Cooling Plate

Valve Plate

Inlet Valve Open

Unloader Piston Down & Seated
Piston Moving Down FIGURE 5 - OPERATION - LOADED (INTAKE)

Discharge Valve

COOLING

Inlet Valve Closed

Air owing through the engine compartment from the action of the engine fan and the movement of the vehicle assists in cooling the compressor. Cooling ns are part of the crankcase/cylinder block casting. Coolant owing from the engine cooling system through connecting lines enters the head and passes through internal passages in the cylinder head and valve plate assembly and is returned to the engine. Proper cooling is important in minimizing discharge air temperatures. Figure 8 illustrates the coolant ow connections. See the tabulated technical data in the back of this manual for specic requirements.

PREVENTATIVE MAINTENANCE

Regularly scheduled maintenance is the single most important factor in maintaining the air brake charging system. Refer to Table A in the Troubleshooting section for a guide to various considerations that must be given to maintenance of the compressor and other related charging system components. Important Note: Review the warranty policy before performing any intrusive maintenance procedures. An extended warranty may be voided if intrusive maintenance is performed during this period.
Piston Moving Up FIGURE 6 - OPERATION - LOADED (COMPRESSION)

LUBRICATION

The vehicle's engine provides a continuous supply of oil to the compressor. Oil is routed from the engine to the compressor oil inlet. An oil passage in the crankshaft conducts pressurized oil to precision sleeve main bearings and to the connecting rod bearings. Spray lubrication of the cylinder bores, connecting rod wrist pin bushings, and ball type main bearings is obtained as oil is forced out around the crankshaft journals by engine oil pressure. Oil then falls to the bottom of the compressor crankcase and is returned to the engine through drain holes in the compressor mounting ange.
Unloader Piston Up & Unseated Air From Governor Unloader Port Valve Plate Air Inlet Port
EVERY 6 MONTHS, 1800 OPERATING HOURS OR AFTER EACH 50,000 MILES WHICHEVER OCCURS FIRST PERFORM THE FOLLOWING INSPECTIONS AND TESTS. AIR INDUCTION
BA-922 compressors are only permitted to be naturally aspirated - use of the engine turbocharger as an air source is not allowed.
Unloader Piston Up & Unseated
Air in Pistons Mostly Shuttles Back and Forth from One Piston to the Other During Unloaded Mode FIGURE 7 - OPERATION - UNLOADED 3

4. Remove the discharge and inlet ttings, if applicable, and note their position on the compressor to aid in reassembly. Note: If a cylinder head maintenance kit is being installed, stop here and proceed to PREPARATION FOR DISASSEMBLY. If replacing the compressor continue. 5. Remove any supporting bracketing attached to the compressor and note their positions on the compressor to aid in reassembly. 6. Remove the ange mounting bolts and remove the compressor from the vehicle. 7. Inspect gear and associated drive parts for visible wear or damage. Since these parts are precision tted, they must be replaced if they are worn or damaged. If replacing the compressor or replacing the drive gear, remove the drive gear from the compressor crankshaft using a gear puller. 8. If the compressor is being replaced stop here and proceed to "Installing The Compressor" at the end of the assembly procedure.
6. Remove the two bolts located in the center of the head. Gently tap the head, cooling plate and valve plate assembly with a soft mallet to break the gasket seal. Lift the cylinder head with cooling plate and valve plate assembly off the cylinder block. 7. Remove the metal reed valve/gasket (12). 8. Gently tap the head, cooling plate and valve plate assembly with a soft mallet to break the gasket seals. Then separate the cylinder head from the cooling plate and valve plate assembly and remove the gasket (11) between them. 9. Turn the aluminum cylinder head over to expose the interior portion of the head. Push the unloader piston (7) along with its o-rings (6, 8 & 9) out of the cylinder head.

