BENDIX SD-01-700 User Manual

BENDIX® BA-922® COMPRESSOR

SD-01-700

DESCRIPTION

The function of the air compressor is to provide and maintain air under pressure to operate devices in the air brake systems. The Bendix® BA-922® compressor is a two cylinder, reciprocating compressor with a rated displacement of 31.6 cubic feet per minute at 1250 RPM.

The compressor consists of a water-cooled cylinder head, cooling plate, valve plate assembly, and an integral air cooled crankcase and cylinder block. The cast aluminum cylinder head contains the required air and water ports as well as two unloader pistons. The cast aluminum cooling plate provides added cooling and is located between the cylinder head and valve plate assemblies. The valve plate assembly consists of laminated, brazed steel plates which incorporate various valve openings and channels for conducting air and engine coolant into and out of the cylinder head.

The discharge valves are part of the valve plate assembly . The cylinder head, with the cooling and valve plates, comprise a complete cylinder head assembly.

The cast iron crankcase and cylinder block assembly houses the pistons, connecting rods, crankshaft and related bearings.

Air

Safety

Valve

Crankcase and

Cylinder Block

Unloader (2)

Cylinder

Head

Valve Plate

Assembly

FIGURE 1 - BENDIX® BA-922® COMPRESSOR

Delivery

Port

Intake

While not all compressors and charging systems are equipped with an optional discharge line safety valve, this component is recommended. The discharge line safety valve is installed in the cylinder head – or close to the compressor discharge port – and protects against over pressurizing the compressor in the event of a discharge line freeze up or blockage.

OPERATION

The compressor is driven by the vehicle engine and functions continuously while the engine is in operation. Actual compression of air is controlled by the compressor unloading mechanism operating in conjunction with a governor.

Unloader

Port

Cooling

Plate

Piston

Crankshaft

FIGURE 2 - BENDIX® BA-922® COMPRESSOR (CUT-AWAY)

Piston Rod

Discharge

Reed

Valves

Caterpillar

Detroit

Diesel

Detroit

Diesel

John

Deere

FIGURE 3 - TYPICAL COMPRESSOR DRIVE FLANGES

AIR INTAKE (LOADED)

During the piston down stroke, a vacuum is created in the cylinder bore above the piston. The vacuum causes the inlet reed valve to ﬂ ex open. Atmospheric air ﬂ ows through the open inlet valve and ﬁ lls the cylinder bore above the piston.

AIR COMPRESSION (LOADED)

When the piston reaches approximately bottom dead center (BDC), the inlet reed valve closes. Air above the piston is trapped by the closed inlet reed valve and is compressed as the piston begins to move toward top dead center (TDC). When air in the cylinder bore reaches a pressure greater than that of the system pressure, the discharge reed valves open and air ﬂ ows into the discharge line and air brake system.

Air, during the compression stroke, ﬂ ows into the hollow center of the unloader piston through an opening in the end of the piston. Compressed air acts on the interior surfaces of the unloader piston and, along with the unloader piston spring, holds the unloader piston against its seat on the valve plate. See Figure 6.

cavity and into the other cylinder. A small amount of air moves out of the inlet port. On the piston down stroke (TDC to BDC), air ﬂ ows in the reverse direction; from the other cylinder through the unloader piston to the inlet cavity , past the unseated unloader piston and into the cylinder bore.

Governor

Unloader Port

Reservoir

Port

Compressor

FIGURE 4 - BENDIX®BA-922® COMPRESSOR UNLOADER SYSTEM

Air

Discharge

Port

Air Inlet

Port

Air Dryer

Supply Reservoir

Discharge

Valve

Closed

Unloader

Port

NON-COMPRESSION OF AIR (UNLOADED)

When air pressure in the supply reservoir reaches the cut-out setting of the governor, the governor delivers system air to the compressor unloader port. Air entering the unloader port acts on the unloader piston, causing it to move away from its seat on the valve plate assembly. When the unloader piston is unseated a passage is opened between the cylinder bore, the air inlet cavity in the cylinder head, and the other cylinder. Air compression ceases. See Figure 7.

As the piston moves from bottom dead center (BDC) to top dead center (TDC), air in the cylinder bore ﬂ ows past the unseated unloader piston, into the cylinder head inlet

Cooling

Plate

Valve Plate

Inlet Valve Open

Piston Moving Down

FIGURE 5 - OPERATION - LOADED (INTAKE)

Unloader

Piston

Down &

Seated

Air Inlet

Air

Discharge

Port

Valve

Plate

Inlet

Valve

Closed

FIGURE 6 - OPERATION - LOADED (COMPRESSION)

Port

Discharge

Valve Open

Piston Moving Up

Unloader

Port

Unloader

Piston

Down &

Seated

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 ﬂ ange.

