Bendix Commercial Vehicle Systems AD-9 AND AD-9 IPC AIR DRYERS 4/11 User Manual

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Page 1

Bendix® AD-9® and AD-9® IPC (Integrated PuraGuard® Coalescing) Air Dryers

EXTENDED

PURGE

IPC AIR DRYER LABEL

OUTER

SHELL

END COVER

STANDARD

SD-08-2412

SUPPLY

CONTROL

PORT

WIRING HARNESS

DELIVERY PORT

FIGURE 1 - BENDIX

AD-9® AND AD-9® IPC AIR DRYER MODELS

CONNECTION

CHECK

VALVE

ASSEMBLY

END COVER

DESCRIPTION

The function of the Bendix® AD-9® and AD-9® IPC Integrated PuraGuard® Coalescing air dryers is to collect and remove air system contaminants in solid, liquid, and vapor 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.

PORT

PURGE VALVE

SAFETY VALVE

The Bendix AD-9 and AD-9 IPC Integrated PuraGuard Coalescing air dryers consists of a desiccant cartridge and a die cast aluminum end cover secured to a cylindrical steel outer shell with eight cap screws and nuts. The end cover contains a check valve assembly, a safety valve, three threaded air connections, and the purge valve housing assembly. The removable purge valve housing assembly incorporates a purge valve mechanism and a turbocharger cut-off feature that is designed to prevent loss

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DESICCANT CARTRIDGE



CHECK

VALVE



ORIFICE



GOVERNOR



COMPRESSOR



RESERVOIR

ENGINE

TURBO



CONTROL

PORT



SUPPLY

PORT



DESICCANT

BED

OIL

SEPARATOR



PURGE

VALVE



EXHAUST







HEATER

ELEMENT



SUMP



DELIVERY

PURGE

VOLUME

CHECK

VALVE

ASSEMBLY

PORT

FIGURE 2 - BENDIX

AD-9® AND AD-9® IPC AIR DRYER CHARGE CYCLE

of engine “turbo” boost pressure during the purge cycle of the Bendix® AD-9® and AD-9® IPC air dryers. For ease of serviceability , the desiccant cartridge and discharge check valve assembly are screw-in type. The purge valve housing assembly – which includes the heater and thermostat assembly – and the discharge check valve assembly are serviceable from the exterior of the air dryer, while servicing the screw-in desiccant cartridge requires removal of the air dryer assembly from the vehicle.

The AD-9 IPC air dryer appears identical to the standard AD-9 air dryer, but contains a coalescing media at the inlet of the desiccant bed. This coalescing media provides a higher level of oil removal over the standard AD-9 air dryer. The AD-9 IPC air dryer has all the same functions of the standard AD-9 air dryer, and is used where oil is contaminating downstream components. The Bendix AD-9 IPC air dryer can be identiﬁ ed by the IPC label (shown in Figure 1), located on the air dryer housing.

The Bendix AD-9 and AD-9 IPC air dryers have three female pipe thread air connections and each is identiﬁ ed as follows:

Port l.D. Function/Connection

CON 4................Control Port

(purge valve control and turbo cut-off)

SUP 11 .............Supply Port (air in)

DEL 2 ...............Delivery Port (air out)

OPERATION OF THE BENDIX AD-9 AIR DRYER

The AD-9 and AD-9 IPC air dryers alternate 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 – ﬂ ows through the compressor discharge line to the supply port of the air dryer end cover. As air travels through the end cover assembly, its direction of flow

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DESICCANT

CARTRIDGE



CHECK

VALVE



ORIFICE



GOVERNOR



COMPRESSOR



RESERVOIR



ENGINE

TURBO

CONTROL

PORT



SUPPLY

TURBO

CUT-OFF

PISTON

DESICCANT

BED

OIL

SEPARATOR



PORT

PURGE

VALVE



EXHAUST







HEATER

ELEMENT



SUMP



PURGE

VOLUME



CHECK

VALVE

ASSEMBLY

DELIVERY

PORT

FIGURE 3 - BENDIX®AD-9® AND AD-9® IPC AIR DRYER PURGE CYCLE

changes several times, reducing the temperature, causing contaminants to condense and drop to the bottom, or sump,

The air dryer will remain in the charge cycle until air brake system pressure builds to the governor cut-out setting.

of the air dryer end cover.

PURGE CYCLE (Refer to Figure 3)

After exiting the end cover, the air ﬂ ows into the desiccant cartridge. Once in the desiccant cartridge, air ﬁ rst ﬂ ows through an oil separator which removes water in liquid form as well as oil and solid contaminants.

Air exits the oil separator and enters the desiccant drying bed. Air ﬂ owing 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 95% of the water vapor from the pressurized air.

The majority of dry air exits the desiccant cartridge through its integral single check valve to ﬁ ll the purge volume between the desiccant cartridge and outer shell. Some air will also exit the desiccant cartridge through the purge oriﬁ ce adjacent to the check valve.

Dry air ﬂ ows out of the purge volume through the single check valve assembly and out the delivery port to the ﬁ rst (supply) reservoir of the air system.

When air brake system pressure reaches the cut-out setting of the governor, the compressor unloads (air compression stopped), and the purge cycle of the air dryer begins. When the governor unloads the compressor, it pressurizes the compressor unloader mechanism and line connecting the governor unloader port to the air dryer end cover control port. The purge piston moves in response to air pressure, causing the purge valve to open to atmosphere and (partially) closing off the supply of air from the compressor . (This will be further discussed in the section covering the turbo cut-off feature.) Contaminants in the end cover sump are expelled immediately when the purge valve opens. Also, air – which was ﬂ owing through the desiccant cartridge – changes direction and begins to ﬂ ow toward the open purge valve. Oil and solid contaminants collected by the oil separator are removed by air ﬂ owing from the desiccant drying bed to the open purge valve.

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UPPER

BRACKET

STRAP

UPPER

BRACKET



PURGE

VALVE



DISCHARGE

LINE

CHECK

VALVE

ASSEMBLY



SUPPLY

PORT

TURBO

CUT-OFF

PISTON

FIGURE 4 - BENDIX® AD-9® AND AD-9® IPC AIR DRYER TURBO CUT-OFF



EXHAUST



The initial purge and desiccant cartridge decompression lasts only a few seconds and is evidenced by an audible burst of air at the Bendix® AD-9® or AD-9® IPC air dryer exhaust.

The actual reactivation of the desiccant drying bed begins as dry air ﬂ ows from the purge volume through the desiccant cartridge purge oriﬁ ce and into the desiccant drying bed. Pressurized air from the purge volume expands after passing through the purge oriﬁ ce; its pressure is lowered and its volume increased. The ﬂ ow of dry air through the drying bed reactivates the desiccant material by removing the water vapor adhering to it. Generally 15–30 seconds are required for the entire purge volume of a standard Bendix AD-9 or AD-9 IPC air dryer to ﬂ ow through the desiccant drying bed.

The end cover single 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 air dryer is ready for the next charge cycle to begin.

The purge valve will remain open after the purge cycle is complete, and will not close until air brake system pressure is reduced and the governor signals the compressor to charge.

TURBO CUT-OFF FEATURE (Refer to Figure 4)

The primary function of the turbo cut-off valve is to prevent loss of engine turbocharger air pressure through the Bendix AD-9 and AD-9 IPC air dryers in systems where the compressor intake is connected to the engine turbocharger. The turbo cut-off valve also reduces the “pufﬁ ng” of air out

DESICCANT CARTRIDGE

DESICCANT

BED

OIL

SEPARATOR

CONTROL

PORT

SUPPLY

PORT

TURBO

CUT-OFF

PISTON

FIGURE 5 - BENDIX® AD-9® AND AD-9® IPC AIR DRYER CROSS SECTION

PURGE VALVE

HOUSING

ASSEMBLY

PURGE

VALVE

HOUSING

LOWER

BRACKET

CHECK

VALVE

ASSEMBLY

DISCHARGE

PORT

the open exhaust when a naturally aspirated, single cylinder compressor equipped with an inlet check valve is in use.

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 discharge line and air dryer inlet port is restricted from entering the air dryer. While the turbo cut-off effectively prevents loss of turbocharger boost pressure to the engine, some “seepage” of air may be detected under certain conditions of compressor engine and turbocharger operation. Even so, there will always be low pressure trapped in the discharge line.

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. 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.

