Chevrolet Silverado 4500HD 2022 Owner's Manual page 363

The air dryer desiccant replacement interval
may vary; it is generally recommended that
the desiccant be replaced every 24 months.
If experience has shown that extended or
shortened life has resulted following a
particular installation, then the interval
should be increased or reduced accordingly.
Purge Valve
Check that the purge valve opens and expels
moisture when the air governor shuts off
the air compressor. Air should escape rapidly
and then quickly stop. If the purge valve
does not open, or you can hear a slight
audible air leakage past the valve for longer
than 30 seconds, the valve may be sticking
and should be rebuilt. Purge valves may also
stick if the air dryer heater has failed and
ice is clogging the valve.
Heater
Check that the air dryer heater activates at
temperatures below freezing. With the
vehicle in a cold environment and before the
engine is started, turn on the vehicle and
touch the air dryer housing. It should be
warmer than other metallic items on the
vehicle. If some warmth cannot be felt, it
may indicate that the heater element or the
wiring powering it should be serviced.
Steering
General Information
Warning
To prevent property damage, personal
injury, and/or death, always follow
recommended procedures for steering
system maintenance. Maintain the
steering system in proper condition;
otherwise, reduced steering ability could
result.
Have a technician examine the steering
mechanism. Minor adjustments could
head off further problems.
Check tie rod ends, drag link ends, and
kingpins. Joints and fasteners must be
tight. Articulating joints must be well
lubricated.
Check for installation and spread of cotter
pins and tightness of nuts at both ends of
the tie rod and drag link.
Maintain proper power steering fluid
levels.
Service and Maintenance
Check that pitman arm (steering arm at
steering gear) mounting is tight and
locked. Check system for leaks or hose
chafing.
Regularly inspect steering column joint
bolts and steering linkage, particularly for
body-to-chassis clearance.
Have any steering problems corrected at
once by a qualified service technician.
Tightening Steering Intermediate Shaft Joint
Bolts
As a good maintenance practice, it is
recommended that steering intermediate
shaft joint bolts be checked for tightness
every 193 000 km (120,000 mi) or annually,
whichever occurs first.
Lubrication Points
The steering shaft is lubricated at three
points. For the correct maintenance interval,
see Maintenance Schedule 0 330.
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