COOLING

Air ﬂ owing through the engine compartment – from the action of the engine fan and the movement of the vehicle – assists in cooling the compressor. Cooling ﬁ ns are part of the crankcase/cylinder block casting. Coolant ﬂ 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 ﬂ ow connections. See the tabulated technical data in the back of this manual for speciﬁ c 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.

EVERY 6 MONTHS, 1800 OPERATING HOURS, OR AFTER EACH 50,000 MILES – WHICHEVER OCCURS FIRST – PERFORM THE FOLLOWING INSPECTIONS AND TESTS.

AIR INDUCTION

Bendix® 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 From

Governor

Unloader

Port

Valve

Plate

Air in Pistons Mostly Shuttles Back

and Forth from One Piston to the

Other During Unloaded Mode

FIGURE 7 - OPERATION - UNLOADED

Air Inlet Port

Unloader

Piston

Up &

Unseated

A supply of clean air is one of the single most important factors in compressor preventative maintenance. Since the Bendix® BA-922® compressor receives supply air from the engine air ﬁ lter, periodic maintenance of the engine air ﬁ lter is necessary.

Inspect the compressor intake adapter, and the connecting hoses each time engine air cleaner maintenance is performed.

1. Inspect the intake hose adapters for physical damage. Make certain to check the adapters at both ends of the intake hose or tubing.

2. Inspect the intake hose clamps and tighten them if needed.

3. Inspect the intake hose or line for signs of drying, cracking, chafing and ruptures, and replace it as necessary.

COMPRESSOR COOLING

Inspect the compressor discharge port, inlet cavity, and discharge line for evidence of restrictions and carbon build-up. If more than 1/16" of carbon is found, thoroughly clean or replace the affected parts. Since carbon build-up generally indicates inadequate cooling, closely inspect the compressor cooling system. Check all compressor coolant lines for kinks and restrictions to ﬂ ow. Minimum coolant line size is 3/8" I.D. Check coolant lines for internal clogging from rust scale. If coolant lines appear suspicious, check the coolant ﬂ ow and compare to the tabulated technical data in the back of this manual. Carefully inspect the air induction system for restrictions.

LUBRICATION

Check the external oil supply line for kinks, bends, or restrictions to ﬂ ow. I.D.

Refer to the tabulated technical data in this manual

Supply lines must be a minimum of 3/16"

(page 10) for oil pressure minimum values. Check the exterior of the compressor for the presence of

oil seepage and refer to the TROUBLESHOOTING section (page 11) for appropriate tests and corrective action.

OIL PASSING

All reciprocating compressors pass a minimal amount of oil. Air dyers will remove the majority of oil before it can enter the air brake system. For particularly oil sensitive systems, the Bendix® PuraGuard® system ﬁ lter can be used in conjunction with a Bendix air dryer.

If compressor oil passing is suspected, refer to the TROUBLESHOOTING section and T ABLE A (page 13) for the symptoms and corrective action to be taken. In addition, Bendix has developed the “Bendix Air SystemInspection Cup” or BASIC kit to help substantiate suspected excessive oil passing. The steps to be followed when using the

Head

Bolt (6)

Inlet Port

Coolant In or Out

The cylinder head connection ports are identiﬁ ed with cast in numerals as follows:

(Compressors with no signal line to the unloader port should

FIGURE 8 - TYPICAL BA-922® COMPRESSOR CYLINDER

HEAD

Discharge

Safety Valve

CYLINDER HEAD PORT IDENTIFICATION

Atmospheric AIR IN 0 Compressed AIR OUT 21 Coolant IN or OUT 91 and 92 Governor Control 41

have a vent installed in the port rather than a plug.)

Unloader

Covers

Discharge

Port

Coolant In or

Out

Governor

Connection

BASIC kit are presented in APPENDIX A at the end of the TROUBLESHOOTING section.

COMPRESSOR DRIVE

Check for noisy compressor operation, which could indicate excessive drive component wear. Adjust and/or replace as necessary. Check all compressor mounting bolts and retighten evenly if necessary. Check for leakage and proper unloader mechanism operation. Repair or replace parts as necessary.

COMPRESSOR UNLOADER & GOVERNOR

Test and inspect the compressor and governor unloader system for proper operation and pressure setting.

