Bendix Commercial Vehicle Systems AD-SP SYSTEM PURGE AIR DRYER 10/04 User Manual
®
Bendix® AD-IP® Integral Purge and AD-IP® PuraGuard® Oil Coalescing
Integral Purge Air Dryers
DESICCANT
CARTRIDGE
CABLE
MOUNTING
BRACKET
MOUNTING
CABLE
SD-08-2414
CONTROL
PORT
LOWER
MOUNTING
BRACKET
DELIVERY
PORT
PURAGUARD OIL
COALESCING AIR
DRYER LABEL
DISCHARGE
PURAGUARD® OIL
COALESCING AIR
DRYER MEDALLION
SAFETY VALVE
HEATER & THERMOSTAT
CONNECTOR
SUPPLY
PORT
Bendix® AD-IP® integral purge air dryer with the
PuraGuard® oil coalescing cartridge and the new
cable mounting bracket.
OLD STYLE
MOUNTING
EXTENDED
PURGE
PORT
SADDLE
BRACKET
FIGURE 1 - BENDIX® AD-IP® INTEGRAL PURGE AIR DRYERS
Standard Bendix AD-IP integral purge air dryer
shown with the old style saddle mounting bracket.
1
GENERAL SAFETY GUIDELINES
WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS
TO AVOID PERSONAL INJURY OR DEATH:
When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:
▲ Park the vehicle on a level surface, apply the
parking brakes and always block the wheels.
Always wear personal protection equipment.
▲ Stop the engine and remove the ignition key
when working under or around the vehicle.
When working in the engine compartment,
the engine should be shut off and the ignition
key should be removed. Where circumstances
require that the engine be in operation, EXTREME
CAUTION should be used to prevent personal
injury resulting from contact with moving,
rotating, leaking, heated or electrically-charged
components.
▲ Do not attempt to install, remove, disassemble
or assemble a component until you have read,
and thoroughly understand, the recommended
procedures. Use only the proper tools and
observe all precautions pertaining to use of those
tools.
▲ If the work is being performed on the vehicle’s
air brake system, or any auxiliary pressurized air
systems, make certain to drain the air pressure
from all reservoirs before beginning ANY work
on the vehicle. If the vehicle is equipped with a
Bendix
dryer reservoir module, or a Bendix
®
AD-IS® air dryer system, a Bendix® DRM™
®
AD-9si™ air
dryer, be sure to drain the purge reservoir.
▲ Following the vehicle manufacturer’s
recommended procedures, deactivate the
electrical system in a manner that safely removes
all electrical power from the vehicle.
▲ Never exceed manufacturer’s recommended
pressures.
▲ Never connect or disconnect a hose or line
containing pressure; it may whip. Never remove
a component or plug unless you are certain all
system pressure has been depleted.
®
▲ Use only genuine Bendix
brand replacement
parts, components and kits. Replacement
hardware, tubing, hose, ttings, etc. must be of
equivalent size, type and strength as original
equipment and be designed speci cally for such
applications and systems.
▲ Components with stripped threads or damaged
parts should be replaced rather than repaired.
Do not attempt repairs requiring machining or
welding unless speci cally stated and approved
by the vehicle and component manufacturer.
▲ Prior to returning the vehicle to service, make
certain all components and systems are restored
to their proper operating condition.
▲ For vehicles with Automatic Traction Control
(ATC), the ATC function must be disabled (ATC
indicator lamp should be ON) prior to performing
any vehicle maintenance where one or more
wheels on a drive axle are lifted off the ground
and moving.
▲ The power MUST be temporarily disconnected
from the radar sensor whenever any tests USING
A DYNAMOMETER are conducted on a Bendix
®
Wingman® Advanced™-equipped vehicle.
▲ You should consult the vehicle manufacturer's operating and service manuals, and any related literature,
in conjunction with the Guidelines above.
2
DESCRIPTION
The function of the Bendix® AD-IP® integral purge air
dryer — and the Bendix® AD-IP® integral purge air dryer
with PuraGuard® oil coalescing — is to collect and remove
air system contaminants in solid, liquid and aerosol form,
before they enter the brake system. They provide clean, dry
air to the components of the brake system which increases
the life of the system and reduces maintenance costs. Daily
manual draining of the reservoirs is eliminated.