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Every 900 operating hours or 25,000 miles or every three (3) months:

1. Check for moisture in the air brake system by opening reservoirs, drain cocks, or valves and checking for presence of water. If moisture is present, the desiccant may require replacement; however, the following conditions can also cause water accumulation and should be considered before replacing the desiccant:

An outside air source has been used to charge the

system. This air did 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 and the column titled Vehicle Vocation.

C. The air dryer has been installed in a system that

has been previously used without an air dryer. This type of 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 the Locating Bendix® AD-9® and AD-9® IPC Air Dryer On Vehicle section and Appendix A, Table A, column 2 for discharge line length; or

E. In areas where more than a 30 degree range of

temperature occurs in one day, small amounts of water can 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 may be normal

and should not, in itself, be considered a reason to replace the desiccant; oil stained desiccant can function adequately.

2. Check mounting bolts for tightness. Re-torque to 270–385 inch pounds.

3. Perform the Operation & Leakage Tests listed in this publication.

AD-9® / AD-9® IPC

AIR DRYER

END COVER

A two lead, 12 inch, wire harness with attached weather resistant connector is supplied with all retroﬁ t and replacement Bendix Connect one of the two leads of the wire harness to the engine kill or ignition switch. The remaining lead of the wire harness must be connected to a good vehicle ground. A fuse should be installed in the power carrying wire; install a 10 amp fuse for 12 volt heaters and a 5 amp fuse for a 24 volt heater. Use 14 AWG wire if it is necessary to lengthen the wire harness provided. Make certain all wire splices are waterproofed. Tie wrap or support all electrical wire leading to the AD-9® or AD-9® IPC air dryer.

FIGURE 6 - HEATER AND THERMOSTAT CONNECTOR

LOWER

MOUNTING

BRACKET

FEMALE

CONNECTOR

MALE

CONNECTOR

LATCH MUST BE

INSERTED UNTIL

IT SNAPS OVER

TAB ON MATING

CONNECTOR

SIDE VIEW END VIEW

AD-9® and AD-9® IPC air dryers.

water or oil in downstream reservoirs indicate an AD-9® IPC air dryer desiccant cartridge may need to be replaced.

Every 10,800 hours; 300,000 miles or 36 months:

1. Rebuild the air dryer including the 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 assure that replacement occurs only when necessary , it is important that Operation & Leakage T ests be performed.

Oil removal requirements for air brake quality vary by vehicle manufacturer. Because vehicle vocation and maintenance can inﬂ uence when the AD-9® IPC air dryer cartridge requires replacement, each ﬂ eet should modify their replacement schedule based on experience. The change out interval will be extended if the compressor passes a low level of particles, and the interval will be reduced if excessive carbon particles are delivered to the dryer inlet. Higher compressor build up times at idle and

WARNING!

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.

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OPERATION & LEAKAGE TESTS

1. Test the outlet port check valve assembly by building the air system to governor cut-out and observing a test air gauge installed in the #1 reservoir. A rapid loss of pressure could indicate a failed outlet port check valve. This can be conﬁ rmed by bleeding the system down and removing the check valve assembly from the end cover. Once this has been done, subject air pressure to the unit and apply a soap solution to the check valve side. Leakage should not exceed a 1” bubble in 1 second.

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 housing assembly exhaust port and observe that leakage does not exceed a 1” bubble in 1 second. If the leakage exceeds the maximum speciﬁ ed, service the purge valve housing assembly.

3. Close all reservoir drain cocks. Build up system pressure to governor cut-out and note that the air dryer purges with an audible escape of air. “Fan” 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 air dryer purge.

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4. Check the operation of the safety valve by pulling the exposed stem while the compressor is loaded (compressing air). There must be an exhaust of air while the stem is held and the valve should re-seat when the stem is released.

5. Check all lines and ﬁ ttings leading to and from the air dryer for leakage and integrity.

6. 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 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 end cover

assembly to below 40 degrees Fahrenheit. Using an ohmmeter, check the resistance between the electrical pins in the female connector. The resistance should be 1.5 to 3.0 ohms for the 12 volt heater assembly and 6.8 to 9.0 ohms for the 24 volt heater assembly.

Some early models of the Bendix

AD-9® air dryer will have resistance readings of 1.0 to 2.5 ohms for the 12 volt heater assembly and 4.8 to 7.2 ohms for the 24 volt heater assembly. If the resistance is higher than the maximum stated, replace the purge valve housing assembly, which includes the heater and thermostat assembly.

Warm the end cover assembly to over 90 degrees

Fahrenheit 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 purge valve housing assembly, which includes the heater and thermostat assembly.

REBUILDING THE BENDIX® AD-9® AND AD-9® IPC AIR DRYERS

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 maintenance kit listing in this manual or the Bendix Reference Catalog (BW1 1 14) for complete kit information.

When rebuilding or replacing components of the air dryer, use only genuine Bendix parts. For ease in servicing the Bendix® AD-9® and AD-9® IPC air dryer desiccant cartridge assemblies, it is recommended that the air dryer be removed from the vehicle.

The kit illustrations on the following pages show the kit contents and will be referenced throughout the rebuilding procedures.

BENDIX® AD-9® AND AD-9® IPC AIR DRYER REMOVAL

1. Park the vehicle on a level surface and prevent movement by means other than the brakes.

2. Drain all reservoirs to 0 psi (0 kPa). — Caution: 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. See Figure 1.

4. Unplug the vehicle wiring harness from the heater and thermostat assembly connector on the purge valve housing assembly. See Figure 6.

5. Loosen the 5/16" hex cap screw and sleeve nut securing the upper mounting strap to the upper mounting bracket. See Figure 7, illustration A.

Some air dryers may contain a one piece upper

mounting strap as shown in Figure 7, illustration B. If this is type of strap is present, loosen the adjustment locknut and remove the strap and isolator from the upper bracket.

6. Mark and remove the two 3/8" end cover cap screws, locknuts, and four special washers that secure the lower mounting bracket to the end cover. Also be sure to mark these two holes of the end cover. (These bolts are longer than the other 6 bolts.) Retain the mounting hardware. See Figure 7, illustrations A and B.

7. Remove the air dryer from the vehicle.

Quick

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MAINTENANCE KITS

Service New (S) Kit Part Number

107695 S – – –

or Reman

Exchange (RX)

Purge

Valve Type Heater

Connector

Color Kit Description Illustration

Complete Mounting Bracket Kit - Contains the upper and lower brackets as well as the necessary mounting hardware.

5002080 S – – – 5009610 S – – –

107799 S – – –

107800N S – – –

5005037 S Hard Seat – –

5005893 S Soft Seat – –

K041395 S – – – Universal Check Valve Kit E 5003838 S – – – Exhaust Cover Kit F

5004224N S – – – Silencer Kit G

107796 S – – –

107794X RX – – –

K028830 S – – –

109960 S – – –

109961 S – – – Adaptor Kit 800405 S Soft Seat 12V-75W White

5004338 S Soft Seat 24V-75W Gray 5004341X RX Soft Seat 12V-75W White 5004342X RX Soft Seat 24V-75W Gray

5004479 S Hard Seat 12V-75W White

5004480 S Hard Seat 24V-75W Gray

5004381 S Hard Seat 24V-100W Yellow

5004339 S DLU 12V-75W White

5004340 S DLU 24V-75W Gray

5006580 S DLU 24V-100W Yellow

See Catalog

BW1114

109578 S – 12V-75W White 109579 S – 24V-75W Gray

5002595 S – 24V-100W Yellow

109871N S – – – Heater Electrical Splicing Kit M

113209 S – – – Universal Mounting Plate N

S and RX – – – End Cover Replacement K

Mounting Kit B End Cover Check Valve Assembly Replacement -

3/4 inch thread size.

End Cover Check Valve Assembly Replacement -

1/2 inch thread size.

Purge Valve Housing Maintenance Kit - Contains the parts necessary to rebuild the air portion of the purge valve housing and does not include the heater and thermostat.