1. Check for leakage at the unloader port. Replace leaking or worn o-ring.

2. Make certain the unloader system lines are connected as illustrated in Figure 3.

3. Cycle the compressor through the loaded and unloaded cycle several times. Make certain that the governor cuts in (compressor resumes compressing air) at a minimum of 105 psi (cut-out should be approximately 15-20 psi greater than cut-in pressure). Adjust or replace the governor as required.

4. Note that the compressor cycles to the loaded and unloaded conditions promptly. If prompt action is not noted, repair or replace the governor and/or repair the compressor unloader.

IMPORTANT NOTE

Replacement air governors must have a minimum cut-in pressure of 105 psi. The cut-in pressure is the

lowest system pressure registered in the gauges before the compressor resumes compressing air.

Compressors with no signal line to the unloader port should have a vent installed in the port rather than a plug.

SERVICE TESTS: GENERAL

The following compressor operating and leakage tests need not be performed on a regular basis. These tests should be performed when it is suspected that leakage is substantially affecting compressor buildup performance, or when it is suspected that the compressor is “cycling” between the load and unloaded modes due to unloader plunger leakage.

Note: When comparing build-up times, be sure to make an allowance for any air system modiﬁ cations which could cause longer times, such as adding air components or reservoirs. Always check for air system leakage.

LEAKAGE TESTS

See the standard Air Brake System and Accessory Leakage test on Page 24 (Test 2).

Note: Leakage in the air supply system (components before the supply reservoir - such as the governor, air dryer , reservoir drain cocks, safety valve and check valves) will not be registered on the vehicle dash gauges and must be tested separately. Refer to the various maintenance manuals for individual component leakage tests, and the Bendix “Test and Checklist” published in the Air Brake System Handbook (BW5057) and on the back of the Dual Circuit Brake System Troubleshooting card (BW1396).

IN-SERVICE OPERATING TESTS

Compressor Performance: Build-up Test

This test is performed with the vehicle parked and the engine operating at maximum recommended governed speed. Fully charge the air system to governor cut-out (air dryer purges). Pump the service brake pedal to lower the system air pressure below 80 psi using the dash gauges. As the air pressure builds back up, time from when the dash air pressure gauge passes 85 to the time it passes 100 psi. The time should not exceed 40 seconds. If the vehicle exceeds 40 seconds, test for (and ﬁ x) any air leaks and then re-test the compressor performance. If the vehicle does not pass the test the second time, use the Advanced Troubleshooting Guide for Air Brake Compressors – starting on page 1 1 of this document – to assist your investigation of the cause(s).

Note: All new vehicles are certiﬁ ed using the FMVSS 121 test (paragraph S5.1.1) by the vehicle manufacturer, however the above test is a useful guide for in-service vehicles.

Optional Comparative Performance Check

It may be useful to also conduct the above test with the engine running at high idle (instead of maximum governed speed), and record the time taken to raise the system pressure a selected range (for example, from 90 to 120 psi, or from 100 to 120 psi, etc.) and record it in the vehicle’s maintenance ﬁ les. Subsequent build-up times throughout the vehicle’s service life can then be compared to the ﬁ rst one recorded. (Note: the 40 second guide in the test above does not apply to this build-up time.) If the performance degrades signiﬁ cantly over time, you may use the Advanced Troubleshooting Guide for Air Brake Compressors, starting on page 11 of this document, to assist your investigation of the cause(s).

Cylinder Head

Check for cylinder head gasket air leakage.

1. With the engine running, lower air system pressure to 60 psi and apply a soap solution around the cylinder head. Check the gasket between the cylinder head and valve plate assembly and the reed valve/gasket between the valve plate assembly and cylinder block for air leakage.

2. No leakage is permitted. If leakage is detected, replace the compressor or repair the cylinder head using a genuine Bendix maintenance kit available from an authorized Bendix parts outlets.

Inlet, Discharge & Unloader

In order to test the inlet and discharge valves and the unloader piston, it is necessary to have shop air pressure and an assortment of ﬁ ttings. A soap solution is also required.

1. With the engine shut off, drain ALL air pressure from the vehicle.

2. Disconnect the inlet and discharge lines and remove the governor or its line or adapter ﬁ tting.

3. Apply 120-130 psi shop air pressure to the unloader port and soap the inlet port. Leakage at the inlet port should not exceed 50 sccm.

4. Apply 120-130 psi shop air pressure to the discharge port and then apply and release air pressure to the inlet port. Soap the inlet port and note that leakage at the inlet port does not exceed 20 sccm.