The AD-IP and AD-IP PuraGuard oil coalescing air dryers
consist of a desiccant cartridge secured to a die cast
aluminum end cover with a single, central bolt. The end
cover contains a check valve assembly, safety valve,
heater and thermostat assembly, three pipe thread air
connections, optional extended purge port (plugged), and
the purge valve assembly. The removable purge valve
assembly incorporates the purge valve mechanism and
a turbo charger cut-off feature that is designed to prevent
loss of engine turbo-boost pressure during the purge cycle
of the air dryer. For ease of serviceability, all replaceable
assemblies can be replaced without removing the air dryer
from its mounting on the vehicle.
IMPORTANT
When servicing, note that standard Bendix AD-IP air
dryers, or air dryer cartridges, may be serviced with
PuraGuard® oil coalescing air dryer or cartridges, however,
PuraGuard (PG) oil coalescing air dryer or cartridges must
only be serviced with like replacements.
Sensitive downstream components such as automated
manual transmissions, diesel exhaust emission systems,
etc. can be damaged due to excessive oil levels. Therefore,
always replace a PG cartridge with a Bendix PG cartridge.
The AD-IP air dryer has three female pipe thread air
connections identied as follows:
Air Connection Function/Connection
CON 4 ...........................Control Port (purge valve control
& turbo cut-off).
SUP 11 ...........................Supply Port (air in).
DEL 2.............................Delivery Port (air out).
(Not Identied) ...............Extended Purge Port
The AD-IP PuraGuard oil coalescing air dryer has an
identical appearance to the standard AD-IP air dryer, but
contains a coalescing media at the inlet of the desiccant
bed. The coalescing media provides a higher level of
oil removal over the standard AD-IP air dryer. The ADIP PuraGuard oil coalescing air dryer has all the same
functions of the standard AD-IP air dryer and is used where
lower oil concentration levels are required. The AD-IP
PuraGuard oil coalescing air dryer can be identied by the
PuraGuard oil coalescing label shown in Figure 1 located
on the air dryer cartridge.
Early Bendix AD-IP air dryers included a “Drop In”
conguration for air systems that use either the Holset®
(Cummins®) Type E or QE air compressor. For information
pertaining to this conguration see the Bendix AD-IP Air
Dryer Troubleshooting Chart at the end of the manual.
3
Note 1:
The Bendix® AD-IP® air dryer and reservoir
system purge piston has a purge control
channel drain. This allows any condensation
in this area to ow past a diaphragm in the
top of the purge piston and out through a
channel in the middle of the central bolt of
the purge assembly to be drained. During
the purge cycle this drain is closed.
OIL
SEPARATOR
PURGE
ORIFICE
CONTROL
PORT
PURGE
CONTROL
LINE
SUPPLY
PORT
GOVERNOR
COMPRESSOR
FIGURE 2 - BENDIX® AD-IP® INTEGRAL PURGE AIR DRYER CHARGE CYCLE
ENGINE
TURBO
TURBO
CUT-OFF VALVE
EXHAUST
PURGE
VALVE
DESICCANT
BED
PURGE
VOLUME
DELIVERY
CHECK VALVE
DISCHARGE
PORT
OPERATION
GENERAL
Note: Unless otherwise stated in this manual, the Bendix®
AD-IP® air dryer refers to both the standard and Bendix
AD-IP® PuraGuard® oil coalescing air dryer. The AD-IP air
dryer alternates between two operational modes or “cycles”
during operation: the Charge Cycle and the Purge Cycle.
The following description of operation is separated into
these “cycles” of operation.
CHARGE CYCLE (Refer to Figure 2)
When the compressor is loaded (compressing air)
compressed air — along with oil, oil vapor, water and water
vapor — ows through the compressor discharge line to the
supply port of the air dryer body.
As air travels through the end cover assembly, its direction
of ow changes several times, reducing the temperature,
causing contaminants to condense and drop to the bottom
or sump of the air dryer end cover.
After exiting the end cover, the air ows into the desiccant
4
®
cartridge. Once in the desiccant cartridge the air rst ows
through an oil separator, located between the outer and
inner shells of the cartridge. The separator removes water
in liquid form as well as liquid oil and solid contaminants.
Air, along with the remaining water vapor, is further cooled
as it exits the oil separator and continues to ow upward
between the outer and inner shells. Upon reaching the top
of the cartridge the air reverses its direction of ow and
enters the desiccant drying bed. Air owing down through
the column of desiccant becomes progressively drier as
water vapor adheres to the desiccant material in a process
known as “ADSORPTION.” The desiccant cartridge using
the adsorption process typically removes most of the water
vapor from the pressurized air.
