Bendix Commercial Vehicle Systems AD-RP PuraGuard Oil Coalescing Remote Purge Air Dryers - Manual (Page 7)

7
For Bendix ® AD-RP ™ PuraGuard ® oil coalescing air
dryers only: Preventive Maintenance is as easy as 1-2-3
Adhering to a preventive maintenance schedule is
crucial to keeping a vehicle’s air system clean and to
help ensure superior performance of all components that
utilize system air — such as brakes, emissions equipment
and automated manual transmissions. Depending on
vocation, Bendix recommends a 1, 2 or 3-year air dryer
cartridge replacement on vehicles equipped with a Bendix
®
compressor.
For severe service application — such as residential refuse
trucks or school buses — the air dryer cartridge should be
replaced every year or every 100,000 miles. For pick-up
and delivery operations, or for double- and triple-trailer
line haul trucks, replacement is recommended every two
years or 200,000 miles. Line-haul operations using a single
trailer should swap the fi lter out every three (3) years or
300,000 miles. The recommended intervals for trucks
equipped with non-Bendix compressors are 6 months
(50,000 miles), one year (100,000 miles), and two years
(200,000 miles), respectively.
More frequent intervals may be required depending
on a vehicle’s age, its compressor condition, use of a
non-Bendix compressor, the operating environment, the
vehicle’s vocation, and its usage. In conjunction with these
guidelines, fl eets can determine the functionality of their
fi lters by checking for moisture in the air brake system
monthly. If moisture is present, the air dryer cartridge may
require replacement. Refer to the Bendix Service Data
Sheet of the specifi c air dryer for additional information.
This air dryer is intended to remove moisture and other
contaminants normally found in the air brake system.
Do not inject alcohol, anti-freeze, or other de-icing
substances into or upstream of the air dryer. Alcohol
is removed by the dryer, but reduces the effectiveness
of the device to dry air. Use of other substances can
damage the air dryer and may void the warranty.
OPERATION & LEAKAGE TESTS (ALSO SEE
VIDEO BW2327*)
1. Check for excessive leakage around the purge valve.
With the compressor in the loaded mode (compressing
air), apply a soap solution to the purge valve exhaust
port and observe that leakage does not exceed a
one (1) inch bubble in fi ve (5) seconds. If the leakage
exceeds the maximum specifi ed, service the purge
valve assembly.
2. Check for leakage around the desiccant cartridge. With
the compressor in loaded mode (compressing air),
apply a soap solution around the desiccant cartridge
seal and observe that no leakage occurs. If leakage is
noted, tighten the cartridge using a strap wrench and
re-test for leakage.
3. While observing the dash gauge(s), build up system
pressure at approximately 1,800 engine/compressor
rpm to governor cut-out. Note the pressure on the
dash gauge(s) at the moment governor cut-out occurs
and that the Bendix
® AD-RP ™ air dryer purges with
an audible escape of air. Observe the dash gauge(s)
pressure for two minutes after the purge cycle begins.
The front axle service (secondary) and the rear axle
(primary) reservoir pressures should not drop more
than 2 psi below the governor cut-out pressure noted.
Perform this test three times to positively confi rm the
values. If the pressure drop in the reservoirs exceeds
2 psi, check the air brake system for excessive leakage
and repair.
Build up system pressure to governor cut-out, wait a
minimum of 30 seconds for the purge cycle to complete,
then apply and release the service brakes to reduce
system air pressure to governor cut-in. Note that the
system once again builds to full pressure and is followed
by an Bendix AD-RP air dryer purge.
4. Check the operation of the heater and thermostat
assembly in the body during cold weather operation
(if possible) as follows:
A. Electric Power to the Heater and Thermostat
With the ignition or engine kill switch in the ON
position, check for voltage to the heater and
thermostat assembly using a voltmeter or test light.
Unplug the electrical connector at the air dryer and
place the test leads on each of the pins of the male
connector. If there is no voltage, look for a blown
fuse, broken wires, or corrosion in the vehicle wiring
harness. Check to see if a good ground path exists.
B. Thermostat and Heater Operation
Turn off the ignition switch and cool the body
assembly to below 40° F.
Note: If this test is performed in warm weather (above
30° F) it may be necessary to remove the heater and
thermostat assembly and cool it in a freezer.
Using an ohmmeter, check the resistance between the
electrical pins in the connector. The resistance should be
1.5 to 1.7 ohms for the 12 volt heater assembly and 6.0 to
6.9 ohms for the 24 volt heater assembly. If the resistance
is higher than the maximum stated, replace the heater and
thermostat assembly.
Warm the heater and thermostat assembly to over 90°F and
once again check the resistance. The resistance should
exceed 1000 ohms. If the resistance values obtained are
within the stated limits, the thermostat and heater assembly
is operating properly. If the resistance values obtained are
outside the stated limits, replace the heater and thermostat
assembly.
* Available through the Bendix Marketing Center on www.bendix.com