OPERATOR'S MANUAL

Preventive Maintenance Air System
Medium Duty
(R05/09) Y53-6027 – 195 –
AIR SYSTEM
Introduction
WARNING! Prior to the removal of any air system
component, always block and hold the vehicle
by a secure means other than the vehicle's own
brakes. Depleting air system pressure may
cause the vehicle to roll unexpectedly resulting
in an accident causing death or injuries. Keep
hands away from chamber push rods and slack
adjusters, they may apply as system pressure
drops.
• Never connect or disconnect a hose or line
containing air pressure. It may whip as air
escapes. Never remove a component or pipe
plug unless you are certain all system pres-
sure has been depleted.
• Never exceed recommended air pressure
and always wear safety glasses when work-
ing with air pressure. Never look into air jets
or direct them at anyone.
• Never attempt to disassemble a component
until you have read and understood recom-
mended procedures. Some components
contain powerful springs and injury or death
can result if not properly disassembled. Use
only proper tools and observe all precau-
tions pertaining to the use of those tools.
• Completely bypassing a Bendix AD-IS air
dryer will bypass the system’s pressure pro-
tection valves. This could lead to loss of air
pressure or damage to the vehicle’s air sys-
tem, which could cause an accident involv-
ing death or personal injury. Always adhere
to the manufacturer’s procedure if it is nec-
essary in an emergency to temporarily
bypass an AD-IS-series air dryer.
WARNING! Do not release the parking brake or
attempt to move the vehicle until air pressure in
both circuits is at least 100 psi (690 kPa), the
level required for normal brake operation.
• Do not use the trailer hand brake control to
hold vehicle while parked. This control uti-
lizes air pressure for brake application.
Because acceptable air leakage levels cause
all truck air systems to gradually lose pres-
sure, vehicle rollaway could occur, resulting
in an accident and death or injuries.
• Always apply the tractor and trailer parking
brakes when the vehicle is unattended.