CRANKCASE COVER

1. Remove the four crankcase cover cap screws securing the crankcase cover to the crankcase. Using a soft mallet, gently tap the crankcase cover to break the gasket seal. Remove the crankcase cover gasket (14).
PREPARATION FOR DISASSEMBLY
Remove the balance of road dirt and grease from the exterior of the compressor with a cleaning solvent. Mark the rear end cover or end cover adapter in relation to the crankcase. It is recommended but not specically necessary to mark the relationships of the cylinder head, cooling plate, valve plate assembly, crankcase and cylinder block assembly. A convenient method to indicate the above relationships is to use a metal scribe to mark the parts with numbers or lines. Do not use marking methods such as chalk that can be wiped off or obliterated during rebuilding. Prior to disassembly make certain that the appropriate kits and/or replacement parts are available. Refer to Figure 9 during the entire disassembly and assembly procedure.

DISCHARGE LINE

1. Inspect the discharge line for kinks, damage, or carbon deposits. Replace as necessary. See the advanced troubleshooting guide for more information. General Note: All torques specied in this manual are assembly torques and typically can be expected to fall off after assembly is accomplished. Do not re-torque after initial assembly torques fall unless instructed otherwise. A compiled listing of torque specications is presented on page 11 of this manual. INCH POUNDS TO FOOT POUNDS To convert inch pounds to foot pounds of torque, divide inch pounds by 12. 12 Inch Pounds = 1 Foot Pound Example: 12

ASSEMBLY

9. Install the balance piston spring (5) in the unloader piston (7), then install the small diameter of the balance piston (4) through the center of the spring. 10. Install the unloader cover gasket (3) on the cylinder head making certain the unloader vent passage and both screw holes align. 11. Position the unloader cover (2) on top of the balance piston (4) making certain the stamped logo is visible. 12. Press and hold the unloader cover (2) in place on the cylinder head and install both unloader cover cap screws (1). Torque the cover cap screws (1) from 62 to 71 inch pounds (7-8 Nm). Sequence
3, 9 8, 14 1, 15 2, 16 4, 10 6, 12
INSTALLING THE COMPRESSOR
1. If the compressor was removed for replacement, install the drive components. Torque the crankshaft nut to 220 - 254 foot pounds (210-290 Nm). 2. Install any supporting bracketing on the compressor in the same position noted and marked during removal. 3. Install the gasket on the drive ange of the compressor. Make certain oil supply or return holes in the gasket are properly aligned with the compressor and engine. Gasket sealants are not recommended. Secure the compressor on the engine and tighten the mounting bolts. 4. Install the discharge, inlet and governor adapter ttings, if applicable, in the same position on the compressor noted and marked during disassembly. Make certain the threads are clean and the fittings are free of corrosion. Replace as necessary. See the Torque Specications for various tting sizes and types of thread on page 11 of this manual. 5. Inspect all air, oil, and coolant lines and ttings before reconnecting them to the compressor. Make certain o-ring seals are in good or new condition. Tighten all hose clamps. 6. Clean oil supply line. Before connecting this line to the compressor. Run the engine briey to be sure oil is owing freely through the supply line. 7. Before returning the vehicle to service, perform the Operation and Leakage Tests specied in this manual. Pay particular attention to all lines reconnected during installation and check for air, oil, and coolant leaks at compressor connections. Also check for noisy operation.

Discharge Line

Optional Ping Tank Air Dryer
The Air Brake Charging System supplies the compressed air for the braking system as well as other air accessories for the vehicle. The system usually consists of an air compressor, governor, discharge line, air dryer, and service reservoir.
Optional Bendix PuraGuard System Filter or PuraGuard QC Oil Coalescing Filter

Compressor

(Governor plus Synchro valve for the Bendix DuraFlo 596 Compressor)

Governor

Service Reservoir

(Supply Reservoir)

Reservoir Drain
Regularly scheduled maintenance is the single most important factor in maintaining the air brake charging
Column 1 Typical Compressors Spec'd

(See footnote 7)

Table A: Maintenance Schedule and Usage Guidelines
Column 2 Discharge Line I.D. Length Column 3 Recommended Air Dryer Cartridge Replacement1 Column 4 Recommended Reservoir Drain Schedule2

Vehicle Used for:

Low Air Use
Compressor with less than 15% duty cycle

No. of Axles

Column 5 Acceptable Reservoir Oil Contents3 at Regular Drain Interval

1/2 in.

