving. However, the valves automatically regulate
air pressure in the air beams to compensate for
changes in the load carried by the coach, or due
to
changes in the location of the coach load.
Double-acting shock absorbers are used to improve
ride characteristics. Two shock absorbers are used at
the front axle, four at the rear and two at the rear
trailing wheels.
An auxiliary air system is provided to supply com-
pressed air for the operation of the system. Com-
pressed air from the main system is fed to an auxiliary
tank.
MAINTENANCE
The
suspension
system
requires
no
periodic
lubrication except at the rear trailing axle trunnions.
These should
be greased
using a
molybdenum
disulfide grease. Refer to "Lubrication" (Section 10)
of this manual. Routine maintenance should also in-
clude usual inspection procedures, and occasional
tests to determine that correct coach body height is
being maintained.
FRONT AXLE
REMOVAL AND REPLACEMENT
To remove the entire front axle assembly, first
block the rear wheels to prevent the vehicle from
rolling. Raise the front end of the coach until the bot-
tom of the coach body is approximately 18" from the
floor. Block the body in this position as indicated in
Section 3 (Body) under "Coach Jacking Points."
CAUTION:
Do not raise the body in such a way
that the entire weight of the front axle will hang on
the suspension bellows assemblies. Otherwise damage
to the bellows may result.
Exhaust air pressure from the suspension air tank
by opening the drain cock at the bottom of air filter.
Disconnect the height control valve link, and pull
down on height control valve arm to exhaust air from
the front inner beams. Disconnect the hose from the
front brake chambers. Disconnect the steering drag
link.
Disconnect both ends of all radius rods as outlined
later in this section under "Radius Rods".
Remove nuts from all bolts attaching air bellows
lower bead rings to suspension supports. Remove
shock absorbers as outlined later in this section un-
der "Shock Absorbers".
Lower the axle assembly on jacks until bellows
bead ring bolts are cleared of the suspension sup-
ports. The axle can now be carefully removed from
under the vehicle.
Reinstallation of the axle assembly is the reverse of
removal. Make sure that bellows mounting pads on
suspension supports are clean.
REAR AXLE
REMOVAL AND REPLACEMENT
Block front wheels of the coach to prevent ro!ling.
Raise the rear end of the vehicle with jacks until the
bottom of the body is approximately 18" fr?m t~e
floor. Block the body in this position ~s outl_me~, m
Section 3 (Body) Under "Coach Jackmg Pomts .
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