Desiccant Cartridge Replacement Kit - Contains the parts necessary to change the desiccant cartridge only. Non-IPC Air Dryer

Desiccant Cartridge Replacement Kit - Contains the parts necessary to change the desiccant cartridge only. IPC Air Dryer

Makeup Line Kit

Purge Valve Housing Assembly

(w/heater and thermostat)

Heater and Thermostat Kit L

I5000457 S – – –

Page 9

SLEEVE

NUT

MOUNTING

SADDLE

LOCKNUT

MOUNTING

STRAP

5/16" HEX

HEAD SCREW

MOUNTING STRAP

ISOLATOR

UPPER BRACKET

ADJUSTING NUT

SPECIAL

WASHER

LOWER

MOUNTING

BRACKET

SPECIAL WASHER

3/8" END

COVER CAP

SCREW

STANDARD MOUNTING BRACKET KIT

SPECIAL

WASHER

3/8" END COVER

CAP SCREW

LOCKNUT

LOWER

MOUNTING

BRACKET

SPECIAL

WASHER

MOUNTING BRACKET KIT

SMALL O-RING

MEDIUM O-RING

LARGE O-RING

QUAD RING

DELIVERY CHECK

VALVE PLUG

(NOT INCLUDED

IN KIT)

SPRING

CHECK VALVE

O-RING

CHECK

VALVE

CHECK VALVE

MAINTENANCE KIT

PURGE VALVE

ASSEMBLY

(NOT

INCLUDED

IN KIT)

WASHER

SCREW

PURGE VALVE HOUSING MAINTENANCE KIT

FIGURE 7 - MAINTENANCE KIT CONTENTS (ILLUSTRA TIONS A THROUGH E)

PISTON

ASSEMBLY

RETURN

SPRING

PURGE

VALVE

EXHAUST

GUIDE

SHOULDER

BOLT

HORIZONTAL

DELIVERY CHECK

VALVE HOUSING

(NOT INCLUDED

IN KIT)

RETAINER

DELIVERY CHECK VALVE KIT

VERTICAL

O-RING

CHECK VALVE

SPRING

Page 10

EXHAUST

COVER

SCREWS

ADAPTER

SILENCER

GASKET

EXHAUST COVER

KIT

GASKET

ADAPTER

EXHAUST

COVER SCREWS

SILENCER KIT

ADAPTER

SCREWS

SILENCER

BODY

FILTER SILENCER

COVER

EXHAUST

COVER

DESICCANT

CARTRIDGE

DESICCANT

CARTRIDGE

O-RING OUTER

HOUSING

O-RING

SMALL

O-RING

LARGE

O-RING

STANDARD PURGE VALVE

DISCHARGE

LINE

UNLOADER

PURGE VALVE

ASSEMBLY

MEDIUM

O-RING

STANDARD

PURGE VALVE

ASSEMBLY

WASHER

SCREWS

SMALL

O-RING

LARGE

O-RING

ADAPTER

CHECK

VALVE

DESICCANT CARTRIDGE KIT

CHECK VALVE

MAKEUP AIR LINE

LETTER "U" STAMPED HERE

TO IDENTIFY DLU ASSEMBLY

DISCHARGE LINE UNLOADER PURGE VALVE

FIGURE 8 - MAINTENANCE KIT CONTENTS (ILLUSTRA TIONS F THROUGH J)

MAKEUP LINE KIT

ADAPTER

Page 11

SMALL

O-RING

DESICCANT

CARTRIDGE O-RING

OUTER HOUSING

O-RING

END COVER

END COVER REPLACEMENT KIT

MEDIUM

O-RING

LARGE O-RING

UNINSULATED

BUTT SPLICE CONNECTOR

SCREW

SEALING

RING

HEATER & THERMOSTAT KIT

WIRE HARNESS

ASSEMBLY

EYELET

W/HEAT SHRINK

INSULATOR

HEATER &

THERMOSTAT

ADHESIVE LINED

HEAT SHRINK TUBING

HEATER ELECTRICAL SPLICING KIT

UNIVERSAL

MOUNTING PLATE

FIGURE 9 - MAINTENANCE KIT CONTENTS (ILLUSTRA TIONS K THROUGH M)

DISASSEMBLY

The following disassembly procedure is presented for reference purposes and presupposes that a major rebuild of the Bendix® AD-9® or AD-9® IPC air dryer is being undertaken. Several replacement parts and maintenance kits are available which do not require full disassembly . The instructions provided with these parts and kits should be followed in lieu of the instructions presented here. Refer to Figures 7, 8 and 9 during disassembly.

Caution: While performing service on the AD-9® and AD-9® IPC air dryers, it is not recommended that a clamping device (vise, C-clamp, etc.) be used to hold any die cast aluminum component, as damage may result. To hold the end cover, install a pipe nipple in

Delivery Check Valve Removal

The current style AD-9 ® air dryer end cover has a horizontal delivery check valve while earlier styles contained a vertical design. Identify the style of AD-9® air dryer end cover and

proceed to the appropriate step for removal. See Figure 7, illustration E.

1. Vertical Delivery Check Valve Removal – Using an adjustable wrench or a 1-3/4" socket, remove the delivery check valve assembly and o-ring. Remove the o-ring from the check valve assembly.

Horizontal Delivery Check Valve Removal – Remove

the delivery check valve plug from the air dryer end cover.

2. Remove the spring, check valve body, and o-ring.

the supply port and clamp the nipple into a vise.

Page 12

Silencer Removal

If the air dryer purge valve has a silencer attached to it, identify the style of silencer before attempting to remove it. There are two different styles of silencers that have been used with the Bendix® AD-9® air dryer. One design is secured to the air dryer purge valve adapter with four cap screws that are visible from the bottom. The other is a snap-on design. See Figure 8, illustration G.

Screw Mounted Silencer

1. Remove the four screws that secure the exhaust cover, silencer cover, ﬁ lter and silencer body to the adapter.

2. Remove the three screws that secure the adapter to the purge valve. Remove the adapter and gasket.

Snap-on Silencer

1. Firmly grip the silencer and pull it away from the air dryer end cover.

2. Slide the adapter off of the exhaust cover.

3. Remove the three screws that secure the exhaust cover to the purge valve housing assembly of the end cover. Remove the exhaust cover and gasket.

Purge Valve Removal

1. Remove the three 1/4" screws that secure the purge valve housing assembly to the end cover assembly . Pull the purge valve housing assembly out of the end cover assembly . Remove the three o-rings from the exterior of the purge valve housing assembly. (The medium

o-ring is not included in DLU models.) The o-rings may be lodged in the end cover bores, if so, they must be removed. Refer to Figure 8, illustration J.

2. Purge Valve Disassembly: Note: In some cases a ﬂ at (non-extended) exhaust

cover is used. If an extended type exhaust cover is in use, (to accommodate the attachment of an exhaust hose), the exhaust cover must be carefully peeled off of the purge valve housing. Use a thin ﬂ at blade to pry

the exhaust cover off, taking care not to damage the potting material (RTV sealant) under the cover.

Removal of the piston from the purge valve housing

assembly requires a tool to hold the head of the purge piston while unscrewing the purge valve shoulder bolt. Remove the piston from the purge valve housing assembly using a twelve point 1/4" socket to hold the head of the purge valve shoulder bolt. See Figure 7,

illustration D.

A. Secure the top of the purge piston assembly using

the two opposing cast indentations and a removal tool. Remove the purge valve shoulder bolt from the bottom of the purge valve housing assembly. Remove the exhaust guide and purge valve from the purge valve housing.

B. Remove the purge piston assembly and return

spring from the opposite end of the purge valve housing assembly . Remove the quad ring from the purge piston assembly.

SMALL

O-RING

MEDIUM

O-RING

LARGE

O-RING

PURGE VALVE

ASSEMBLY

HEATER

ELEMENT

SCREW

SEALING

THERMOSTAT

RING

HEATER &

W/HEATER & THERMOSTAT INSTALLED

(SECTIONAL VIEW FROM BOTTOM)

HEATER &

SEALING RING

RUBBER CUSHION

THERMOSTAT

PURGE VALVE

HEATER &

THERMOSTAT

Step A

HEATER

ELEMENT

PURGE

VALVE

ASSEMBLY

PURGE VALVE HOUSING W/HEATER & THERMOSTAT

(SECTIONAL VIEW FROM BOTTOM)

Step B

SEALING RING

RUBBER CUSHION

THERMOSTAT

SEALING RING

FIGURE 10 - HEATER & THERMOSTAT REMOVAL & INSTALLATION

Page 13

SPECIAL ASSEMBLY,

MUST BE REPLACED BY

AD-9 SOFT SEAT

SPECIAL ASSEMBLY,

MUST BE REPLACED BY

AD-9 SOFT SEAT

AIR DRYER ASSY.

MAKEUP AIR LINE

(WITH 90° FITTING)

FIGURE 11 - BENDIX® AD-9® DROP IN AIR DRYER

AIR DRYER ASSY.

