Navistar ProStar+, Operation And Maintenance Manual

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Maintenance Instructions
At least once a year, the entire brake system must be inspected
by a trained mechanic. Deteriorated components or components
worn outside of specifications must be replaced. Check:
1. Rubber components for condition, cracks, tears, wear,
missing components, etc.
2. Condition of drums, brake chambers, and slack
adjusters for wear, corrosion, maladjustment, cracks,
missing components, etc.
3. For air leaks. No air leakage is permissible. Also,
check for air leaks with parking brake disengaged and
wheels blocked.
4. Hose or pipes for rust, damage, deterioration.
5. Proper operation of service, parking, and trailer brake
controls.
6. The condition and full insertion of the ABS wheel speed
sensors, wiring, and connectors.
7. Proper ABS wheel speed sensor-to-exciter teeth gap.
Air Dryer
General Information
NOTE: The use of an air dryer does not eliminate the need
to periodically drain the air tanks.
The air dryer removes humidity (water), air compressor oil, and
dirt from the incoming compressed air, thus protecting the air
system against deterioration and restriction.
The air dryer is installed between the air compressor discharge
line and the air tanks. The air dryer has a desiccant cartridge
and a filter which is serviced as an assembly. Moisture from the
air collects on the desiccant and is automatically discharged.
Life and performance of the air dryer depends on usage, air
humidity levels, environmental temperatures, air compressor oil
control, and desiccant quantity. Regularly check the desiccant,
purge valve, and air dryer heater performance.
Desiccant Filter
Open reservoir drain valves and check for presence of water.
Small amounts of water due to condensation are normal. If the
wet, primary, or secondary tanks are collecting an abnormally
high amount of water between regular air tank drain intervals,
replace the air dryer desiccant.
The air dryer desiccant replacement interval may vary; it is
generally recommended that the desiccant be replaced every
12 months for small air dryers, like the Bendix
®
AD-IP
®
, or every
24 months for large air dryers, like the Bendix
®
AD-9
®
or Bendix
®
AD-IS ® . If experience has shown that extended or shortened life
has resulted for 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
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