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port and the No . 2 port to be blocked .
Air
flows instead from the bellows through open
solenoids "E" and "F", and then from the No . 2
to the No. 1 (exhaust) ports in solenoids "C"
AIR BELLOWS
The air bellows for the tandem rear wheels
are mounted between the control arms .
On
each side of the air bellows is a piston which is
connected directly to the control arm.
The air bellows serve as a flexible con-
nection between the two control arms on each
side of suspension bracket. The flexing of the
air bellows allows the control arms to move up
and down in relation to the frame. This action
absorbs road shocks in the same manner as an
inflated rubber tire cushions shock caused by
roa ' roughness.
SHOCK ABSORBERS
A double acting shock absorber is used at
each wheel on the rear suspension . The shocks
are mounted to the top of the control arms and
to the frame at the bottom .
The shock absorbers are gas filled cell-type
shocks .
They are filled with a calibrated
amount of fluid and sealed during production .
They are non-adjustable, non-refillable and
cannot be disassembled . The only service they
require is replacement if they have lost their
resistance, are damaged or leaking fluid .
HEIGHT CONTROL VALVE
(Refer to Figure 8)
Height control valve automatically main-
tains a constant vehicle height by controlling
the flow of compressed air into or out of
suspension system air bellows. A delay piston
in each valve provides a momentary delay in
intake and exhaust valve action .
Therefore,
air in bellows is exhausted only during load
changes and not during intermittent road
bumps.
The height control valve contains an intake
valve, air bellows outlet, exhaust valve, delay
piston, and overtravel control body.
The
overtravel control body contains a spring-
loaded nylon piston which protects valve parts
if overtravel lever is moved beyond normal
operating range .
SYSTEM COMPONENTS
Air Inlet Port
Air Exhaust Port
REAR SUSPENSION 4-7
and "D" .
Thus the vehicle ride height lowers
by the release of air to the atmosphere
through the exhaust ports of the "LOWER"
solenoids .
HEIGHT
CONTROL
VALVE
OPERATION-
(FIGURE - 9)
Loading
When vehicle is being loaded, frame tends to
settle.
Since valve is linked to control arm,
and valve is bolted to wheel well, valve moves
downward with frame as vehicle is loaded . As
valve arm and control shaft turns, a force is
applied to the delay piston which moves slowly
and allows the intake valve lever to move
against the intake valve core . As
pin
is pushed
in, air pressure flows through height control
valve into bellows.
Increased air pressure
expands the bellows and raises frame.
Inlet valve is "PROTECTED" by check valve
in inlet adapter.
Light spring in core freely
admits reservoir air, but return flow of air is
blocked.
Neutral Position
As increased air pressure expands bellows
and lifts frame, the height control valve moves
upward with frame. As frame is returning to
normal ride height, valve arm and shaft return
to a neutral position .
Inlet valve lever also
moves away from inlet valve core and inlet
valve closes .
This stops the flow of the air
into bellows.
The exhaust valve remains
closed . Since the exhaust valve is closed, and
the check valve in the inlet adapter prevents
compressed air from returning to air reservoir,
air is trapped in bellows and in valve .
No
Bellows Port
Figure 8-Height Control Valve (Port Identification)
T .16]6
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