DELIVERY PORT

ADAPTER

DELIVERY PORT

ADAPTER

(WITH 90° FITTING)

Heater and Thermostat Assembly Removal

1. Remove the two screws that secure the heater and thermostat assembly to the purge valve assembly . See Figure 9, illustration L for kit contents.

CAUTION DO NOT PULL THE HEATER & THERMOSTAT ASSEMBLY STRAIGHT OUT OF THE PURGE VALVE BODY! READ STEP 2 COMPLETELY BEFORE A TTEMPTING REMOVAL.

2. Study Figure 10 closely and note the "Y" shape of the Heater & Thermostat assembly in its installed position in the purge valve housing. As illustrated, remove the heater & thermostat assembly by gently "rotating" the connector to the left (Step A) until the thermostat clears the purge valve housing, then slide the heater element out, to the right and up (Step B).

End Cover Removal

1. Remove the remaining six 3/8" cap screws, locknuts and twelve special washers that secure the end cover to the housing air dryer housing. Separate the end cover and desiccant cartridge from the housing. See Figure 9, illustration K.

2. Remove the end cover to outer housing o-ring.

3. Do not remove the safety valve from the end cover unless it has been proven defective. If replacement is required, apply thread sealant or Teflon® tape on the threads of the replacement valve and torque to 120–400 in. lbs. See Figure 1 for safety valve location.

CHECK VALVE

(WITH 90° FITTING)

MAKEUP AIR LINE

4. Place a strap or chain wrench around the desiccant cartridge so that it is approximately 2–3 inches away from the end cover. Rotate the cartridge counterclockwise until it completely separates from the end cover.

Note: A substantial torque (up to 50 lb. ft.) may be

required to perform this disassembly.

5. Remove the desiccant cartridge o-ring from the end cover.

Drop In Air Dryer Makeup Line Removal

1. Before beginning, note the approximate angle of

the fittings, check valve and the general routing of the makeup line on the air dryer. It is important that the same approximate routing be duplicated during re-installation. See Figure 11.

2. Disconnect the makeup line from the 90 degree ﬁ tting

on the check valve.

3. Disconnect the makeup line from the 90 degree ﬁ tting

on the port adapter itself or the check valve. Remove the adapter along with the attached 90 degree ﬁ tting.

CLEANING & INSPECTION

1. Using mineral spirits or an equivalent solvent, clean and thoroughly dry all metal parts.

2. Inspect the interior and exterior of all metal parts that will be reused for severe corrosion, pitting and cracks. Superficial corrosion and/or pitting on the exterior portion of the upper and lower body halves is acceptable.

3. Inspect the bores of both the end cover and the purge valve housing for deep scufﬁ ng or gouges.

Page 14

4. Make certain that all purge valve housing and end cover passages are open and free of obstructions.

5. Inspect the pipe threads in the end cover. Make certain they are clean and free of thread sealant.

6. Inspect the purge valve housing bore and seats for excessive wear and scufﬁ ng.

7. Inspect the purge valve piston seat for excessive wear.

8. Inspect all air line ﬁ ttings for corrosion. Clean all old thread sealant from the pipe threads.

9. All o-rings removed should be discarded and replaced with new o-rings provided in appropriate kit(s).

Any component exhibiting a condition described in step 1 to 8 should be replaced.

ASSEMBLY

The following assembly procedure is presented for reference purposes and presupposes that a major rebuild of the Bendix® AD-9® or AD-9® IPC air dryer is being undertaken. Several replacement parts and maintenance kits are available which do not require full disassembly . The instructions provided with these parts and kits should be followed in lieu of the instructions presented here. Refer to Figures 7, 8 and 9 during assembly.

Purge Valve Housing Assembly

1. Prior to assembly , coat all o-rings, o-ring grooves, and bores with a generous amount of the lubricant included in the maintenance kit. See Figure 7, illustration D.

A. Install the quad-ring in its groove on the O.D. of the

purge piston. Place the return spring in the bore of the purge valve housing. Insert the purge piston into the I.D. of the return spring. Place the purge valve guide onto the shoulder bolt followed by the purge valve. Using a ratchet or wrench, screw the purge valve, purge valve guide and shoulder bolt into the purge housing until it bottoms. This will require a tool to hold the top of the purge piston from rotating as the shoulder bolt is screwed into the bottom of the purge piston to complete the purge valve assembly . Torque the shoulder bolt to 60–90 in. lbs.

B. Install the o-rings on the purge valve housing, placing

each in its appropriate location. Note the medium o-ring is not used on Discharge Line Unloaded (DLU) models. If the exhaust cover was removed during disassembly, install it on the purge valve assembly making certain the “bubble” portion is positioned over the thermostat. Install the assembled purge valve housing in the end cover. Make certain to orient both parts such that the connector is approximately 10 degrees clockwise from the supply port, while making certain the purge valve housing is fully seated against the end cover. Secure the purge valve housing to the end cover using the three 1/4"

DELIVERY CHECK

VALVE BODY

7/16" DEEP

SOCKET WITH A

3/8" DRIVE

BENCH VISE

FIGURE 12 - VERTICAL DELIVERY CHECK VALVE

APPLY LUBRICANT

CHECK

VALVE

SPRING

RETAINER

self-tapping screws. Start all three screws by hand then torque to 50–80 in. lbs.

Delivery Check Valve Assembly

The current style AD-9® air dryer end cover has a

horizontal delivery check valve while earlier styles contained a vertical design. Identify the style of AD-9® air dryer end cover and proceed to the appropriate step

for installation. See Figure 7, illustration E.

Vertical Delivery Check Valve –

1. Assemble the spring to the retainer and check valve. Ensure the spring is fully seated on the retainer and the check valve.

2. Lubricate the entire spherical surface of the check valve

and bore chamfer of the check valve housing with the lubricant provided in the kit.

3. Place the retainer, spring and check valve sub-

assembly into the check valve housing. Press the retainer using a 7/16" deep socket with a 3/8" drive, and a vise as shown in Figure 12.

4. Inspect the bore of the end cover. Make certain that the

end cover passage is open and free of obstructions.

5. Install the o-ring on the outer body of the delivery check

valve assembly. Ensure the o-ring is seated properly and not twisted. Lubricate the o-ring.

6. Install the delivery check valve assembly into the end

cover. Torque to 200–250 in. lbs.

Horizontal Delivery Check Valve –

1. Lubricate the o-ring and the long check valve body with

the lubricant provided. Use only the lubricant contained in the kit.

2. Install the o-ring on the long check valve body. Push

the o-ring down, over the 3 guide lands until it is in the o-ring groove. Ensure the o-ring is seated properly and not twisted.

3. Install the spring on the white check valve body so that

the small coils of the spring slip over the check valve body.

Page 15

1&9

FIGURE 13 - END COVER TO HOUSING TORQUE PA TTERN

4. Install the assembled long check valve body, o-ring, and spring in the end cover delivery check valve port so that the o-ring rests on its seat in the end cover and the spring is visible.

5. Install the delivery check valve plug that was removed during the disassembly, into the air dryer end cover. See Figure 5. T orque the plug to 130–170 inch pounds.

Drop In Air Dryer Makeup Line Assembly

1. Install the adapter and the attached 90 degree ﬁ tting in

the air dryer. Take care that the replacement adapter and attached ﬁ tting is in the same approximate position as the original. See Figure 11.

2. Install the check valve and ﬁ tting, taking care that the replacement is in the same approximate position as the original.

3. Install the makeup line and tighten the tubing nuts at both ends while preventing the 90 degree ﬁ ttings from turning. Tighten the nuts sufﬁ ciently to prevent air leakage, but do not over tighten.

Air Dryer Assembly

1. Install the desiccant cartridge o-ring in its groove in the end cover. Using a light coat of lubricant (included in kit), lubricate the bottom of the desiccant cartridge in the area that will contact the o-ring and end cover. Screw the desiccant cartridge into the end cover until contact is made between it and the o-ring. Using a strap or chain wrench positioned 2–3 inches from the bottom of the cartridge, turn the desiccant cartridge clockwise 180–225 degrees beyond the position where initial contact was made between the cartridge and end cover o-ring. Torque should not exceed 50 ft. lbs.