Dry air exits the bottom of the desiccant cartridge and ows
through the center of the bolt used to secure the cartridge
to the end cover. Air ows down the center of the desiccant
cartridge bolt, through a cross drilled passage and exits
the air dryer delivery port through the delivery check valve.
PURGE
CONTROL
LINE
GOVERNOR
COMPRESSOR
SEPARATOR
PURGE
ORIFICE
CONTROL
PORT
SUPPLY
PORT
ENGINE
TURBO
OIL
TURBO
CUT-OFF VALVE
EXHAUST
DESICCANT
BED
PURGE
VOLUME
DELIVERY
CHECK VALVE
DISCHARGE
PORT
PURGE
VALVE
FIGURE 3 - BENDIX® AD-IP® INTEGRAL PURGE AIR DRYER PURGE CYCLE
Note: the early end cover designs incorporated a vertical
delivery check valve while the newer versions have a
horizontal check valve. Both have the same function, but
the components are not interchangeable. See Figure 4.
A small amount of the air owing through the center of the
desiccant cartridge bolt ows out the cross drilled purge
orice and into the purge volume, for regenerating the
desiccant. The air dryer will remain in the charge cycle
until the air brake system pressure builds to the governor
cut-out setting.
PURGE CYCLE (Refer to Figure 3)
As air brake system pressure reaches the cut-out setting
of the governor, the governor unloads the compressor (air
compression is stopped) and the purge cycle of the air
moves in response to air pressure causing the purge
valve to open to the atmosphere and the turbo cut-off
valve to close off the supply of air from the compressor
(this will be further discussed in the Turbo Cut-off Feature
section). Water and contaminants in the end cover sump
are expelled immediately when the purge valve opens.
Also, air which was owing through the desiccant cartridge
changes direction and begins to ow toward the open purge
valve. Liquid oil and solid contaminants collected by the oil
separator are removed by air owing from the purge volume
through the desiccant drying bed to the open purge valve.
The desiccant cartridge decompression lasts only a few
seconds and is evidenced by an audible burst of air at the
AD-IP air dryer exhaust. No purging of air should occur
after 30 seconds.
dryer begins. When the governor unloads the compressor,
it pressurizes the compressor unloader mechanism and the
line connecting the governor unloader port to the Bendix
®
AD-IP
air dryer end cover control port. The purge piston
®
5
DESICCANT
BED
OIL
SEPARATOR
DESICCANT
CARTRIDGE
PURGE
ORIFICE
PURGE
CONTROL
PORT
SUPPLY
PORT
TURBO
CUT-OFF
VALVE
PURGE
VALVE
CARTRIDGE
BOLT
DELIVERY
VOLUME
CHECK
VALVE
(BLACK)
PORT
Old Style End Cover -Vertical Delivery Check Valve
FIGURE 4 - BENDIX® AD-IP® AIR DRYER SECTIONAL VIEW
SPRING
PIPE PLUG
DELIVERY
CARTRIDGE
BOLT
CHECK VALVE
(WHITE)
O-RING
New Style End Cover - Horizontal Delivery Check Valve
PORT
The actual reactivation of the desiccant drying bed begins
as dry air ows from the purge volume through the purge
orice in the desiccant cartridge bolt, then through the
center of the bolt and into the desiccant bed. Pressurized
air from the purge volume expands after passing through
the purge orice; its pressure is lowered and its volume
increased. The ow of dry air through the drying bed
CONTROL
PORT
SUPPLY
PORT
TURBO
CUT-OFF
VALVE
PURGE
VALVE
reactivates the desiccant material by removing the water
vapor adhering to it. Generally 30 seconds are required for
the entire purge volume of a standard Bendix® AD-IP® air
dryer to ow through the desiccant drying bed.
The delivery check valve assembly prevents air pressure in
the brake system from returning to the air dryer during the
purge cycle. After the 30 second purge cycle is complete
the desiccant has been reactivated or dried. The air dryer
is ready for the next charge cycle to begin. However the
purge valve will remain open and will not close until air
brake system pressure is reduced and the governor signals
the compressor to charge the system.
TURBO CUT-OFF FEATURE (Refer to Figure 5)
The primary function of the turbo cut-off valve is to
prevent loss of engine turbocharger air pressure through
the AD-IP air dryer in systems where the compressor
intake is connected to the engine turbocharger. The turbo
cut-off valve also removes the “pufng” of air out the open
purge exhaust when a naturally aspirated, single cylinder
compressor, equipped with an inlet check valve, is in use.
