Bendix Commercial Vehicle Systems AD-RP PuraGuard Oil Coalescing Remote Purge Air Dryers - Manual (Page 6)

6
PREVENTIVE MAINTENANCE
Important: Review the warranty policy before performing
any intrusive maintenance procedures. An extended
warranty may be voided if intrusive maintenance is
performed during this period. Because no two vehicles
operate under identical conditions, maintenance and
maintenance intervals will vary. Experience is a valuable
guide in determining the best maintenance interval for any
one particular operation.
Every 900 operating hours; or every 25,000 miles or
three (3) months:
1. Check for moisture in the air brake system by opening
reservoirs, drain cocks or drain valves and checking
for the presence of water. If moisture is present,
the desiccant cartridge may require replacement;
however, the following conditions can also cause
water accumulation and should be considered before
replacing the desiccant:
A. An outside air source has been used to charge the
system. This air does not pass through the drying
bed.
B. Air usage is exceptionally high and not normal for
a highway vehicle. This may be due to accessory
air demands or some unusual air requirement that
does not allow the compressor to load and unload
(compressing and non-compressing cycle) in a
normal fashion. Check for high air system leakage.
If the vehicle vocation has changed, it may be
necessary to upgrade the compressor size. Refer
to Appendix A / Table A in this document. See the
column titled Vehicle Vocation.
C. The air dryer has been installed in a system that
has been previously used without an air dryer. The
system will be saturated with moisture and several
weeks of operation may be required to dry it out.
D. Location of the air dryer is too close to the air
compressor. Refer to Locating the Bendix ® AD-RP ™
Air Dryer On Vehicle section, plus Appendix A /
Table A/ column 2 for discharge line length.
E. In areas where more than a 30 degree range of
temperature occurs in one day, small amounts
of water can temporarily accumulate in the air
brake system due to condensation. Under these
conditions, the presence of small amounts of
moisture is normal and should not be considered
as an indication that the dryer is not performing
properly.
Note: A small amount of oil in the system is normal and
should not be considered as a reason to replace the
desiccant cartridge; oil-stained desiccant can function
adequately.
2. Visually check for physical damage to the AD-RP air
dryer such as a dented desiccant cartridge, chafed or
broken air and electrical lines, and broken or missing
parts.
3. Check mounting bolts for tightness. Re-torque to
50 lb-ft.
4. Perform the Operation & Leakage Tests listed in this
publication.
Every 3,600 operating hours, or every 100,000 miles
or twelve (12) months:
1. Test the AD-RP air dryer turbo cut-off and purge valves
for leakage. Disconnect the supply, control and delivery
lines from the AD-RP dryer. Perform the tests below in
the order they are presented.
A. Apply 120 psi shop air pressure to the control port
and a soap solution to the supply port. If leakage
exceeds a one (1) inch bubble in fi ve (5) seconds,
repair the turbo cut-off piston and valve before
proceeding to step 2.
B. With 120 psi shop air pressure applied to the control
port, apply a soap solution to the purge exhaust port.
If leakage exceeds a one (1) inch bubble in fi ve (5)
seconds, repair the purge piston and valve before
proceeding to step 2.
C. With 120 psi shop air pressure applied to the control
and supply port, apply a soap solution to the purge
exhaust port. If leakage exceeds a one (1) inch
bubble in fi ve (5) seconds, repair the turbo cut-off
piston and valve before proceeding to step 2.
D. With a plug installed in the delivery port, 0 psi in the
control port, and 120 psi applied to the supply port,
apply a soap solution to the purge exhaust port. If
leakage exceeds a one (1) inch bubble in fi ve (5)
seconds, repair the purge piston and valve before
proceeding to step 2.
2. Perform the Operation & Leakage Tests shown in this
publication.
Every 10,800 hours; or every 350,000 miles or 36
months:
1. Replace the air dryer desiccant cartridge.
Note: The desiccant change interval may vary from vehicle
to vehicle. Although typical desiccant cartridge life is three
years, many will perform adequately for a longer period of
time. In order to take maximum advantage of desiccant life
and ensure that replacement occurs only when necessary,
it is important that you perform the Operation & Leakage
Tests.
2. Perform the Operation & Leakage Tests shown in this
publication.