BENDIX SD-08-2433 User's Manual
Contents
1. Bendix AD 9si and AD 9si PuraGuard Oil Coalescing Air Dryer DESICCANT CARTRIDGE PURAGUARD OIL COALESCING SHOWN Enhanced With PuraGuerd Filter Technology Bendix Bansx Commercial Vohicio S ystoms Al Rights Reserved PT 22 EXTENDED PURGE CON 2 4 PORT UNLOADER TO COMPRESSOR MOUNTING HOLES 3 PER SIDE HEATER THERMOSTAT DELIVERY CHECK VALVE COVER GOVERNOR SAFETY VALVE GOVERNOR CUT OUT re PRESSURE STAMPED OUT 21 ON COVER SUPPLY FROM PURGE DELIVERY PORTS 2 COMPRESSOR VALVE PURGE VALVE 3 GOVERNOR sd EXHAUST OUT 21 DELIVERY PORTS 2 BOTTOM VIEW FIGURE 1 BENDIX AD 9si AND AD 9si PURAGUARD OIL COALESCING AIR DRYER GENERAL SAFETY GUIDELINES A WARNING PLEASE READ AND FOLLOW THESE INSTRUCTIONS A 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 electrically2. AD 9si Air Dryer section that follows TESTING THE BENDIX AD 9si AIR DRYER Before placing the vehicle into service perform the following tests 1 Close all reservoir drain valves 2 Build up system pressure to governor cut out and note that the Bendix AD 9si air dryer purges with an audible burst of air followed immediately by approximately 40 seconds of air flowing out of the purge valve 10 Bendix AD 9si Maintenance Kits Kit Description Piece No K092011 5008414 Delivery Check Valve Replacement Kit Desiccant Cartridge Replacement Kit Standard Desiccant Cartridge Replacement Kit Bendix AD 9si PuraGuard air dryer can be used to replace the standard cartridge 5008414PG K092010 109578 109579 800155 K021189 109871N Governor Kit Heater amp Thermostat Replacement 12 volt Heater amp Thermostat Replacement 24 volt Safety Valve Replacement Silencer Kit not shown Wiring Harness amp Splice Kit not shown Extended Purge Kits not shown 93 in Reservoir w 3 8 16 U bolts 5012561N 93 in Reservoir w 1 2 13 U bolts 5005309N 288 in Reservoir w 3 8 16 U bolts 5008972 Purge Valve Assembly Service Kit Pc No K022105 Configuration Bendix AD 9si Air Dryer AD 9si Air Dryer Soft Seat Version AD 9si Air Dryer Discharge Line Unloader AD 9si Air Dryer AD 9si Air Dryer Soft Seat Version AD 9si Air Dryer Discharge Line Unloader Purge Valve Assembly for
3. CHECK VALVE FRONT RESERVOIR DELIVERY PORT FIGURE 2 BENDIX AD 9si AIR DRYER WITH GOVERNOR CHARGE CYCLE CHARGE CYCLE Refer to Figures 2 and 4 When the compressor is running loaded compressing air compressed air flows through the compressor discharge line to the inlet IN 1 port of the air dryer body The compressed air often includes contaminates such as oil oil vapor water and water vapor Traveling through the discharge line and into the air dryer the temperature of the compressed air falls causing some of the contaminants to condense and drop to the bottom of the air dryer and purge valve assembly These contaminants are ready to be expelled at the next purge cycle The air then flows through the inlet tube and into the desiccant cartridge where it flows through an oil separator or coalescing filter if equipped with a Bendix PuraGuard oil coalescing cartridge which removes water in liquid form as well as liquid oil and solid contaminants Air then flows into the desiccant drying bed and becomes progressively more dry as water vapor adheres to the desiccant material in a process known as adsorption Dry air exits the desiccant cartridge through the outlet tube then flows to the delivery check valve Some air exiting the desiccant cartridge is diverted through the orifice into the purge volume area The delivery check valve opens supplying air to the two delivery ports The purge reservoir fills
4. Check the governor at both cut in and cut out positions for proper pressures and excessive leakage at the exhaust seals 14 BENDIX AD 9si AIR DRYER TROUBLESHOOTING CHART SYMPTOM CAUSE REMEDY 5 Cannot build system air A Supply pressure to the air dryer is not A Ensure the supply pressure to the air dryer is greater than pressure sufficient 110 psi during the system charge B Kinked or blocked plugged discharge B exhaust air valve exhaust may look like B Excessive dryer vibration whitish liquid or paste or small beads Unsatisfactory desiccantlife A Excessive system leakage A Refer to Symptom 1 Remedy A B Wrong vehicle application for AD 9si B Refer to Symptom 2 Remedy C air dryer C Compressor passing excessive oil C Pinging noise excessive A Single cylinder compressor with high A during compressor loaded pulse cycles cycle The air dryer purge piston A Compressor fails to unload cycles rapidly in the compressor unloaded non compressing mode Air dryer does not purge or A Faulty air dryer purge valve A Check to determine if air passes through discharge line Check for kinks bends excessive carbon deposits or ice blockage water collects and freezes to air dryer with as few bends as possible After determining that air reaches the purge valve piston by installing a Tee fitting with a pre