2. Install the end cover outer housing o-ring on the

shoulder in the end cover. Place the housing over the desiccant cartridge and align the holes. Install the six 3/8" cap screws, locknuts and twelve special washers, making certain they are in the proper position as marked during disassembly . The two longer 3/8" cap screws will be used to secure the air dryer to its mounting bracket. Tighten the six cap screws and nuts in a star pattern in a fashion similar to Figure 13; depending on lower bracket location. Torque to 270–385 in. lbs.

Note: The two remaining bolt holes in the end cover and

two 3/8" cap screws must be the ones marked during disassembly to assure proper orientation of the ports and adequate length of the cap screws.

INSTALLATION

LOWER

BRACKET



2-1/8"

END

COVER

FIGURE 14 - LOWER BRACKET INSTALLATION

EXTRA

LONG

BRACKET

CAP SCREW



SPECIAL WASHER

1. Install the assembled Bendix® AD-9® or AD-9® IPC air

dryer back onto the vehicle by slipping it into the upper mounting bracket. Align the two unused holes in the end cover with the bottom mounting bracket such that the bottom bracket supports the air dryer. The air dryer end cover should rest on the bracket. Using the remaining two 3/8" cap screws, four special washers, and two locknuts, secure the air dryer to the lower bracket. Tighten, then torque the two remaining cap screws to 270–385 in. lbs. See Figure 14.

2. See Figure 7, illustrations A and B, to determine the

mounting bracket type.

Illustration A Style - Attach the mounting strap to the

air dryer and secure it to the mounting saddle with the 5 /16" X 4-1/2" hex cap screw and nut. Torque to 80–120 in. lbs.

Illustration B Style - Place the isolator between the

upper bracket and air dryer. Secure the air dryer to the upper bracket with the mounting strap. Tighten the adjusting nut to 50–60 in. lbs.

Page 16

3. Reconnect the three air lines to the proper ports on the end cover (identiﬁ ed during disassembly).

4. Reconnect the vehicle wiring harness to the air dryer heater and thermostat assembly connector by plugging it into the air dryer connector until its lock tab snaps in place.

5. Before placing vehicle back into service, perform the Operation and Leakage Tests stated earlier in this

manual.

RETROFITTING THE BENDIX® AD-9® AIR DRYER

GENERAL

The following retrofit instructions are presented for reference purposes only since Bendix aftermarket retroﬁ t and replacement air dryers are packaged with the most upto-date installation instructions. The instructions packaged

with the Bendix® AD-9® and AD-9® IPC air dryers should be followed in lieu of those presented here.

The preceding portion of this manual deals with “in-service” repair and/or replacement of the AD-9® and AD-9® IPC air dryers. The portion of the manual that follows is concerned with installing an AD-9® or AD-9® IPC air dryer on a vehicle not previously equipped with one.

VEHICLE APPLICA TION REQUIREMENTS

The basic application requirements presented here apply to a standard air dryer installation. The majority of highway vehicles in use today will meet these basic requirements

however, some may not. Examples of vehicles that may not meet the requirements include, bulk trailer unloading operations and other high air consumption/continuous ﬂ ow systems. While the AD-9 used on these vehicles, the standard installation procedure presented in this manual may require modiﬁ cation to assure proper operation and service life. Consult your local authorized Bendix parts outlet or sales representative for additional information.

1. Charge Cycle Time - The Bendix® AD-9® and AD-9® IPC air dryers are designed to provide clean, dry air for the brake system. When a vehicle’s air system is used to operate non-brake air accessories, it is necessary to determine that during normal, daily operation the compressor should recover from governor “cut-in” to governor “cut-out” (usually 100 psi to 120 psi) in 90 seconds or less at engine RPMs commensurate with the vehicle vocation. If the recovery time consistently exceeds this limit, it may be necessary to “bypass” the air accessory responsible for the high air usage. Consult your local authorized Bendix parts outlet or sales representative for additional information.

or AD-9® IPC air dryer can be

COMPRESSOR

10 AMP - 12V

5 AMP - 24V

FUSE

UNLOADER

PORT

CON

SUP

14 GA WIRE

TO IGNITION

& GROUND

DEL

GOVERNOR

SAFETY VALVE

CONTROL

(HIDDEN)

SUPPLY

DELIVERY

RESERVOIR

TO RESERVOIR

FIGURE 11 - AD-9® AIR DRYER CHARGE CYCLE

Page 17

2. Purge Cycle Time - During normal vehicle operation, the air compressor must remain unloaded for a

minimum of 20 seconds for the standard air dryer or 30 seconds for the extended purge model. These

minimum purge times are required to ensure complete regeneration of the desiccant material. If the purge time is occasionally shorter than the times speciﬁ ed, no permanent ill effect should be expected; however , if the purge time is consistently less than the minimum, an accessory by-pass system must be installed.

3. European Air Brake Systems - Brake systems that incorporate compressors without integral unloading

mechanisms, and/or utilize a compressor discharge

line unloader valve, have special Bendix

AD-9® and

AD-9® IPC air dryer installation requirements. Consult your local authorized Bendix parts outlet or sales representative for additional information.

4. Holset “E or QE” Type Air Compressors - In order for the AD-9 or AD-9 IPC air dryer to function properly when installed with the Holset Type “E or QE” compressor, several specialized Holset components are required. Consult your local authorized Holset parts outlet or sales representative for additional information.

5. Use of Standard or Extended Purge AD-9 or AD-9 IPC Air Dryer - Use the following guidelines:

Total Vehicle

Reservoir Volume

Bendix® AD-9® or

AD-9® IPC Air Dryer

Requirement

Less than 9,000 cu. in. Standard Air Dryer

9,000 - 12,500 cu. in. Extended Purge Air Dryer

Greater than 12,500 cu. in. Contact Bendix Rep. or Bendix

Engineering

VEHICLE PREPARATION

1. Park the vehicle on a level surface and prevent movement by means other than the brakes.

2. Drain all reservoirs to 0 psi (0 kPa).

LOCATING THE BENDIX® AD-9® AIR DRYER ON VEHICLE

1. The AD-9 or AD-9 IPC air dryer must be mounted vertically (purge exhaust toward road surface) outside the engine compartment in an area of air ﬂ ow while the vehicle is in motion. The air dryer must not be exposed to direct wheel splash (located behind axle mud ﬂ ap is acceptable).

2. Locate the AD-9 or AD-9 IPC air dryer as close to the ﬁ rst (supply) reservoir as possible.

3. Do not locate the AD-9 or AD-9

IPC air dryer near heat producing components, such as the vehicle exhaust, and make certain adequate clearance from moving components (e.g. drive shaft, suspension, pitman arm, etc.) is provided.

4. Locate the AD-9 or AD-9 IPC air dryer on the vehicle so that a minimum of 11 inches (28 cm) clearance below the end cover is available to allow servicing. Alternatively, provide access to the bracket bolts so the unit may be removed for servicing.

5. When choosing the mounting location for the AD-9 or AD-9

IPC air dryer, note the discharge line length requirements stated under the heading Connecting the Air Lines, elsewhere in this instruction sheet.

Important Note: Under normal operating conditions,

the maximum inlet air temperature for the AD-9 and AD-9 IPC air dryers is 160 degrees Fahrenheit.

MOUNTING THE BENDIX® AD-9® AND AD-9® IPC AIR DRYER

1. To install the lower mounting bracket on the AD-9 or AD-9 IPC air dryer, it will be necessary to remove and discard two of the end cover bolts and locknuts. To determine which end cover bolts to utilize to attach the lower bracket, take into consideration the piping connections required to install the air dryer and use those that will best position the unit for ease of installation. Locate the bracket such that it cradles the end cover as shown in Figure 9. Utilizing the two 2-3/8" long cap screws, locknuts and special washers provided with the AD-9 or AD-9 IPC air dryer retroﬁ t unit, attach the lower mounting bracket and torque to 270–385 in. lbs.

2. Assemble the mounting strap and upper mounting bracket as illustrated in Figure 10, by utilizing the 5/16" cap screw and sleeve nut.

3. Place the upper bracket assembly onto the shell of the AD-9 or AD-9 IPC air dryer and orient it so that it bears entirely on the cylindrical surface and does not extend onto the domed top. The slot spacing between the upper and lower bracket should be a minimum of

5.5 inches apart. Do not tighten strap onto the shell at this time.

4. Mount the air dryer on the vehicle using 3/8" bolts (grade 5 min.) and washers. Torque to 25 ft. lbs. (300 inch pounds.) After positioning and mounting the upper bracket assembly according to the installation requirements, torque the 5/16" nut to 80–120 in. lbs. to tighten strap onto the shell.

