operators_manual

Maintenance
CAUTION
Replace oil-coalescing desiccant air
dryer cartridge every 1 year regardless
of mileage. Only use oil-coalescing
desiccant replacement cartridge when
replacing. Failure to perform this main-
tenance task will void the PACCAR
Transmission warranty and may result
in expensive transmission damage.
Replace (non-oil-coalescing) desiccant
cartridge:
• On-highway operation replace
every 2-3 years, 350,000 miles
(560,000 km) or 10,800 hours.
• High duty cycle usage such as
transit bus, refuse hauler, dump
truck, cement mixers and off-
highway operation replace every 1
year, 100,000 miles (160,000 km)
or 3,600 hours.
NOTE
Review the warranty policy before per-
forming any maintenance procedures.
An extended warranty may be voided
if unauthorized maintenance is per-
formed during this period.
Bendix® AD-HF Series Air Dryer
Your vehicle may be equipped with a
Bendix® AD-HF series air dryer. Any air
dryer replacement should be made with an
identical component.
WARNING
Use of an air dryer brand or model that
differs from what was originally instal-
led could cause the air system to not
perform correctly unless the full air
system design is reviewed and modifi-
cations are made to comply with Fed-
eral Motor Vehicle Safety Standard
(FMVSS) 121 Air Brake Systems. Fail-
ure to abide by this warning and main-
tain compliance with FMVSS 121
could cause loss of vehicle control and
may lead to serious personal injury or
death.
The AD-HF Series air dryer has
incorporated into its design various
components that have typically been
installed separately on the vehicle (see
below for components/areas affected):
• Pressure protection valves
• Safety valve
• Solenoid valves and plumbing
• Plumbing of the front and rear
service air tanks
• Plumbing to accessory systems
These components are required to meet
the Federal Motor Vehicle Safety
Standards (FMVSS 121 - Air Brake
Systems). As the Warning above states,
any other type of air dryer installed in the
place of an AD-HF Series will require
changes, modifications and/or additions to
your vehicle’s air system to maintain
compliance with FMVSS 121.
MAINTENANCE - Air Dryer Maintenance
Y53-6126-1A1 (01/21) 235
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