If excessive leakage is noted in tests 3 or 4, replace or repair the compressor using genuine Bendix® replacements or maintenance kits available from any authorized Bendix parts outlet.

While it is possible to test for inlet, discharge, and unloader piston leakage, it may not be practical to do so. Inlet and discharge valve leakage can generally be detected by longer compressor build-up and recovery times. Compare current compressor build-up times with the last several recorded times. Make certain to test for air system leakage, as described above, before making a determination that compressor performance has been lost.

Unloader leakage is exhibited by excessive compressor cycling between the loaded and unloaded condition.

1. With service and supply system leakage below the maximum allowable limits and the vehicle parked, bring system pressure to governor cut-out and allow the engine to idle.

2. The compressor should remain unloaded for a minimum of 5-10 minutes. If compressor cycling occurs more frequently, and service and supply system leakage is within tolerance (including any leakage that may be present at the air dryer exhaust), replace or repair the compressor unloader system using a genuine Bendix maintenance kit available from authorized Bendix parts outlets.

COMPRESSOR REMOVAL & DISASSEMBLY

GENERAL

The following disassembly and assembly procedure is presented for reference purposes and presupposes that a rebuild or repair of the compressor is being undertaken. Several maintenance kits are available. The instructions provided with these parts and kits should be followed in lieu of the instructions presented here.

MAINTENANCE KITS & SERVICE PARTS

Cylinder Head Gasket Kit ........................................5014472

Unloader Kit .............................................................5014473

Governor Adapter Kit ...............................................5008561

Compressor Seal Kit (crankcase) ............................5008559

CAT MD Seal Kit ......................................................5012367

CAT HD Seal Kit ......................................................5012369

Series 60 Seal Kit ....................................................5012371

ST-4 Discharge Safety Valve (7/8"-14 thrd.) ...............801116

ST-4 Discharge Safety Valve (M16-1.5 thrd.) ............800534

All components shown in Figure 10 with a key number are available in kits and/or as individual service parts.

GENERAL SAFETY GUIDELINES WARNING! PLEASE READ AND FOLLOW

THESE INSTRUCTIONS TO A VOID 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. Where speciﬁ cally directed, the parking brakes may have to be released, and/or spring brakes caged, and this will require that the vehicle be prevented from moving by other means for the duration of these tests/procedures.

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 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 be sure to drain the purge reservoir.

5. Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle.

6. Never exceed manufacturer’s 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 components and kits. Replacement hardware, tubing, hose, ﬁ ttings, etc. must be of equivalent size, type and strength as original equipment and be designed speciﬁ cally 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 specifically 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 Automatic T raction Control (A TC), 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.

air dryer system or a dryer reservoir module,

brand replacement parts,

REMOVAL

In many instances it may not be necessary to remove the compressor from the vehicle when installing the various

Cylinder

Head

7 8

Cooling

Plate

Valve Plate

Assembly

Crankcase

Cylinder

Block

End Cover

Crankcase

Cover

Item Qty. Description Item Qty. Description Item Qty Description

1 2 Unloader Cover Cap Screw 61 1 O-Ring 11 22 Head Gasket 21 1 Unloader Cover 71 1 O-Ring 12 12 Inlet Reed Valve/Gasket 31 1 Unloader Cap Gasket 81 1 Unloader Piston 13 13 O-Ring 41 1 Unloader Balance Piston 91 1 O-Ring 14 13 Bottom Cover Gasket 51 1 Spring 10 1 ST-4™ Safety Valve

Notes: 1. Contained in Unloader Kit 5014473

2. Contained in Cylinder Head Gasket Kit 5014472

3. Contained in Seal Kits 5008559, 5008561, 5008557 & 5008558

FIGURE 9 - BENDIX®BA-922® COMPRESSOR EXPLODED VIEW OF SERVICEABLE PARTS

maintenance kits and service parts. The maintenance technician must assess the installation and determine the correct course of action.

These instructions are general and are intended to be a guide. In some cases additional preparations and precautions are necessary. In all cases follow the instructions contained in the vehicle maintenance manual in lieu of the instructions,

1. Block the wheels of the vehicle and drain the air pressure from all the reservoirs in the system.

2. Drain the engine cooling system and the cylinder head of the compressor. Identify and disconnect all air, water and oil lines leading to the compressor.

3. Remove as much road dirt and grease from the exterior of the compressor as possible.

precautions and procedures presented in this manual.

4. Remove the discharge and inlet ﬁ 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 PREP ARA TION 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 ﬂ 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 ﬁ 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.