Page 18

CONNECTING THE AIR LINES

PURGE CONTROL LINE

1. Install a purge control air line having a minimum inside diameter of 3/16 inches between the Bendix® AD-9® or AD-9 unused unloader port on the governor. The control line must be plumbed direct to the governor and not in series with automatic drain valves, lubrication systems, etc.

2. The control line should slope downward to the end cover without forming potential water traps.

DISCHARGE LINE

General:

Refer to Appendix A, Table A for recommended discharge line lengths and sizes for various vehicle applications and vocations.

PURGE EXHAUST LINE

1. If it is necessary to direct AD-9 or AD-9 IPC air dryer discharge contaminants away from vehicle components it may be necessary to purchase a special exhaust cover for the AD-9 or AD-9 IPC air dryer (Pc. No.

5003838). A one inch (25.4 mm) I.D. hose can be clamped on the special air dryer exhaust cover.

WIRING THE HEATER/THERMOSTAT

1. Determine the vehicle’s electrical system voltage and make certain that the AD-9 or AD-9 IPC air dryer that is to be installed contains the same voltage heater. Use the AD-9 or AD-9 IPC air dryer part number to conﬁ rm the proper voltage. The AD-9 and AD-9 IPC air dryers are available with either a 12 or 24 volt heater which uses 75 watts of power.

2. A two lead, 12 inch, wire harness with attached weather resistant connector is supplied with all retroﬁ t and replacement AD-9 and or AD-9 IPC air dryers. Connect one of the two leads of the wire harness to the engine kill or ignition switch. The remaining lead of the wire harness must be connected to a good vehicle ground (not to the air dryer or its mounting bracket). A fuse should be installed in the power carrying wire; install a 10 amp fuse for 12 volt heaters and a 5 amp fuse for a 24 volt heater.

IPC air dryer end cover control port and an

3. Use 14 GA wire if it is necessary to lengthen the wire harness provided with the AD-9

or AD-9 IPC air dryer.

Make certain all wire splices are waterproofed.

4. Tie wrap or support all electrical wire leading to the AD-9 or AD-9 IPC air dryer at 6–8 inch intervals. Note: Wires should have sufﬁ cient slack and not be completely taught.

TESTING THE BENDIX

AD-9® AND AD-9® IPC

AIR DRYER

Before placing the vehicle in service, perform the following tests:

1. Close all reservoir drain cocks.

2. Build up system pressure to governor cut-out and note that the air dryer purges with an audible escape of air.

3. “Fan” 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 a purge at the air dryer exhaust.

4. It is recommended that the following items be tested for leakage to assure that the AD-9 or AD-9 IPC air dryer will not cycle excessively.

(A) Total air system leakage (See Bendix® Air Brake

Handbook, BW5057). (B) Compressor unloader mechanism. (C) Governor. (D) Drain cock and safety valve in first (supply)

reservoir. (E) All air connections leading to and from the ﬁ rst

(supply) reservoir.

Page 19

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

1. Dryer is constantly “cycling” or purging. Dryer purges frequently (every 4 minutes or less while vehicle is idling).

A. Excessive system leakage.

IMPORTANT: Note whether air pressure loss is shown on dash gauge(s). Pressure loss shown on gauges is caused by service brake system or component leakage. Pressure loss NOT SHOWN on gauges is caused by supply system or component leakage.

A. If leakage IS SHOWN on gauges, test for excessive service

brake system leakage.

Allowable leakage:

Pre-121 vehicles, single vehicles - 2 psi / minute.

Tractor trailer - 3 psi / minute. 121 vehicles, single vehicle - 1 psi / minute per service reservoir. Tractor trailer - 3 psi / minute per service reservoir . Repair and

retest as required.

If leakage is NOT SHOWN on gauges test for excessive supply

system leakage.

Remove drain cock or valve in supply reservoir (wet tank) and

install air gauge. Build system pressure, allow air dryer to purge and observe air gauge in supply reservoir. Pressure drop should not exceed 1 psi per minute.

Perform tests 1 to 6 in the order presented.

Page 20

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

1. Dryer is constantly “cycling” or purging. Dryer purges frequently (every 4 minutes or less while vehicle is idling) (continued).

A. Excessive system leakage.

1. Test ﬁ ttings, hoses, lines and connections. Apply soap solution to detect excessive leakage. Tighten or replace as needed then repeat the air dryer charge-purge cycle and observe the gauge installed in the supply reservoir. If leakage is within limits, remove gauge from reservoir and replace drain cock or valve. If excessive leakage is detected, continue testing.

2. Test accessories connected to supply reservoir. Drain all air pressure from system, disconnect all air lines leading to accessories (fan clutch, wipers, air seats, etc.) and plug the reservoir at disconnection point. Build air system pressure until air dryer purges and observe supply reservoir gauge. If leakage is no longer excessive, repair or replace leaking accessory. If excessive leakage is detected, continue testing.

3. Test governor leakage. Build system pressure to governor cutout, turn off engine and apply soap solution to governor exhaust port and around cap. Leakage should not exceed a 1 in. bubble in 5 seconds. Reduce system pressure to 80 psi or less, and reapply soap solution. Leakage should not exceed a 1 in. bubble in 5 seconds. If excessive leakage is detected in either test, repair or replace governor.

4. Test compressor unloader leakage. Drain all air pressure from system and remove the governor from the compressor. Temporarily plug the governor unloader port or air line that mated with, or connected to, the compressor. Build air system pressure until air dryer purges then IMMEDIATELY SHUT OFF THE ENGINE. Observe the air gauge in the supply reservoir. If leakage is within limits, replace the compressor unloaders. Reconnect the governor to the compressor (after removing plug installed in governor) and retest while observing supply reservoir gauge. If excessive leakage is detected, continue testing.

5. Test air dryer purge valve and outlet (delivery) check valve. Drain all air pressure from system, remove the control line connection at the air dryer and plug the end of the air line leading to the governor (not the air dryer control port). Build system pressure to governor cut-out and observe air gauge. If little or no pressure drop is observed replace the air dryer check valve. If pressure drop continues, apply soap solution to air dryer purge exhaust and purge control port (where the control line was removed). Leakage should not exceed a 1 in. bubble in 5 seconds. If leakage is excessive, repair or replace purge valve assembly.

Page 21

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

1. Dryer is constantly “cycling” or purging. Dryer purges frequently (every 4 minutes or less while vehicle is idling) (continued).

A. Excessive system leakage.

6. With gauge installed at RES port of governor, pressure should not drop below ”Cut-In” pressure at the onset of the compressor “Unloaded” cycle. If pressure drops, check for “kinks” or restrictions in line connected to RES port. Line connected to RES port on governor must be same diameter, or preferably larger than, lines connected to UNL port(s) on governor.

B. Leaking purge valve housing

assembly and/or o-rings in air dryer end cover.

C. Holset

“E” type compressor. C. Test the Holset® E Compressor unloader system with feedback

B. With the supply port open to atmosphere, apply 120 psi at the

control port. Apply a soap solution to the supply port and exhaust port (purge valve seat area). Permissible leakage - 1" bubble in 5 seconds.

line and check valve for proper operation. Make certain Holset ECON is not in use with the drop-in version of the air dryer, if so, remove and retest.

When installing a Bendix Drop-In air dryer in a system equipped with a Holset E or QE compressor, remove the Holset ECON valve along with its feedback and governor control line.

Check Valve

Feedback Line

Typical Drop-In Air Dryer End Cover

Page 22

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

2. Water and/or Oil in Supply or Service Reservoir.

A. Desiccant requires replacement

- excessive contaminants in desiccant cartridge assembly.

A. Replace desiccant cartridge.

B. Improper discharge line length or

improper line material. Maximum air dryer inlet temperature is exceeded.

C. Air system charged from outside

air source (outside air not passing through air dryer)

D. Air dryer not purging (see

Symptom #5).

E. Purge (air exhaust) time insufﬁ cient

due to excessive system leakage (see causes for Symptom #1).

F. Excessive air usage, duty cycle

too high - Air dryer not compatible with vehicle air system requirement (Improper air dryer/vehicle application).

NOTE: Duty Cycle is the ratio of time the compressor spends building air to total engine running time. Air compressors are designed to build air (run “loaded”) up to 25% of the time. Higher duty cycles cause conditions that affect air brake charging system performance which may require additional maintenance. Factors that add to the duty cycle are: air suspension, additional air accessories, use of an undersized compressor, frequent stops, excessive leakage from ﬁ ttings, connections, lines, chambers or valves, etc.