5. addition air which was flowing through the desiccant cartridge changes direction and begins to flow from the purge volume toward the open purge valve Contaminants collected by the air dryer filters and desiccant are removed by air flowing from the purge volume through the desiccant drying bed to the open purge valve The initial purge and desiccant cartridge decompression lasts only a few seconds evidenced by an audible burst of air at the air dryer exhaust COMPRESSOR COALESCING FILTER CONTROL PORT TURBO CUT OFF VALVE OPEN SAFETY VALVE E DESICCANT BED PURGE ORIFICE PURGE AIR EXTENDED PURGE PORT REAR RESERVOIR DELIVERY CHECK FRONT RESERVOIR DELIVERY PORT FIGURE 4 BENDIX AD 9si AIR DRYER WITHOUT GOVERNOR CHARGE CYCLE The actual regeneration of the desiccant drying bed begins as dry air from the purge volume flows through the purge orifice into the desiccant bed Pressurized air from the purge volume expands after passing through the purge orifice its pressure lowers and its volume increases The flow of dry air through the drying bed regenerates the desiccant material by removing any water vapor adhering to it Approximately 40 seconds are required for the entire contents of the purge volume of a Bendix AD 9si air dryer to flow through the desiccant drying bed This time will increase if the dryer is fitted with an extended purge reservoir The delivery check valv
6. climate conditions above 40 C 40 F K031560 K031562 K031559 Arctic Purge Valve Assembly for climate conditions of 40 C to 50 C 40 F to 58 F K031561 K031563 3 Apply and release the service brakes several times 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 t is recommended that the total air system be tested for leakage to ensure that the AD 9si air dryer will not cycle excessively It is important to read and adhere to the following instruction to ensure the brake system operates safely after bypassing the air dryer TEMPORARY AIR DRYER BYPASS To temporarily bypass the air dryer follow these procedures and be sure to adhere to the General Safety Guidelines outlined elsewhere in this document Make sure that all residual pressure has been released Slowly loosen the fitting that connects the air compressor discharge line to the air dryer inlet port IN 1 thereby allowing any pressure trapped in the air dryer purge reservoir to escape to the atmosphere Once the pressure has escaped and air flow has ceased remove the fitting DESICCANT CARTRIDGE REPLACEMENT KIT HEATER amp THERMOSTAT REPLACEMENT KIT SAFETY HEATER amp HEATER THERMOSTAT VALVE SCREWS DELIVERY CHECK VALVE em a Vi re REPLACEMENT KIT b i FORL DELIVERY U gt LEA SMALL CHECK V
7. storing air that will be used to regenerate the desiccant during the purge cycle The air dryer will remain in the charge cycle until the air brake system pressure builds to the governor cut out setting of approximately 130 psi COMPRESSOR OIL CONTROL S LINE CONTROL PORT TURBO CUT OFF VALVE CLOSED EXHAUST GOVERNOR EXHAUST DESICCANT BED PURGE ORIFICE PURGE AIR EXTENDED PURGE PORT REAR RESERVOIR DELIVERY CHECK FRONT RESERVOIR DELIVERY PORT FIGURE 3 BENDIX AD 9si AIR DRYER WITH GOVERNOR PURGE CYCLE PURGE CYCLE Refer to Figures 3 and 5 When air brake system pressure reaches the cut out setting of the governor the integral governor unloads the compressor by supplying a pressure signal through the control port CON 2 4 This signal activates the purge cycle of the air dryer The governor unloads the compressor by allowing air pressure to fill the line leading to the compressor unloader mechanism This suspends the delivery of compressed air to the Bendix AD 9si air dryer Similarly the governor also supplies this air pressure signal to the purge valve The pressure moves the air dryer purge piston down opening the purge valve to atmosphere and closing off the compressor air supply to the turbo cut off valve described in the Turbo Cut off Feature section of this document Water and contaminants captured are expelled immediately when the purge valve opens In