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 speciﬁ cally necessary, to mark the relationships of the cylinder head, cooling plate, valve plate assembly , crankcase and cylinder block assembly.

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).

REAR END COVER OR END COVER ADAPTER

1. Remove the four end cover cap screws that secure the rear end cover or end cover adapter to the crankcase.

2. Remove the rear end cover or end cover adapter from the crankcase. Remove the o-ring seal (13) from the end cover.

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.

CYLINDER HEAD

1. Remove the discharge safety valve (10) from the cylinder head.

2. To restrain the spring force exerted by balance piston spring (5), hold the unloader cover (2) in place while removing the two unloader cover cap screws (1). Carefully release the hold on the unloader cover until the spring force is relaxed, then remove the unloader cover (2).

3. Remove the unloader cover gasket (3).

4. Remove the balance piston (4) and its spring (5) from the cylinder head.

5. Remove the six hex head bolts and washers from the cylinder head.

CLEANING OF PARTS

GENERAL

All parts should be cleaned in a good commercial grade of solvent and dried prior to inspection.

CYLINDER HEAD

1. Carefully remove all gasket material adhering to the aluminum cylinder head, steel valve plate assembly and cast iron cylinder block. Make certain not to deeply scratch or mar the gasket surfaces. Pay particular attention to the gasket surfaces of the aluminum head.

2. Remove carbon deposits from the discharge and inlet cavities of the cylinder head and valve plate assembly . They must be open and clear in both assemblies. Make certain not to damage the aluminum head.

3. Remove rust and scale from the cooling cavities and passages in the head and valve plate assembly and use shop air to clear debris from the passages.

4. Check the threads in all cylinder head ports for galling. Minor chasing is permitted.

5. Make certain the unloader vent passage under the unloader cover (2) in the head is open and free of debris.

INSPECTION OF PARTS

CYLINDER HEAD & VALVE PLATE

1. Carefully inspect the cylinder head gasket surfaces for deep gouges and nicks. If detected, the compressor must be replaced.

2. Carefully inspect the valve plate assembly gasket surfaces for deep gouges and nicks. Pay particular attention to the metal gasket surface. A metal gasket (12) is used between the valve plate assembly and the cylinder block. This surface must be smooth and free of all but the most minor scratching. If excessive marring or gouging is detected, the compressor must be replaced.

3. Inspect the cylinder head for cracks or damage. With the cylinder head and head gasket secured to the valve plate assembly, apply shop air pressure to one of the coolant ports with all others plugged, and check for leakage by applying a soap solution to the exterior of the head. If leakage is detected in the cylinder head casting, replace the compressor.

END COVER OR END COVER ADAPTER

Check for cracks and external damage. Check the crankshaft main bearing surface in the end cover or end cover adapter, check for excessive wear and ﬂ at spots and replace the end cover if necessary. Check for galling of the oil port threads and replace the end cover or end cover adapter if necessary. Minor thread chasing is permitted but do not “recut” the threads if they are badly damaged.

CYLINDER BLOCK

1. Check the cylinder head gasket surface on the cylinder block for nicks, gouges, and marring. A metal gasket is used to seal the cylinder head to the cylinder block. This surface must be smooth and free of all but the most minor scratching. If excessive marring or gouging is detected, the compressor must be replaced.

DISCHARGE LINE

1. Inspect the discharge line for kinks, damage, or carbon deposits. Replace as necessary. See the advanced troubleshooting guide for more information.

ASSEMBLY

General Note: All torques speciﬁ ed 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 speciﬁ cations 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.

Example: 12

12 Inch Pounds

= 1 Foot Pound

FOOT POUNDS TO INCH POUNDS To convert foot pounds to inch pounds of torque, multiply foot pounds by 12. Example: 1 Foot Pound

x 12 = 12 Inch Pounds

CRANKCASE COVER

1. Position the crankcase cover gasket (14) on either the

crankcase or crankcase cover and install the crankcase cover on the crankcase using the four cap screws. "Snug" the four cap screws then torque to 62-71 inch pounds (7-8 Nm) using a crossing pattern.

CRANKCASE END COVER OR ADAPTER

1. Install the end cover o-ring (13) on the crankcase end

cover.

2. Orient the crankcase end cover or end cover adapter to

the crankcase using the reference marks made during disassembly. Carefully install the end cover or end cover adapter in the crankcase making certain not to damage the crankshaft bearing surface in it.

3. Install the four end cover screws or studs. "Snug" the

screws then tighten to 195 to 213 inch pounds (22-24 Nm) using a crossing pattern.