B. Refer to section entitled Connecting the Air Lines as well as

Appendix A, Table A columns 1 & 2 then check line size and length.

C. If system must have outside air ﬁ ll provision, outside air should

pass through the air dryer. This practice should be minimized.

D. See Symptom #5.

E. Check causes and remedies for Symptom #1.

F. See Appendix A, Table A, column 1, for recommended

compressor sizes. If the compressor is “too small” for the vehicle vocation (for example, where a vehicle’s vocation has changed or service conditions exceed the original vehicle or engine OE spec’s) then upgrade the compressor. Note: The costs incurred (e.g. installing a larger capacity compressor, etc.) are not covered under original compressor warranty.

Charge Cycle T ime - Bendix® AD-9® and AD-9® IPC air dryers

are designed to provide clean, dry air for the brake system. When a vehicle’s air system is used to operate non-brake air accessories it is necessary to determine that; during normal, daily operation the compressor should recover from governor “cut-in” to governor “cut-out” (usually 100 psi to 120 psi) in 90 seconds or less at engine RPM’s commensurate with the vehicle vocation. If the recovery time consistently exceeds this limit, it may be necessary to “bypass” the air accessory responsible for the high air usage. An example of where a by-pass system would be required is when the compressor is used to pressurize a tank trailer for purposes of off-loading product. Consult your local authorized Bendix parts outlet or sales representative for additional information.

Page 23

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

2. Water and/or Oil in Supply or Service Reservoir (continued).

(Continued) Purge Cycle Time - During normal vehicle operation, the

air compressor must remain unloaded for a minimum of 20 seconds for the standard Bendix

AD-9® and AD-9® IPC air dryer or 30 seconds for the extended purge model. These minimum purge times are required to ensure complete regeneration of the desiccant material. If the purge time is consistently less than the minimum, an accessory by-pass system must be installed. Consult your local authorized Bendix parts outlet or sales representative for additional information.

European Air Brake Systems - Brake systems that incorporate

compressors without integral unloading mechanisms and/ or utilize a compressor discharge line unloader valve have special air dryer installation requirements. Consult your local authorized Bendix parts outlet or sales representative for additional information.

Air Compressor Size - Although the AD-9 and AD-9

IPC air dryers can be used in conjunction with larger compressors, it was designed primarily for units rated for up to 17 CFM. It is recommended that when using the AD-9 or AD-9 IPC air dryer with a compressor which has a rated displacement exceeding 17 CFM that an authorized Bendix parts outlet or Bendix marketing representative be contacted for assistance.

G. Air compressor discharge and/or

air dryer inlet temperature too high.

G. Restricted discharge line. See Appendix A, Table A, column 1

& 2 for recommended sizes. If discharge line is restricted or more than 1/16” carbon build up is found, replace the discharge line. Replace as necessary.

Discharge Line Freeze-Up. The discharge line must maintain a constant slope down from the compressor to the air dryer inlet ﬁ tting to avoid low points where ice may form and block the ﬂ ow. If, instead, ice blockages occur at the air dryer inlet, insulation may be added here, or if the inlet ﬁ tting is a typical 90 degree ﬁ tting, it may be changed to a straight or 45 degree ﬁ tting. For more information on how to help prevent discharge line freezeups, see Bendix Bulletins TCH-008-021 and TCH-008-022. Shorter discharge line lengths or insulation may be required in cold climates.

Insufﬁ cient coolant ﬂ ow through compressor. Inspect coolant line. Replace as necessary (I.D. is 1/2” min.). Inspect the coolant lines for kinks and restrictions and ﬁ ttings for restrictions. Replace as necessary. V erify coolant lines go from engine block to compressor and back to the water pump. Repair as necessary.

Restricted air inlet (not enough air to compressor). Check compressor air inlet line for restrictions, brittleness, soft or sagging hose conditions, etc. Repair as necessary. Inlet line size is 3/4 ID. Maximum restriction requirement for compressors is 25 inches of water. Check the engine air ﬁ lter and service if necessary (if possible, check the air ﬁ lter usage indicator).

Page 24

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

2. Water and/or Oil in Supply or Service Reservoir (continued).

(Continued) Poorly ﬁ ltered inlet air (poor air quality to compressor). Check

for leaking, damaged or malfunctioning compressor air inlet components (e.g. induction line, ﬁ ttings, gaskets, ﬁ lter bodies, etc.). Repair inlet components as needed. Note: Dirt ingestion will damage compressor and is not covered under warranty.

If you found excessive oil present in the service reservoir and you did not ﬁ nd any issues above, the compressor may be passing oil.

Replace compressor. If still under warranty , follow normal warranty process.

H. Compressor malfunction. H. If excessive oil is present in the service reservoir and no other

issues (from above) were found, the compressor may be passing oil. Test the compressor using the Bendix cup method as described in the Bendix compressor service manual and referred to in Appendix A, Table A, column 5.

Replace compressor. If still under warranty , follow normal warranty process.

I. Air by-passes desiccant cartridge

assembly.

I. If the vehicle uses a Holset® compressor, inspect the

feedback check valve for proper installation and operation.

When replacing the desiccant cartridge, make sure desiccant cartridge assembly is properly installed and sealing rings are in place on mounting surface of desiccant cartridge.

Check Valve

BASIC™

3. Oil present at air dryer purge exhaust or cartridge during maintenance.

Feed Back Line

Typical Drop-In Air Dryer End Cover

J. Desiccant requires replacement. J. Replace desiccant cartridge assembly. Refer to Appendix A,

Table A columns 3 & 4 for recommended intervals.

A. Air brake charging system is

functioning normally.

A. Air dryers remove water and oil from the air brake charging

system. A small amount of oil is normal. Check that regular maintenance is being performed and that the amount of oil in the air tanks (reservoirs) is within the acceptable range shown on the BASIC cup (see also column 5 of Appendix A, Table A). Replace the air dryer cartridge as needed and return the vehicle to service.

Page 25

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

4. Safety valve on air dryer “popping off” or exhausting air.

A. Restriction between air dryer and

supply (ﬁ rst) reservoir.

B. Air dryer safety valve malfunction. B. Verify relief pressure is at vehicle or component manufacturer

C. Desiccant cartridge maintenance

required.

D. Malfunctioning discharge check

valve in end cover of the Benidix AD-IP® air dryer.

E. Excessive pressure pulsations

from compressor. (Typical single cylinder type).

F. Governor malfunction. Missing

or restricted governor control line installation.

A. Check to determine if air is reaching supply reservoir. Inspect

for kinked tubing or hose. Check for undrilled or restricted hose or tubing ﬁ ttings and repair or replace as needed.

speciﬁ cations. Replace if malfunctioning.

C. Refer to Appendix A ,Table A and column 3. Check compressor

for excessive oil passing and/or correct compressor installation. Repair or replace as necessary. Replace desiccant cartridge.

D. Test to determine if air is passing through check valve. Repair

or replace.

E. Increase volume in discharge line by increasing length or

diameter. Add a ping tank (small reservoir).

F . Test governor operation and/or inspect the control line leading

from the governor UNL (unloader) port to the air dryer control port.

5. Constant exhaust of air at air dryer purge valve exhaust. (Charge mode.)

6. Can not build system air pressure.

A. Air dryer purge valve leaking

excessively.

B. Compressor fails to unload (stop

compressing air) and air dryer purge exhaust makes “sputtering” or “popping” sound.

C. Purge control line connected

to reservoir or exhaust port of governor.

D. Purge valve frozen open -

malfunctioning heater and

thermostat, wiring, blown fuse. E. Excessive system leakage. E. See Symptom #1. F. Purge valve stays open - supply air

leaks to control side. A. Inlet and outlet air connections

reversed. B. Check valve between air dryer and

ﬁ rst reservoir. C. Kinked or blocked (plugged)

discharge line. D. Excessive bends in discharge line

(water collects and freezes) E. Refer to Symptom 4, Causes E & F.E. Refer to Symptom #4, Remedies E & F.

A. With compressor loaded, apply soap solution

on purge valve exhaust, to test for excessive leakage. Refer to Technical Bulletin TCH-008-040. Repair purge valve as necessary.

B. Conﬁ rm failure to unload by increasing & decreasing engine

RPM and noting change in the rate of leakage and intensity of accompanying leakage sound. Repair/replace compressor unloaders.