Bendix Tu-Flo 550 air compressor
6 ft. Recommended Every Month Max of every 90 days
e.g. Line haul single trailer w/o air suspension, air over hydraulic brakes.
Compressor with up to 25% duty cycle

5 or less

For oil carry-over control4 suggested upgrades:

5/8 in. 1/2 in.

9 ft. 9 ft.

Every 3 Years

e.g. Line haul single trailer with air suspension, school bus. High Air Use
e.g. Double/triple trailer, open highway coach/RV, (most) pick-up & delivery, yard or terminal jockey, off-highway, construction, loggers, concrete mixer, dump truck, re truck.
Bendix BA-921 air compressor
BASIC test acceptable range: 3 oil units per month. See appendix A.

5/8 in.

12 ft.
Bendix Tu-Flo 750 air compressor
For the BASIC Test Kit: Order Bendix P/N 5013711
12 ft. Every 2 Years BASIC test acceptable range: 5 oil units per month. See appendix A.
Bendix BA-922, or DuraFlo 596 air compressor

8 or less

15 ft.
Every Month 3/4 in. 12 ft. Every Year
e.g. City transit bus, refuse, bulk unloaders, low boys, urban region coach, central tire ination.

12 or less

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. To 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 sufcient cooling occurs, the oil-vapor condenses and can be removed by the air dryer. Discharge line upgrades are not covered under warranty. Note: To help prevent discharge line freeze-ups, shorter discharge line lengths or insulation may be required in cold climates. (See Bendix

Bulletins TCH-08-21 and TCH-08-22, 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. 6. Note: Compressor and/or air dryer upgrades are recommended in cases where duty cycle is greater than the normal range (for the examples above). 7. For correct compressor upgrades consult Bendix - Please note that because a compressor is listed in the same area of the chart does not necessarily mean that it would be a suitable candidate for upgrade purposes.
For Bendix Tu-Flo 550 and 750 compressors, unloader service is recommended every 250,000 miles.
Air Brake Charging System Troubleshooting
How to use this guide: Find the symptom(s) that you see, then move to the right to nd the possible causes (What it may indicate) and remedies (What you should do). Review the warranty policy before performing any intrusive compressor maintenance. Unloader or cylinder head gasket replacement and resealing of the bottom cover plate are usually permitted under warranty. Follow all standard safety procedures when performing any maintenance. WARNING! Please READ and follow these instructions to Look for: Normal - Charging system is working within normal range. Check - Charging system needs further investigation.
avoid personal injury or death: When working on or around a vehicle, the following general precautions should be observed at all times. 1. Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Always wear safety glasses. 2. Stop the engine and remove ignition key when working under or around the vehicle. When working in the engine compartment, the engine should be shut off and the ignition key should be removed. Where circumstances require that the engine be in operation, EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components. 3. 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. 4. If the work is being performed on the vehicles 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 an AD-IS air dryer system or a dryer reservoir module, be sure to drain the purge reservoir.

5. Following the vehicle manufacturers recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle. 6. Never exceed manufacturers recommended pressures. 7. 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. 8. Use only genuine Bendix replacement parts, components and kits. Replacement hardware, tubing, hose, ttings, etc. must be of equivalent size, type and strength as original equipment and be designed specically for such applications and systems. 9. Components with stripped threads or damaged parts should be replaced rather than repaired. Do not attempt repairs requiring machining or welding unless specically stated and approved by the vehicle and component manufacturer. 10. Prior to returning the vehicle to service, make certain all components and systems are restored to their proper operating condition. 11. For vehicles with Antilock 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.

Symptom:

1.0 Oil Test Card Results

What it may indicate:

Not a valid test.

What you should do:

Discontinue using this test. Do not use this card test to diagnose compressor "oil passing" issues. They are subjective and error prone. Use only the Bendix Air System Inspection Cup (BASIC) test and the methods described in this guide for advanced troubleshooting. The Bendix BASIC test should be the denitive method for judging excessive oil fouling/oil passing. (See Appendix A, on page 27 for a flowchart and expanded explanation of the checklist used when conducting the BASIC test.)