8. 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 AD IS air dryer system a Bendix DRM dryer reservoir module or a Bendix 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 A A 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 fittings etc must be of equivalent size type and strength as original equipment and be designed specifically 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 s
9. to approximately 90 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 heater and thermostat assembly GENERAL When rebuilding or replacing components of the air dryer and reservoir use only genuine Bendix brand replacement parts For ease in servicing the AD 9si air dryer has been designed so that maintenance kits can be installed without removing the air dryer from the vehicle CAUTION Always depressurize the air dryer and purge volume by slowly removing the plug in port 22 and drain all other reservoirs on the vehicle to 0 psi before servicing the air dryer 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 shown in this manual or the Bendix Quick Reference Catalog for the appropriate kit s The Quick Reference Catalog BW1114 can be ordered and viewed on line at www bendix com Note Kits are not available for servicing components inside the air dryer purge volume DO NOT ATTEMPT TO REMOVE THE CLAMP BAND THAT RETAINS THE TWO HOUSINGS TOGETHER SERIOUS INJURY OR DEATH MAY OCCUR IF THESE INSTRUCTIONS ARE NOT FOLLOWED COMPLETELY BENDIX
10. to the standard Bendix AD 9si 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 9si air dryer The AD 9si PuraGuard oil coalescing air dryer has all of the same functions as the standard AD 9si air dryer and is used in applications where lower oil concentration levels are required IMPORTANT When servicing note that standard AD 9si air dryers or air dryer cartridges may be serviced with PuraGuard oil coalescing air dryers or cartridges however PuraGuard oil coalescing air dryers or cartridges MUST only be serviced with like replacements Note Unless otherwise stated in this document AD 9si air dryer refers to both the standard and PuraGuard oil coalescing air dryer The AD Qsi air dryer consists of a spin on desiccant cartridge secured to a base assembly The base assembly contains a delivery check valve assembly safety valve heater and thermostat assembly integrated governor in most assemblies threaded air connections internal purge volume and purge valve assembly The removable purge valve assembly incorporates the purge valve mechanism and a turbocharger cut off feature that is designed to prevent loss of engine turbo boost pressure during the purge cycle of the AD 9si air dryer For ease of maintenance all replaceable assemblies should be serviceable without removal of the air dryer from its mounting on the
11. vehicle provided adequate clearance exists between the air dryer and the vehicle components Refer to the Preventive Maintenance section of this document BENDIX AD 9si AIR DRYER OPERATION GENERAL Refer to Figures 2 through 5 The Bendix AD 9si air dryer is designed to receive compressed air from the vehicle air compressor clean and dry the air deliver air to the vehicle s air reservoirs and control the compressor dryer charge cycle The AD 9si air dryer is available with an internal governor Figures 2 and 3 or without an internal governor Figures 4 and 5 AIR DRYER OPERATION GENERAL The Bendix AD 9si air dryer alternates between two modes or cycles during operation the Charge Cycle and the Purge Cycle The following describes these cycles of operation Air Connection Port ID Function Connection Quantity Inlet Port air in OoOO O M _ TABLE 1 PORT DESIGNATIONS Ibi COMPRESSOR OIL COALESCING X FILTER CONTROL LINE CONTROL GOVERNOR EXHAUST Note 1 DESICCANT The Bendix AD 9si air dryer purge piston has BED a purge control channel drain This allows any condensation in this area to flow 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 PURGE ORIFICE PURGE AIR EXTENDED PURGE REAR RESERVOIR Pa PORT DELIVERY
