ACCESSORIES 15-12
VACUUM
(WIT
P
VACUUM Llh
, AIR SUPPt
LINES
t
SUPERLIFT F
SHOCK ABSO
OPERATED AIR COMPRESSOR
H STORAGE TANK AND
RESSURE REGULATORJV
\A
4E FROM ENG«NE^"^
/ \-HEIGHT CONTROL
•^-Z n VALVE (WITH TIME
^*
DELAY MECHANISM)
EAR II
RBERS
Fig.
12 - Automatic Level Control Schematic
sure,
alternatley to opposite sides of the compressor
diaphragm.
As the compressor cycles, the reservoir air pressure
gradually increases causing a back pressure on the sec-
ond stage piston until it equals the push of pressure
against the diaphragm- At this point, a balanced condi-
tion is reached and the unit stops operating. After res-
ervoir pressure drops due to system air usage, the com-
pressor again begins to cycle and replenish the
reservoir.
Pressure balance will depend upon the prevailing mani-
fold vacuum and atmospheric pressure. Both are af-
fected by altitude above or below sea level. Balance
pressure will vary from approximately 150 to 275 psi.
NOTE: After completion of work on this sys-
tem or when servicing other parts of the car and
the system is deflated, inflate the reservoir to
140 psi or maximum pressure available through
the compressor service valve.
The PRESSURE REGULATOR VALVE is preset and
limits the reservoir outlet pressure to approximately 125
psi to avoid damage to the height control valve and Super-
lift shocks.
The HEIGHT CONTROL VALVE, which is mounted on
the frame, senses rear car height through a link attached
to the right rear upper control arm. When load is added
to the car, the overtravel lever is forced up causing an
internal lever to open the intake valve, when this valve
is open high pressure air is admitted to the Superlift
shocks. As the car raises to level, the intake valve shuts
off.
When load is removed from the car, the overtravel
lever is forced down causing the internal arm to open the
exhaust valve. As the car lowers to the level position,
the exhaust valve shuts off.
A four to eighteen second time delay mechanism, which
is built into the height control valve, prevents air trans-
fer due to normal ride movements. The overtravel
lever, which pivots around the control valve shaft, rides
off the flat side of the control valve shaft and does not
have time to. react to the rapid changes or normal ride
motions.
During changes due to loading, the time delay mecha-
nism will allow the overtravel shaft to open either the in-
take or exhaust' valve as required, since this is not a
rapid movement.
The SUPERLIFT shock absorber is essentially a con-
ventional hydraulic unit with a. pliable nylon reinforced
neoprene boot acting as an air chamber.
The unit will extend when inflated and retract when de-
flated by the control valve.
An eight to fifteen psi air pressure is maintained in the
Superlift at all times to minimize boot friction- This is
accomplished by a check valve in the exhaust fitting on
the control valve. Neither shock absorber function nor
conventional ride motions thru rear coil springs is im-
paired in the event of accidental air pressure loss. .
A combination of steel tubing and reinforced rubber
hose is used for air lines throughout the system.
-SUPERLIFT
PORT
STATION WAGON
& SEDAN
INTAKE
PORT
HAUST
PORT
Fig. 13 - Height Control Valve
AIR CHAMBER
BOOT
AIR DOME AIR PISTON
Fig. 14- Superlift Absorber
CHEVROLET CHASSIS SERVICE MANUAL