FIGURE 5 - AD-IP® INTEGRAL PURGE AIR DRYER TURBO
CUT-OFF
6
3 O-RING
GROOVES
2 O-RING
GROOVES
PURGE VALVE
HOUSING
STANDARD
PURGE VALVE
FIGURE 6 - BENDIX® AD-IP® AND AD-IP DLU AIR DRYER PURGE VALVES
At the onset of the purge cycle, the downward travel of
the purge piston is stopped when the turbo cut-off valve
(tapered portion of purge piston) contacts its mating metal
seat in the purge valve housing. With the turbo cut-off valve
seated (closed position), air in the compressor discharge
line and Bendix® AD-IP® air dryer inlet port cannot enter
the air dryer. In this manner the turbo cut-off effectively
maintains turbocharger boost pressure to the engine.
DISCHARGE LINE UNLOADER (Refer to Figure 6)
The Bendix AD-IP air dryers are available as a standard air
dryer and as a Discharge Line Unloader (DLU-style) . The
functions of these air dryers (Standard vs. DLU) and their
internal components are different. The standard air dryer
cuts off the supply air from compressor to the air dryer
when the compressor is in the unloaded mode, while the
DLU air dryer utilizes a purge valve to bleed off the excess
air instead of unloading the compressor. Externally the
standard and DLU versions of each air dryer conguration
are identical in appearance; however the DLU-style air
dryer often has a silencer on the exhaust port.
For Bendix AD-IP air dryers: 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 ensuring
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 applications — such as residential
refuse trucks or school buses — the air dryer cartridge
should be replaced every year or 100,000 miles; for pick-
up and delivery operations, or for double- and triple-trailer
line haul trucks, every two years or 200,000 miles is the
recommendation. Line-haul operations using a single trailer
should swap the 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.
PREVENTIVE MAINTENANCE
More frequent intervals may be required depending
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. Note: It is acceptable for
the purge valve to be maintained as necessary, i.e., the
installation of a purge valve maintenance kit, without
voiding the warranty.
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.
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, eets can determine the functionality of their
lters by checking for moisture in the air brake system
monthly. If moisture is present, the air dryer cartridge may
require replacement. Reference the Bendix Service Data
Sheet of the specic air dryer for additional information.
(Recommended intervals for trucks equipped with nonBendix compressors are 6 months (50,000 miles), one
year (100,000 miles) and two years (200,000 miles),
respectively.)
DLU
PURGE VALVE
7
Notes:
1. Visually check for physical damage to the air dryer
such as chaffed or broken air and electrical lines and
broken or missing parts.
2. Check mounting bolts for tightness. Re-torque to
270–385 in-lbs.
3. Perform the Operation & Leakage Tests listed in this
publication.
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
1. Install a pressure gauge in the #1 reservoir. Check
all lines and ttings leading to and from the air dryer
for leakage and integrity. Test the delivery port check
valve assembly by building the air system to governor
cut-out and observing a test air gauge installed in the
#1 reservoir. Note the pressure on the air gauge after
governor cut-out pressure is reached, a rapid loss of
pressure could indicate a failed delivery port check
valve. This can be conrmed by shutting the engine off,
draining the air brake system pressure to a point below
governor cut-in (typically < 95 psi). Make sure the dryer
has completed the purge cycle (wait 30 seconds after
governor cut-out) and determine if there is any air ow
out of the air dryer purge valve. If air ow is detected
at the purge valve, the air dryer delivery check valve
should be serviced. Remove the test gauge before
returning the vehicle to service.
2. Check for excessive leakage around the purge valve.
With the compressor in 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 one (1) second. If the leakage
exceeds the maximum specied, repair the purge valve
assembly.
3. Make sure all reservoir drain cocks are closed. Build
up system pressure to governor cut-out and note that
Bendix® AD-IP® air dryer purges with an audible escape
of air. 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 AD-IP air dryer purge.
4. Check the operation of the end cover heater and
thermostat assembly during cold weather operation as
follows:
A. Electric Power to the Dryer
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 connector with the locking latch. 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
Note: These tests are not required except in cold
weather operation.