12. AD 9si 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 Drain all reservoirs to O psi Identify and disconnect the three air lines from the air dryer housing 4 Unplug the vehicle wiring harness from the heater and thermostat assembly connector o Remove the three mounting bolts that secure the air dryer to the vehicle BENDIX AD 9si AIR DRYER INSTALLATION 1 Install the Bendix AD 9si air dryer on the vehicle using the three existing 1 2 13 UNC bolts Torque the bolts to 720 912 in Ibs If replacement bolts are necessary use grade 5 or above and ensure they are the same length as those originally used to install the dryer If the original air dryer is being reinstalled make sure the threads in the air dryer housing are in good condition 2 Reconnect the three air lines to the proper ports on the air dryer identified during step 3 of the Bendix AD 9si removal 3 Reconnect the vehicle wiring harness to the AD 9si air dryer heater and thermostat assembly connector by plugging it into the air dryer connector until its lock tab snaps in place 4 Before placing the vehicle back into service test the air dryer operation as indicated in Testing The Bendix
13. ALVE X 7j M O RING BODY SPRING GOVERNOR COVER SCREWS GOVERNOR WASHER V JJ O RING O RING 0 GOVERNOR KIT AA ____ PURGE VALVE ex VALVE TF EA 2 RETAINING gt RING FIGURE 7 BENDIX AD 9si AIR DRYER SERVICEABLE COMPONENTS that connects the air compressor discharge line to the air dryer inlet fitting Remove the air dryer delivery port fitting OUT 21 Using any necessary fittings install a Tee fitting in the air dryer delivery port To one side of the Tee fitting install the line removed from the air dryer delivery port to the opposite side of the Tee fitting install the line removed from the air dryer inlet port This procedure will allow the integral governor to continue to regulate the air brake system pressure properly After testing the Tee fitting for any air leakage by using a soap solution after charging to system cut out pressure a 1 bubble in 10 seconds is acceptable the vehicle may be returned to temporary service Note This is a temporary bypass of the air dryer Full repair of the unit must be carried out at the earliest opportunity Excessive vehicle operation with the air dryer bypassed may damage oil sensitive components such as an automated manual transmission or the emission system With the air dryer removed from the system contaminants will be entering the air brake system Reservoirs will need to be manually drained daily until the repairs are completed At the end of ea
14. ch working day park the vehicle and slowly drain pressure through the drain valves leave open to the atmosphere for several hours if possible When repairs are carried out be sure to check that all reservoirs are emptied of all contaminants 11 If after bypassing the air dryer the system pressure still does not build use the following procedure to remove clean and reinstall the delivery check valve DELIVERY CHECK VALVE CLEANING PROCEDURE Note This is only required if system pressure does not build after temporary bypass is completed Refer to Figure 7 throughout the following procedure De pressurize the air brake system following the general safety precautions outlined elsewhere in this document Also always de pressurize the air dryer purge reservoir before servicing the air dryer by slowly loosening the fitting that connects the air compressor discharge line to the air dryer inlet port This procedure does not require removal of the Bendix AD 9si air dryer from the vehicle 1 Remove the delivery check valve cover located directly above the delivery port OUT 21 2 The spring delivery check valve can now be removed 3 Remove and retain the o ring from the check valve body CLEANING amp INSPECTION 1 Use a suitable solvent to clean all metal parts and use a cotton swab to clean the bore Note Do not use abrasives or tools to clean the bore any scratches caused may necessitate replacing the B
15. dry air Use of these or other substances can damage the air dryer and may void the warranty 2 For the Bendix AD 9si air dryer there are no serviceable components or maintenance requirements that require the removal of the clamp band OPERATION amp LEAKAGE TESTS REFER TO THE TROUBLESHOOTING CHART IN THIS MANUAL 1 Check all lines and fittings leading to and from the air dryer for leakage and integrity Repair any leaks found 2 Build up system pressure to governor cut out and note that the Bendix AD 9si air dryer purges with an audible escape of air Watch the system pressure and note the pressure fall off for a ten minute period If pressure drop exceeds a for a single vehicle 1 psi minute from either service reservoir or b for tractor trailer 3 psi minute from either service reservoir inspect the vehicle air systems for leak sources and repair them Refer to the Symptoms 1 and 4 in the Troubleshooting Chart 3 CAUTION Be sure to wear safety glasses in case of a purge blast Check for excessive leakage around the purge valve with the compressor in the charge mode compressing air Apply a soap solution to the purge valve exhaust port and observe that leakage does not exceed a 1 bubble in one second If any leakage exceeds the maximum specified refer to Symptom 4 in the Troubleshooting Chart 4 Build up system pressure to governor cut out and note that the AD 9si air dryer purges with an audible burst of air f