Bendix BASIC Test

2.0 Oil on the Outside of the Compressor 2.1 Oil leaking at compressor / engine connections:
Engine and/or other accessories leaking onto compressor. (a) Leak at the front or rear (fuel pump, etc.) mounting ange. (b) Leak at air inlet tting. (c) Leak at air discharge tting. (d) Loose/broken oil line ttings.
Find the source and repair. Return the vehicle to service. Repair or replace as necessary. If the mounting bolt torques are low, replace the gasket. Replace the tting gasket. Inspect inlet hose and replace as necessary. Replace gasket or tting as necessary to ensure good seal. Inspect and repair as necessary.

2.2 Oil leaking from compressor:
(a) Excessive leak at head gasket. (b) Leak at bottom cover plate. (c) Leak at internal rear flange gasket. (d) Leak through crankcase. (e) (If unable to tell source of leak.)
Go to Test 1 on page 24. Reseal bottom cover plate using RTV silicone sealant. Replace compressor. Replace compressor. Clean compressor and check periodically.

(a) (c)

Head gaskets and rear ange gasket locations.
3.0 Oil at air dryer purge/exhaust or surrounding area
Air brake charging system functioning normally.
Air dryers remove water and oil from the air brake charging system. Check that regular maintenance is being performed. Return the vehicle to service. An optional kit (Bendix piece number 5011327 for the Bendix AD-IS or AD-IP air dryers, or 5003838 for the Bendix AD-9 air dryer) is available to redirect the air dryer exhaust.
4.0 Oil in Supply or Service Reservoir (air dryer installed)
Maintenance (a) If air brake charging system maintenance has not been performed. That is, reservoir(s) have not been drained per the schedule in Table A on page 13, Column 4 and/or the air dryer maintenance has not been performed as in Column 3. (b) If the vehicle maintenance has been performed as recommended in Table A on page 13, some oil in the reservoirs is normal.
(If a maintained Bendix PuraGuard system lter or Bendix PuraGuard QC oil coalescing lter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.)
Drain all air tanks and check vehicle at next service interval using the Bendix BASIC test. See Table A on page 13, column 3 and 4, for recommended service schedule.
See Table A, on page 13, for maintenance schedule information. Drain all air tanks (reservoirs) into the Bendix BASIC test cup. (Bendix kit P/N 5013711).
Drain all air tanks into Bendix BASIC test cup (Bendix Air System Inspection Cup). If less than one unit of reservoir contents is found, the vehicle can be returned to service. Note: If more than one oil unit of water (or a cloudy emulsion mixture) is present, change the vehicle's air dryer, check for air system leakage (Test 2, on page 24), stop inspection and check again at the next service interval. See the BASIC test kit for full details. If less than one "oil unit" of water (or water/ cloudy emulsion mixture) is present, use the BASIC cup chart on the label of the cup to determine if the amount of oil found is within the acceptable level. If within the normal range, return the vehicle to service. For vehicles with accessories that are sensitive to small amounts of oil, consider a Bendix PuraGuard QC oil coalescing lter. If outside the normal range go to Symptom 4.0(c). Also see the Table A on page 13, column 3 for recommended air dryer cartridge replacement schedule.

Duty cycle too high (c) Air brake system leakage. (d) Compressor may be undersized for the application. The duty cycle is the ratio of time the compressor spends building air to total engine running time. Air compressors are designed to build air (to "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 ttings, connections, lines, chambers or valves, etc. Go to Test 2 on page 24. See Table A, column 1, on page 13 for recommended compressor sizes. If the compressor is "too small" for the vehicle's role (for example, where a vehicle's use 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. If the compressor is correct for the vehicle, go to Symptom 4.0 (e).
4.0 Oil in Supply or Service Reservoir* (air dryer installed) (continued)
Temperature (e) Air compressor discharge and/or air dryer inlet temperature too high. (f) Insufcient coolant ow.
Check temperature as outlined in Test 3 on page 24. If temperatures are normal go to 4.0(h). Inspect coolant line. Replace as necessary (I.D. is 1/2"). Inspect the coolant lines for kinks and restrictions and ttings for restrictions. Replace as necessary. Verify coolant lines go from engine block to compressor and back to the water pump. Repair as necessary. If discharge line is restricted or more than 1/16" carbon build up is found, replace the discharge line. See Table A, column 2, on page 13 for recommended size. Replace as necessary. The discharge line must maintain a constant slope down from the compressor to the air dryer inlet tting to avoid low points where ice may form and block the ow. If, instead, ice blockages occur at the air dryer inlet, insulation may be added here, or if the inlet tting is a typical 90 degree tting, it may be changed to a straight or 45 degree tting. For more information on how to help prevent discharge line freeze-ups, see Bendix Bulletins TCH-0821 and TCH-08-22 (Appendix B). Shorter discharge line lengths or insulation may be required in cold climates.
Testing the temperature at the discharge tting.
Inspecting the coolant hoses.
(g) Restricted discharge line. (g)
Kinked discharge line shown.
Other (h) Restricted air inlet (not enough air to compressor). (h) 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 lter and service if necessary (if possible, check the air lter usage indicator).