Turn off the ignition switch and cool the thermostat
and heater assembly to below 35° F. Using an
ohmmeter, check the resistance between the
electrical pins in the air dryer connector half. The
resistance should be 1.5 to 3.0 ohms for the 12 volt
heater assembly and 6.0 to 9.0 ohms for the 24 volt
heater assembly.
Warm the thermostat and heater assembly to
over 90° F. and 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.
REBUILDING THE BENDIX® AD-IP® AIR
DRYER
GENERAL
If, after completing the routine operation and leakage tests,
it has been determined that one or more components of
the air dryer requires replacement or maintenance, refer to
the Bendix Quick Reference Catalog (BW1114), available
on w ww.bendix.com, for the latest maintenance kits and
service parts.
When rebuilding or replacing components of the air dryer
use only genuine Bendix® service parts.
BENDIX AD-IP AIR DRYER REMOVAL
This air dryer removal process is presented in the event
it becomes necessary to replace the entire air dryer.
Normal service and parts replacement does not require
removal of the air dryer from the vehicle.
1. Park the vehicle on a level surface and prevent
movement by means other than the brakes.
8
Maintenance Kits
Description
Cartridge Bolt Kit 109498
Desiccant Cartridge Service New 065624
Desiccant Cartridge Remanufactured 109493X
Bendix® PuraGuard® Coalescing Cartridge Kit Service New
PuraGuard Coalescing Cartridge Kit Reman Exchange
Delivery Check Valve Kit 109494
Exhaust Cover Kit 5011327
Extended Purge Kit 3/8" U-Bolt; 90in3 Reservoir 5012561N
Extended Purge Kit 3/8" U-Bolt; 288in3 Reservoir 5008972N
Extended Purge Kit 1/2" U-Bolt; 90in3 Reservoir 5005309N
12 Volt Heater & Thermostat Kit 109495
24 Volt Heater & Thermostat Kit 109496
Mounting Bracket Kit 5001247
Silencer Kit K021189
Wiring Harness & Splicing Kit 109871N
Purge Valve Maintenance Kits
Purge Valve
Assembly Type
Purge Valve Assembly
Kit for climate conditions
above -40°C (-40°F)
Arctic Purge Valve
Assembly Kit for climate
conditions between
-40°C to -50°C
(-40°F to -58°F)
Purge Valve Assembly
Kit for climate conditions
above -40°C (-40°F)
Arctic Purge Valve
Assembly Kit for climate
conditions between -40°C
to -50°C (-40°F to -58°F)
Conguration /
Installation
Bendix® AD-IP® Air Dryer K022105
Bendix® AD-IP
EverFlow® Air Dryer
Module
AD-IP Drop-In
Air Dryer
AD-IP Air Dryer K031559
AD-IP EverFlow
Air Dryer Module
AD-IP Drop-In Air Dryer
Bendix® AD-IP® Air Dryer
Discharge Line Unloader
AD-IP Air Dryer Discharge
Line Unloader
®
Piece
Number
065624PG
109493PGX
Piece
Number
K031560
K031561
K031562
K031563
HEATER &
THERMOSTAT
CONNECTOR
AD-IP® AIR
DRYER END
COVER
LOCKING LATCH
(MUST BE INSERTED UNTIL IT
SNAPS OVER THE MATING CONNECTOR
ON AD-IP® AIR DRYER
SIDE VIEW
WEATHERPROOF
ACCORDIAN
TOP VIEW
SEAL
A two lead wire harness with attached weather resistant
connector is available as a service part. One of the two
leads is connected to the engine “kill switch” or ignition while
the other must be connected to a good vehicle ground. A
fuse is installed in the lead carrying vehicle power; install
a 10 amp fuse for the 12 volt heater and a 5 amp fuse for
the 24 volt heater.
Use 14 AWG wire if it is necessary to lengthen the wire
harness leads. Make certain all splices are weatherproofed.
Tie wrap or support all electrical wires leading to the AD-IP
air dryer.
FIGURE 7 - BENDIX® AD-IP® AIR DRYER HEATER AND
THERMOSTAT CONNECTOR
2. Drain all reservoirs to 0 psi. Compressor discharge
line may still contain residual pressure.
3. Identify and disconnect the three air lines from the end
cover and note the position of end cover ports relative
to the vehicle.
4. Unplug the vehicle wiring harness from the heater
and thermostat assembly connector on the end cover
assembly.
5. Remove the four bolts that secure both the upper and
lower mounting brackets to the vehicle, and remove
the air dryer from the vehicle.
9
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