16. e assembly prevents air pressure in the brake system from returning to the air dryer during the purge cycle After the purge cycle is complete the air dryer is ready for the next charge cycle to begin COMPRESSOR OIL COALESCING FILTER a a at Es M E 220 0 2 4 CONTROL PORT l TURBO CUT OFF VALVE CLOSED SUPPLY PORT n AERARII E E EXHAUST SAFETY VALVE DESICCANT BED PURGE ORIFICE PURGE AIR EXTENDED PURGE E PORT DELIVERY REAR RESERVOIR FRONT RESERVOIR DELIVERY PORT FIGURE 5 BENDIX AD 9si AIR DRYER WITHOUT GOVERNOR PURGE CYCLE TURBO CUT OFF FEATURE Refer to Figures 3 and 5 The primary function of the turbo cut off valve is to prevent loss of engine turbocharger air pressure through the Bendix AD 9si air dryer when the dryer is in the purge mode At the onset of the purge cycle the downward travel of the purge piston is stopped when the turbo cut off valve the tapered portion of the purge piston contacts its mating metal seat in the purge valve housing With the turbo cut off valve seated in the closed position air in the compressor discharge line as well as the AD 9si air dryer inlet port cannot enter the air dryer By completing these actions the turbo cut off effectively maintains turbocharger boost pressure to the engine PREVENTIVE MAINTENANCE Important Review the warranty policy before performing a
17. e is excessive leakage exceeding a 1 bubble in 5 seconds Re grease the seal on the air dryer cartridge before reinstalling C Defective governor C Check governor at both cut in and cut out position for proper pressures and excessive leakage at the exhaust D Compressor unloader mechanism D Remove air strainer or fitting from compressor inlet cavity leaking excessively With compressor unloaded check for unloader piston leakage Slight leakage is permissible 13 BENDDOAD 9si AIR DRYER TROUBLESHOOTING CHART 2 Water in vehicle reservoirs A Maximum air dryer inlet temperature is A Check for excessive carbon build up in compressor discharge exceeded due to improper discharge line Replace if required Make certain that discharge line line length length is at least 6 ft Increase discharge line length and or diameter to reduce air dryer inlet temperature B Ambient temperature exceeds 125 F B Relocate the air dryer away from excessive heat source C Air system charged from outside C If system must have outside air fill provision outside air should air source outside air not passing pass through the air dryer through air dryer D Excessive air usage Air dryer not D Refer to the Bendix Air Dryer Application Guideline BW2600 compatible with vehicle air system for proper application of the Bendix AD 9si air dryer An requirement improper air dryer extended purge reserv
18. endix AD 9si air dryer Superficial external corrosion and or pitting is acceptable 2 Clean the o rings with a clean dry cloth Do not use solvents 3 Inspect for physical damage to the bore and the check valve seat If the bore is damaged by scratches etc that would prevent the delivery check valve from seating replace the AD 9si air dryer 4 Inspect the delivery check valve o rings etc for wear or damage Replace if necessary using the check valve replacement kit available at any authorized Bendix parts outlets 12 ASSEMBLY 1 Lubricate the smaller o ring and check valve body with a heavy duty lithium grease Install the o ring on the check valve body by sliding the o ring over the set of four tapered guide lands The o ring groove holds the o ring in its correct location At the other end of the check valve body the spring is installed over the set of four straight guide lands When the spring has been pushed to the correct location the check valve body is designed to hold the end of the spring in position be sure that the spring is not loose before continuing with this installation Install the assembled check valve body o ring spring in the delivery port so that the o ring rests on its seat and the free end of the spring is visible 5 Grease the larger o ring and install it onto the cover Replace the delivery check valve cover and torque to 720 840 in lIbs Before placing the vehicle back in