12.0 Air dryer safety valve releases air. Air dryer safety valve
(a) Restriction between air dryer and reservoir. (b) Air dryer safety valve malfunction. (c) Air dryer maintenance not performed. (d) Air dryer malfunction.
Inspect delivery lines to reservoir for restrictions and repair as needed. Verify relief pressure is at vehicle or component manufacturer specications. Replace if defective. See Maintenance Schedule and Usage Guidelines (Table A, column 3, on page 13). Verify operation of air dryer. Follow vehicle O.E. maintenance recommendations and component Service Data information. Go to Test 5 on page 25. Go to Test 4 on page 25. Verify relief pressure is at vehicle or component manufacturer's specications (typically 150 psi). Replace if defective. Go to Test 4 on page 25. Go to Test 6 on page 25. Verify operation of air dryer. Follow vehicle O.E. maintenance recommendations. Go to Test 4 on page 25. Go to Test 2 on page 24. Go to Test 5 on page 25. Available reservoir capacity may be reduced by build up of water etc. Drain and perform routine maintenance per Table A, columns 3 & 4, on page 13. Go to Test 6 on page 25. Verify operation of air dryer. Follow vehicle O.E. maintenance recommendations and component Service Data information. Go to Test 2 on page 24.
Technician removes governor.
13.0 Reservoir safety valve releases air
14.0 Air dryer doesnt purge. (Never hear exhaust from air dryer.)
15.0 Compressor constantly cycles (compressor remains unloaded for a very short time.)
(e) Improper governor control line installation to the reservoir. (f) Governor malfunction. (a) Reservoir safety valve malfunction. (b) Governor malfunction. (c) Compressor unloader mechanism malfunction. (a) Air dryer malfunction. (b) Governor malfunction. (c) Air brake system leakage. (d) Improper governor control line installation to the reservoir. (a) A i r b r a k e c h a r g i n g s y s t e m maintenance not performed.
(b) Compressor unloader mechanism malfunction. (c) Air dryer purge valve or delivery check valve malfunction. (d) Air brake system leakage.
16.0 Compressor leaks air
(a) Compressor leaks air at connections or ports. (b) Compressor unloader mechanism malfunction. (c) Damaged compressor head gasket(s).
Check for leaking, damaged or defective compressor ttings, gaskets, etc. Repair or replace as necessary. Go to Test 6 on page 25. An air leak at the head gasket(s) may indicate a downstream restriction such as a freeze-up or carbon blockage and/or could indicate a defective or missing safety valve. Find blockage (go to 9.0(f) for details) and then replace the compressor. Do not reuse the safety valve without testing. See Symptom 12.0(a).

The Technician checks boxes for any of the complaints that can be conrmed.
* Note: A conrmed complaint
above does NOT mean that the compressor must be replaced. The full BASIC test below will investigate the facts.
We will measure amount currently found when we get to step B of the test.
Excessive engine oil loss amount described: ______________ Is the engine leaking oil? no yes* Is the compressor leaking oil? no yes* Other complaint: _____________________________________ No customer complaint.