C. Purge control line must be connected to unloader port of

governor.

D. Test heater and thermostat as described in Preventive

Maintenance Section.

F. Repair purge valve and housing.

A. Connect compressor discharge to air dryer supply port.

Reconnect lines properly.

B. Test check valve for proper operation. Repair or replace as

necessary.

C. Check to determine if air passes through discharge line. Check

for kinks, bends, excessive carbon deposits, or ice blockage.

D. Discharge line should be constantly sloping from compressor

to air dryer with as few bends as possible.

Page 26

Bendix® AD-9® AND AD-9® IPC AIR DRYER TROUBLESHOOTING CHART

SYMPTOMS CAUSE REMEDY

7. Air dryer does not purge or exhaust air.

8. Desiccant material being expelled from air dryer purge valve exhaust (may look like whitish liquid or paste or small beads.)

- OR -

Unsatisfactory desiccant life.

9. “Pinging” noise excessive during compressor loaded cycle.

10. Constant seepage of air at air dryer purge valve exhaust (non-charging mode.)

11. The air dryer purge piston cycles rapidly in the compressor unloaded (noncompressing) mode.

A. Missing, broken, kinked, frozen,

plugged or disconnected purge control line.

B. Faulty air dryer purge valve. B. After determining air reaches purge valve (Remedy A above),

C. See Causes, B, E, G for Symptom

#4.

A. This symptom is almost always

accompanied by one or more of Symptoms 1, 2, 3, 4 and 5. See related causes for these symptoms above.

B. Air dryer not securely mounted.

(Excessive vibration.)

C. Malfunctioning or saturated

desiccant cartridge.

D. Compressor passing excessive oil. D. Check for proper compressor installation; if symptoms persist,

E. Desiccant cartridge not assembled

properly to end cover. (Loose attachment)

A. Defective check valve assembly in

air dryer end cover.

B. Leaking Turbo Cut-off valve. B. Repair or replace purge valve assembly. C. Leaking purge valve control piston

o-ring.

A. Defective check valve assembly in

air dryer end cover. B. Leaking Turbo Cut-off valve. B. Repair or replace purge valve assembly C. Leaking purge valve control piston

o-ring. A. Compressor fails to “unload”. A. Faulty governor installation; no air line from governor to

A. Inspect control line from governor UNL (unloader) port to control

port of air dryer. Test to determine if air ﬂ ows through purge control line when compressor unloaded. Check for undrilled ﬁ ttings. (See Symptom #4, Remedy C.)

repair purge valve.

C. Refer to Remedies B, E, G for Symptom #4.

A. See Causes and Remedies for Symptoms 1, 2, 3, 4 and 5.

B. Vibration should be held to minimum. Add bracket supports or

change air dryer mounting location if necessary.

C. Replace desiccant cartridge assembly.

replace compressor.

E. Check the torque on the desiccant cartridge

to end cover attachment. Refer to assembly section of this data sheet.

A. Refer to Remedy C, Symptom #1.

C. Repair or replace purge valve assembly.

A. Refer to Remedy C, Symptom #1.

C. Repair or replace purge valve assembly.

compressor or line is kinked or restricted. Install or repair air line.

Page 27

Table A: Maintenance Schedule and Usage Guidelines

Regularly scheduled maintenance is the single most important factor in maintaining the air brake charging system.

Column 1

Recom- Recom- Acceptable Typical Discharge mended mended Reservoir Compressors Line Air Dryer Reservoir Oil Contents No. of Spec'd Cartridge Drain at Regular

Vehicle Used for:

Axles Replacement

Low Air Use

Compressor with less than 15% duty cycle

e.g. Line haul single trailer

w/o air suspension, air over

hydraulic brakes.

Compressor with up to 25% duty cycle

e.g. Line haul single trailer

with air suspension,

High Air Use

Compressor with up to 25% duty cycle

school bus.

RV,

less

550 air compressor

Tu-Flo

air compressor

Bendix

BA-921

e.g. Double/triple trailer,

open highway coach, (most)

pick-up & delivery, yard or

terminal jockey, off-highway,

construction, loggers, concrete

mixer, dump truck, ﬁ re truck.

less

Bendix

750 air compressor

Column 2 Column 3 Column 4 Column 5

I.D.

1/2 in.

Length

6 ft.

Schedule2 Drain Interval

BASIC

For oil carry-over

suggested

control

upgrades:

5/8 in. 9 ft.

9 ft.1/2 in.

Every 3

Years

Recommended

Every

Month -

Max of

every 90

For oil carry-over

suggested

control

upgrades:

days

5/8 in. 12 ft.

1/2 in.

12 ft.

Every 2

For oil carry-over

suggested

control

upgrades:

5/8 in. 15 ft.

Years

BASIC™ test

Bendix®

™

test

acceptable

range:

3 oil units

per month.

See

appendix

For the

BASIC

Test Kit:

Order

Bendix

P/N

5013711

acceptable

range:

5 oil units

per month.

See

appendix

Compressor with up to 25% duty cycle

e.g. City transit bus, refuse,

bulk unloaders, low boys,

Tu-Flo

Bendix

air compressor

™

5/8 in.

Every

Month

12 ft.

urban region coach, central tire

inﬂ ation.

12 or

less

For oil carry-over

, or DuraFlo 596

BA-922

control

upgrades:

3/4 in. 15 ft.

suggested

Every

Year

Bendix

Footnotes:

1 With increased air demand the air dryer cartridge needs to be replaced more often. 2 Use the drain valves to slowly drain all reservoirs to zero psi. 3 Allow the oil/water mixture to fully settle before measuring oil quantity. 4 T o counter above normal temperatures at the air dryer inlet, (and resultant oil-vapor passing

upstream in the air system) replace the discharge line with one of a larger diameter and/ or longer length. This helps reduce the air's temperature. If sufﬁ cient cooling occurs, the oil-vapor condenses and can be removed by the air dryer. Discharge line upgrades are not covered under warranty. Note: T o help prevent discharge line freeze-ups, shorter discharge line lengths or insulation may be required in cold climates. (See Bendix Bulletins TCH-008-021 and TCH-008-022, included in Appendix B, for more information.)

5 For certain vehicles/applications, where turbo-charged inlet air is used, a smaller size

compressor may be permissible.

Note: Compressor and/or air dryer upgrades are recommended in cases where duty cycle is greater than the normal range (for the examples above).

For Bendix

Tu-Flo® 550 and 750 compressors, unloader service is recommended every 250,000 miles.

Page 28

Appendix B

Additional Troubleshooting Information

The troubleshooting procedure presented on the following pages has been excerpted from a troubleshooting card entitled: Troubleshooting Charging and Air Supply Systems. The complete card can be obtained from authorized Bendix parts outlets under literature number BW1779. It is presented here because of the air dryers connection to the supply air system and for convenience. The procedure is not all inclusive, but rather represents the most commonly encountered complaints.

CONVENTIONAL SUPPLY SYSTEM & INTEGRAL PURGE AIR DRYER

HOLSET TYPE "E & QE" COMPRESSOR WITH ECON VALVE

COMPRESSOR

TWO CYLINDER.

COMPRESSOR

HOLSET

“E OR QE”

HOLSET

ECON VALVE

AIR DRYER

GOVERNOR

SAFETY

VALVE

STANDARD SINGLE

CHECK VALVE

AIR

DRYER

SPECIAL

SINGLE CHECK

("CHOKE" IN INLET)

STANDARD SINGLE CHECK VALVE

(USED W/INTEGRAL PURGE AIR

DRYERS)

REAR

SUPPLY

FRONT

SAFETY

VALVE

REAR

SUPPLY

FRONT

STANDARD SINGLE

CHECK VALVE

LOW PRESSURE

INDICATOR

DASH

GAUGE

DASH

GAUGE

LOW PRESSURE INDICATOR

DRAIN COCK

HOLSET TYPE "E & QE" COMPRESSOR W/O ECON VALVE

HOLSET

“E OR QE”

COMPRESSOR

GOVERNOR

SPECIAL

SINGLE CHECK

("CHOKE" IN INLET)

AIR DRYER

SUPPLY

SINGLE CHECK -

PROTECTION VALVE

(USED W/SYSTEM

PURGE AIR DRYERS)

SAFETY

VALVE

LOW PRESSURE

INDICATOR

REAR

FRONT

SINGLE CHECK VALVE (USED

W/INTEGRAL PURGE AIR DRYERS)

DASH

GAUGE