19. n 2 or www bendix com for more information C The location of the air dryer is too close to the air compressor See the troubleshooting chart at the end of this document Symptom 2 Remedy A D In areas where more than a 30 range of temperature occurs in one day small amounts of water can temporarily accumulate in the air brake system due to condensation Under these conditions the presence of small amounts of moisture is normal HEATER amp THERMOSTAT CONNECTOR FIGURE 6 HEATER AND THERMOSTAT CONNECTOR For Bendix AD 9si 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 application 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 filter out every three 3 years or 300 000 miles The recommended intervals for trucks equipped with no
20. n Bendix compressors are six months 50 000 miles one year 100 000 miles and two years 200 000 miles respectively More frequent intervals may be required depending on a vehicle s age its compressor condition use of a non Bendix compressor the operating environment the vehicle s vocation and its usage In conjunction with these guidelines fleets can determine the functionality of their filters 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 specific air dryer for additional information Recommended intervals for trucks equipped with non Bendix compressors are six months 50 000 miles one year 100 000 miles and two years 200 000 miles respectively 1 Visually check for physical damage such as chafed or broken air and electrical lines and broken or missing parts 2 Check the Bendix AD 9si air dryer and mounting bolts for tightness See Figure 1 Re torque the three air dryer bolts to 720 912 in lbs 3 Perform the Operation amp Leakage Tests listed in this publication A WARNING 1 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
21. ny intrusive maintenance procedures An extended warranty may be voided if intrusive maintenance is performed during this period Purge valve and governor maintenance is permissible during the warranty period only when using a genuine Bendix AD 9si purge valve governor kit Because no two vehicles operate under identical conditions maintenance and maintenance intervals will vary Experience is a valuable guide in determining the best maintenance interval for any one particular operation Every 900 operating hours or 25 000 miles or three 3 months 1 Check for moisture in the air brake system by opening reservoir drain valves and checking for the presence of water If moisture is present the desiccant cartridge may require replacement however the following conditions can also cause water accumulation and should be considered before replacing the desiccant A An outside air source has been used to charge the system This air did not pass through the drying bed of the air dryer 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 Contact the Bendix TechTeam at1 800 AIR BRAKE 1 800 247 2725 optio
22. oir may be added for higher air usage vehicle application vehicles such as city buses and construction vehicles If the vehicle is equipped with high air usage accessories such as trailer pump off systems or central tire inflation the air for these accessories must by pass the air dryer E Desiccant requires replacement E Replace desiccant cartridge assembly See Bendix Air Dryer Application Guideline BW2600 for recommended service intervals due to excessive system leakage popping off or exhausting B System pressure too high gt 135 psi B Test with accurate gauge Replace the governor cartridge if air necessary C Excessive pressure pulsations from C Increase the volume in the discharge line This can be compressor Typical single cylinder accomplished by adding a 90 cubic inch or larger reservoir type between the compressor and the AD 9si air dryer Constant exhaust of airatair A Air dryer purge valve leaking A With compressor loaded apply soap solution on purge valve dryer purge valve exhaust excessively exhaust to test for excessive leakage Repair or replace or unable to build system purge valve as necessary pressure Charge mode B Purge valve frozen open faulty heater B Refer to paragraph 5 of the Operation and Leakage Tests for and thermostat wiring blown fuse heater and thermostat test C Defective AD 9si air dryer delivery C Refer to Symptom 1 Remedy B check valve E