BASIC test starts here:

STEP A - Select one:
This is a low air use vehicle: Line haul (single trailer) with 5 or less axles, or This is a high air use vehicle: Garbage truck, transit bus, bulk unloader, or line haul with more than 5 axles. Then go to Step B.
The Technician selects the air use category for the vehicle. This decided which of the two acceptance lines on the cup will be used for the test below. For an accurate test, the contents of all the air tanks on the vehicle should be used. Note for returning vehicles that are being retested after a water/cloudy emulsion mixture was found last time and the air dryer cartridge replaced: If more than one oil unit of water or a cloudy emulsion mixture is found again, stop the BASIC test and consult the air dryer's Service Data sheet troubleshooting section.
STEP B - Measure the Charging System Contents
1. Park and chock vehicle on level ground. Drain the air system by pumping the service brakes. 2. Completely drain ALL the air tanks into a single BASIC cup. 3. If there is less than one unit of contents total, end the test now and return the vehicle to service. Vehicle passes. 4. If more than one oil unit of water (or a cloudy emulsion mixture) is found: (a) Change the vehicles air dryer cartridge Oil - see Footnote 1, Units (b) Conduct the 4 minute leakage test (Step D), (c) STOP the inspection, and check the vehicle again after 30 days - see Footnote 2. STOP Otherwise, go to Step C.
Footnote 1: Note: Typical air dryer cartridge replacement schedule is every 3 yrs/ 300K miles for low air use vehicles and every year/100K miles for high air use vehicles. Footnote 2: To get an accurate reading for the amount of oil collected during a 30 day period, ask the customer not to drain the air tanks before returning. (Note that 30-90 days is the recommended air tank drain schedule for vehicles equipped with a Bendix air dryer that are properly maintained.) If, in cold weather conditions, the 30 day air tank drain schedule is longer than the customer's usual draining interval, the customer must determine, based on its experience with the vehicle, whether to participate now, or wait for warmer weather. See the cold weather tips in Bulletins TCH-008-21 and TCH008-22 (included in Appendix B of the advanced troubleshooting guide). 27

STEP E - If no air leakage was detected in Step D
Replace the compressor. Note: If the compressor is within warranty period, please follow standard warranty procedures. Attach the completed checklist to warranty claim.
The Technician only reaches Step E if the amount of oil found, for the amount of time since the air tanks were last drained exceeds the acceptance level, AND the vehicle passes the four-minute leakage test (no noticeable leakage was detected).

Appendix B

Technical Bulletin
Bulletin No.: TCH-008-021 Effective Date: 11/1/92

Page: 1 of 2

Subject: Air
Brake System - Cold Weather Operation Tips
As the cold weather approaches, operators and eets alike begin to look to their vehicles with an eye toward winterization, and particularly what can be done to guard against air system freeze-up. Here are some basic Tips for operation in the cold weather. Engine Idling Avoid idling the engine for long periods of time! In addition to the fact that most engine manufacturers warn that long idle times are detrimental to engine life, winter idling is a big factor in compressor discharge line freeze-up. Discharge line freeze-ups account for a signicant number of compressor failures each year. The discharge line recommendations under Discharge Lines are important for all vehicles but are especially so when some periods of extended engine idling can not be avoided. Discharge Lines The discharge line should slope downward from the compressor discharge port without forming water traps, kinks, or restrictions. Cross-overs from one side of the frame rail to the other, if required, should occur as close as possible to the compressor. Fitting extensions must be avoided. Recommended discharge line lengths and inside diameters are dependent on the vehicle application and are as follows.
Typical P&D, School Bus and Line Haul
The maximum discharge line length is 16 feet.
Length 6.0-9.5 ft. 9.5-12 ft.

I.D. Min. in. in.

Other Requirements None Last 3 feet, including tting at the end of the discharge line, must be insulated with inch thick closed cell polyethylene pipe insulation. Last 3 feet, including tting at the end of the discharge line, must be insulated with inch thick closed cell polyethylene pipe insulation.

12-16 ft.

If the discharge line length must be less than 6 feet or greater than 16 feet, contact your local Bendix representative.

