User Manual

into the chambers where it is used to apply
your truck and trailer brakes. That is why
,
when you push down on your brake pedal,
you don’t feel the same amount of
pressure on the pedal that you do when
you apply the brakes on your car. All you
are doing on your truck is opening an air
valve to allow air to flow into the brake
chambers. Contamination of the air supply
system is the major cause of problems in
air-operated components such as brake
valves, and suspension height control
valves. To keep contaminants to the lowest
possible level, follow these maintenance
procedures.
Daily Checks
• Drain moisture from the supply and
service air tanks.
• Operate air devices to circulate
lubricant within the unit.
Periodically
• Clean filter screens ahead of the
valves by removing the screens
and soaking them in solvent. Blow
them dry with pressurized air
before reinstalling them.
Twice a Year
•
Maintain the air compressor to
prevent excessive oil bypass. See
your maintenance manual for
details.
• Replace worn seals in valves and
air motors as needed.
Dual Air System Function
Test
Conduct this test at least every 3 months
or if there is any indication of a potential
problem.
Park the vehicle on level ground and block
the wheels. Have an assistant open drain
valves and, where required, observe brake
action at the wheels. If a malfunction
occurs during this test, do not move the
vehicle until the problem has been
corrected. Engine should be Off with the
key switch to the ON or RUN position.
NOTE
Tractor air system must be connected
to trailer
.
Air Dryer Maintenance
NOTE
Because no two vehicles operate un-
der
identical conditions, maintenance
and maintenance intervals will vary.
Experience is a valuable guide in de-
termining the best maintenance inter-
val for any one particular operation.
NOTE
A small amount of oil in the system
may
be normal and should not, in it-
self, be considered a reason to replace
the desiccant cartridge. Oil stained
desiccant can function adequately.
Every 900 operating hours or 25,000 miles
(40,000 km) or every 3 months check for
moisture in the air brake system by
opening air tanks, drain cocks, or valves
and checking for presence of water
.
A tablespoon of water found in the air tank
would point to the need for a desiccant
cartridge change. However, the following
conditions can also cause water
MAINTENANCE - Dual Air System Function Test
206 Y53-6113-1A1 (11/20)
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