23. ollowed immediately by approximately 40 seconds of air flowing out of the purge valve Apply and release the service brakes several times 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 If the system does not follow this pattern refer to Symptoms 5 and 6 in the Troubleshooting Chart 5 Check the operation of the air dryer heater and thermostat assembly during cold weather operation as follows A Electric Power to the Dryer Refer to Figure 4 With the ignition or engine kill switch in the RUN 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 connections of the female connector on the vehicle power lead 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 possible except in cold weather operation Turn off the ignition switch and cool the Heater and Thermostat assembly to below 40 Fahrenheit 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 Heater and Thermostat assembly
24. pecifically 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 DESCRIPTION The function of both the Bendix AD 9si air dryer and the Bendix AD 9si PuraGuard oil coalescing air dryer is to collect and remove air system contaminants in solid liquid and aerosol form before they enter the brake system The AD 9si includes a spin on style cartridge for easy servicing and most include a fully integrated governor to control air system charging The air dryer provides clean dry air to the components of the brake system which increases the life of the system and reduces maintenance costs The need for daily manual draining of the reservoirs is eliminated The Bendix AD 9si PuraGuard oil coalescing air dryer has an identical appearance
25. ssure gauge into the control port repair purge valve if necessary B See Causes B E and F for Symptom B Refer to Symptom 4 Remedies B E and F Peces o mtm Desiccant material being A Faulty dryer cartridge A Replace the Bendix AD 9si air dryer cartridge or AD 9si air expelled from air dryer purge dryer B Check the AD 9si air dryer mounting for looseness or damage Repair mounting and replace cartridge Check for proper compressor installation if symptoms persist replace compressor Refer to Bendix Advanced Troubleshooting Guide for Air Brake Compressor BW1971 A slight pinging sound may be heard during system build up when a single cylinder compressor is used If this sound is deemed objectionable it can be reduced substantially by increasing the discharge line volume This can be accomplished by adding a 90 cubic inch or larger reservoir between the compressor and the AD 9si air dryer Check the air hose from the AD 9si air dryer control port to the compressor for a missing kinked or restricted line Install or repair the air hose Repair or replace the compressor unloader 15 Log on and Learn from the Best On line training that s available when you are 24 7 365 Visit www brake school com SD 08 2433 2014 Bendix Commercial Vehicle Systems LLC a member of the Knorr Bremse Group 9 14 All Rights Reserved amp Printed on recycled paper
26. to service check to see that the system pressure now builds to full operational pressure BENDIX AD 9si AIR DRYER TROUBLESHOOTING CHART SYMPTOM CAUSE REMEDY 1 Dryer is constantly cycling A Excessive system leakage A Test for excessive system leakage Allowable leakage or purging observed at dash gauge Single vehicle 1 psi minute Tractor trailer 3 psi minute Using soap solution test vehicle for leakage at fittings drain valves and system valves and any accessories i e air suspension Repair or replace as necessary and retest the system B Defective delivery check valve B Build system pressure to governor cut out Wait 1 minute for completion of purge cycle Using soap solution at exhaust of purge valve leakage should not exceed a 1 bubble in less than 5 seconds If a rapid loss of pressure is found the following procedure will determine if the delivery check valve is malfunctioning Build system pressure to governor cut out and allow a full minute for the normal dryer purge cycle to empty the purge reservoir Switch off the engine and apply and release the brakes multiple times so that the system pressure reaches governor cut in The purge valve will return to its closed position Carefully remove the air dryer cartridge using a strap wrench and then test for air leaking through the center of the threaded boss by applying a soap solution to the area Replace the delivery check valve if ther
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