Appendix B: Continued

Bulletin No.: TCH-008-021 Effective Date: 11/1/92 Page: 2 of 2

Bulletin No.: TCH-008-022 Effective Date: 1/1/1994

Page: 1 of 1

Subject: Additional
Cold Weather Operation Tips for the Air Brake System
Last year we published Bulletin PRO-08-21 which provided some guidelines for winterizing a vehicle air brake system. Here are some additional suggestions for making cold weather vehicle operation just a little more bearable. Thawing Frozen Air Lines The old saying; Prevention is the best medicine truly applies here! Each year this activity accounts for an untold amount of unnecessary labor and component replacement. Here are some Dos and Donts for prevention and thawing. Dos 1. Do maintain freeze prevention devices to prevent road calls. Dont let evaporators or injectors run out of methanol alcohol or protection will be degraded. Check the air dryer for proper operation and change the desiccant when needed. 2. Do thaw out frozen air lines and valves by placing the vehicle in a warmed building. This is the only method for thawing that will not cause damage to the air system or its components. 3. Do use dummy hose couplings on the tractor and trailer. 4. Do check for sections of air line that could form water traps. Look for drooping lines. Donts 1. Do not apply an open ame to air lines and valves. Beyond causing damage to the internal nonmetallic parts of valves and melting or burning non-metallic air lines. WARNING: THIS PRACTICE IS UNSAFE AND CAN RESULT IN VEHICLE FIRE! 2. Do not introduce (pour) uids into air brake lines or hose couplings (glad hands). Some uids used can cause immediate and severe damage to rubber components. Even methanol alcohol, which is used in Alcohol Evaporators and Injectors, should not be poured into air lines. Fluids poured into the system wash lubricants out of valves, collect in brake chambers and valves and can cause malfunction. Loss of lubricant can affect valve operating characteristics, accelerate wear and cause premature replacement. 3. Do not park a vehicle outside after thawing its air system indoors. Condensation will form in the system and freeze again. Place the vehicle in operation when it is removed to the outdoors. Supporting Air and Electrical Lines Make certain tie wraps are replaced and support brackets are re-assembled if removed during routine maintenance. These items prevent the weight of ice and snow accumulations from breaking or disconnecting air lines and wires. Automatic Drain Valves (System without Air Dryer) As we stated last year, routine reservoir draining is the most basic step (although not completely effective) in reducing the possibility of freeze-up. While automatic drain valves relieve the operator of draining reservoirs on a daily basis, these valves MUST be routinely checked for proper operation. Dont overlook them until they fail and a road call is required.

BWBendix Commercial Vehicle Systems LLC. All rights reserved. 10/2005. Printed in U.S.A.

compressors

BENDIX BA-922 SAE UNIVERSAL FLANGE AIR COMPRESSOR
High output compressed air generation for ultra demanding commercial & industrial applications.

Experience Counts

For generations, Bendix Commercial Vehicle Systems (Bendix CVS) has been leading the way in air charging system experience and expertise. More fleets specify our hard-working products and systems than any other. Bendix CVS continues its legacy of quality, reliability and durability with a next generation high-performing, energy-saving compressor option the Bendix BA-922 SAE Universal Flange compressor.
Ideal for niche industrial, agricultural, and petroleum applications, the universal flange model.
Features an adapter mount to meet SAE J744
hydraulic pump, engine & motor mounting, and drive dimensions standards;
An Ideal Solution For A Wide Range Of Unique Applications
Utilizing a standard SAE B Flange, and a 15-tooth BB spline for strength, the Bendix BA-922 SAE compressor is designed to address a wide variety of commercial and industrial applications. Its clock-able front adapter allows the compressor to be easily mounted in several different positions depending on your requirement.
be mounted at several different angles depending on physical constraints and application necessities; and driven by an engine PTO, hydraulic motor, or electric motor. Option for belt drive as well.
Building On The Power Of The Bendix BA-922 Compressor:
High Air Delivery A dependable workhorse, the Bendix BA-922 compressor provides maximum air delivery even at low speeds. Its high-output, two-cylinder design supplies 32 cfm (cubic feet per minute) displacement at 1,250 rpm (revolutions per minute). Power like this delivers the ability to recharge the system quickly and efficiently even at low speeds making it ideal for more demanding brake system applications. Thats important, since high output results in lower duty cycle, and lower duty cycle results in longer compressor life. High Thru-Drive Unlike other high-air-output compressors, the Bendix BA-922 compressors standard design is capable of powering a 25 horsepower accessory, while the SAE Universal Flange model incorporates a built in 9-tooth SAE A spline in the rear for an accessory pump or drive. Effective Cooling Systems The cylinder head of this hard working unit provides lower discharge air temperatures by incorporating highly effective cooling surfaces, thus reducing carbon formation and producing higher air quality. Minimizing discharge temperature increases the service life of downstream air components, such as the air dryer and valves. Compact, Lightweight Design Highly efficient, the Bendix BA-922 two-cylinder compressor replaces earlier four-cylinder designs. While its volume output is similar to the Bendix Tu-Flo 1400 compressor, the unit is 4 inches shorter and weighs 33 percent less thanks to its optimized design and aluminum components. What's more, its compact size enables it to meet even the most demanding installation constraints in tight engine compartments without compromising its high-air-output capability.
We're proud of our reputation as experts in air brake systems and leading-edge safety technologies in North America. No one understands the intricacies of the system like we do. By focusing on the entire system not just one part Bendix offers efcient, trouble-free operation plus a system that offers you: Reduced Maintenance Improved Performance Simple, Integrated Design Fewer Leak Points
Bendix Quality and Service Guaranteed
Bendix stands behind every compressor with complete warranty protection and a veteran technical support team to help you troubleshoot and resolve any air brake system challenges. In addition to the sales and service professionals you deal with face-to-face, there's an entire team working behind the scenes to produce top quality Bendix products on which you can depend. From all across our organization, rest assured you have nearly 80 years of practical experience hard at work for you.

