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XL-AS20067BM-en-US · 2021-02-05 · Amendments and Errors Reserved · © SAF-HOLLAND, Inc., SAF-HOLLAND, HOLLAND, SAF,
and logos are trademarks of SAF-HOLLAND S.A., SAF-HOLLAND GmbH, and SAF-HOLLAND, Inc.
Standard Air Control System with PosiLift AN / AS
5. Manual Lift Air Control System
The manual lift valve air control system
(Figure 7)
depicts
a standard tandem axle fixed frame suspension
plumbing diagram.
The air control system uses air drawn from the tractor
air system to pressurize the suspension’s air springs. The
suspension, working with the air control system, provides
optimum suspension performance only when all air control
system components are installed and operating properly.
IMPORTANT:
Make certain that all air lines and valves
are free from obstruction through the full
operational range of the suspension.
The height control valve regulates the air pressure required for
varying capacities of load. It is critical to make sure the height
control valve is set at the proper suspension ride height.
Failure to match the linkage length to
the design ride height could result in
improper suspension height which,
if not avoided, could result in damage
to trailer components.
The manual air release valve isolates the height control valve
out of the air control system, exhausts lift axle suspension air
springs and inflates the PosiLift air springs when activated.
Figure 7
SUSPENSION
AIR SPRING
HEIGHT
CONTROL
VALVE
MANUAL AIR
RELEASE VALVE
FROM SUPPLY
EXHAUST
CONTROL ARM
(NEUTRAL POSITION)
PRESSURE
PROTECTION
VALVE
AIR RESERVOIR
POSILIFT AIR
SPRING
POSILIFT
AIR SPRING
END OF PPV THAT READS
“
IN
”
CONNECTS TO AIR RESERVOIR
SUSPENSION
AIR SPRING
SUSPENSION
AIR SPRING
TO POSILIFT
AIR SPRINGS
TO SUSPENSION
AIR SPRINGS
FROM HCV