The Bendix BA-922 SAE Universal Flange Air Compressor

FEATURES

High air output

BENEFITS

Provides ample air for more demanding applications Effective cylinder head cooling results in very low discharge air temperature Improves durability and reliability while reducing maintenance costs Compact size to meet tight OE installation constraints Improves vehicle fuel economy and performance

Effective cooling system

Simple, two-cylinder configuration Smaller size
Typical Trucking Applications
Bulk haulers Double & triple combination vehicles Refuse haulers Cement mixers Off-highway vehicles, including construction, mining, and agricultural models Transit coaches

Lighter weight

Discharge Air Temperature
(0 psig inlet pressure; 120 psig discharge pressure)
Discharge Air Temperature (degrees in Fahrenheit)
Bendix BA-922 SAE Universal Flange Compressor Specifications
Typical weight Number of cylinders Bore Diameter Stroke Calculated displacement at 1250 RPM Flow Capacity @ 1800 RPM & 120 PSI Flow Capacity @ 3000 RPM & 120 PSI Maximum recommended RPM Minimum coolant flow maximum RPM Approximate horsepower required: Loaded 1800 RPM at 120 PSIG Unloaded 1800 RPM Maximum inlet air temperature Maximum discharge air temperature Minimum oil pressure required Minimum oil-supply line size Minimum unloader-line size Minimum Governor Cutout Pressure Input Drive: Output Drive: 8.73 HP 1.96 HP 170F 350F 15 PSI 3/16" I.D. 3/16" I.D. 120 PSI 15 tooth SAE Universal Flange spine (male or female) 9 tooth SAE A female English or metric threads for fitting installation 60 lbs. 2 3.622 in. (95.005 mm) 2.125 in. (53.970 mm) 31.7 CFM 25.2 CFM 38.4 CFM 3000 RPM 2.0 Gals./Min.

BA-922 Compressor

100 600

Compressor Speed (rpm)

Air Flow

Air Flow (CFM)

Bendix compressors provide the power that keeps you on the road, and the value that keeps you coming back.
The Bendix BA-922 SAE Universal Flange compressor is part of the complete line of reliable, durable Bendix air brake components that can help improve vehicle performance, increase efficiency, and reduce your overall operating costs. Find out what Bendix air power can do for you. Talk to your Bendix Account Manager, call 1-800-AIR-BRAKE (1-800-247-2725), or visit www.bendix.com.
Bendix Commercial Vehicle Systems LLC 901 Cleveland Street Elyria, OH 44035 1-800 AIR-BRAKE (1-800-247-2725) BWBendix Commercial Vehicle Systems LLC, a member of the Knorr-Bremse Group 10/09 All Rights Reserved Printed in U.S.A.