CYLINDER HEAD

1. Note the position of the protruding alignment pins on the

cylinder block. Install the metal inlet reed valve/gasket (12) over the alignment pins on the cylinder block.

2. Position the valve plate assembly on the cylinder block

so that the alignment pins in the cylinder block ﬁ t into the corresponding holes in the valve plate assembly.

3. Position and install one of the metal gaskets (11) over

the alignment bushings protruding from the valve plate assembly. When properly installed, the outline of the gasket matches the outline of the valve plate.

4. Install the cooling plate over the alignment bushings

protruding from the valve plate assembly . Again, when properly installed, the outline of the cooling plate matches the outline of the valve plate.

5. Position and install the other metal gasket (11) over the

alignment bushings protruding from the cooling plate assembly . The outline of the gasket matches the outline of the cooling plate.

6. Position and install the cylinder head over the alignment

bushings protruding from the cooling plate. Note: The alignment bushings will only ﬁ t into

two of the six cylinder head bolt holes.

7. Install the two center bolts and six hex head cylinder

head bolts and washers and snug them, then tighten evenly to a torque of 265 to 292 inch pounds (30-33 Nm) using the pattern shown in Figure 9.

8. Install the unloader piston (7) with its pre-installed

o-rings (6, 8, 9) in the cylinder head making certain not to damage them in the process.

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).

INSTALLING THE COMPRESSOR

1. If the compressor was removed for replacement, install the drive components. T orque 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 ﬂ 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 ﬁ 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 Speciﬁ cations for various ﬁ tting sizes and types of thread on page 11 of this manual.

5. Inspect all air, oil, and coolant lines and ﬁ 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 brieﬂ y to be sure oil is ﬂ owing freely through the supply line.

7. Before returning the vehicle to service, perform the Operation and Leakage Tests speciﬁ ed 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.

TESTING REBUILT COMPRESSOR

In order to properly test a compressor under operating conditions, a test rack for correct mounting, cooling, lubricating, and driving the compressor is necessary . Such tests are not compulsory if the unit has been carefully rebuilt by an experienced person. A compressor efﬁ ciency, or build-up test, can be run with realite ease. An engine

5, 11

1, 15

7,13

Sequence Torque (Nm)

1 . . . . . . . . . . . 13

2 . . . . . . . . . . . 13

3 . . . . . . . . . . . 20

4 . . . . . . . . . . . 20

5 . . . . . . . . . . . 20

6 . . . . . . . . . . . 20

7 . . . . . . . . . . . 20

8 . . . . . . . . . . . 20

FIGURE 10 - BENDIX® BA-922® COMPRESSOR HEAD BOLT TORQUE SEQUENCE

3, 9

8, 14

2, 16

4, 10

6, 12

Sequence Torque (Nm)

9 . . . . . . . . . . . 32

10 . . . . . . . . . . 32

11 . . . . . . . . . . 32

12 . . . . . . . . . . 32

13 . . . . . . . . . . 32

14 . . . . . . . . . . 32

15 . . . . . . . . . . 13

16 . . . . . . . . . . 13

lubricated compressor must be connected to an oil supply line of at least 15 psi pressure during the test and an oil return line must be installed to keep the crankcase drained. Connect to the compressor discharge port, a reservoir with a volume of 1500 cubic inches, including the volume of the connecting line. With the compressor operating at 2100 RPM, the time required to raise the reservoir(s) pressure from 85 psi to 100 psi should not exceed 5 seconds. During this test, the compressor should be checked for gasket leakage and noisy operation, as well as unloader operation and leakage. If the compressor functions as indicated, reinstall on the vehicle connecting all lines as marked in the disassembly procedure.

BENDIX® BA-922® COMPRESSOR SPECIFICA TIONS

Typical weight ................................................................. 60 lbs.

Number of cylinders ................................................................ 2

Bore Diameter ...................................... 3.622 in. (92.005 mm)

Stroke ................................................... 2.125 in. (53.970 mm)

Calculated displacement at 1250 RPM ..................... 31.7 CFM

Flow Capacity @ 1800 RPM & 120 PSI ......................25.2 CFM

Flow Capacity @ 3000 RPM & 120 PSI ......................38.4 CFM

Maximum recommended RPM ................................ 3000 RPM

Minimum coolant ﬂ ow maximum RPM ............... 2.0 Gals./Min.

Approximate horsepower required:

Loaded 1800 RPM at 120 PSIG ................................... 8.73 HP

Unloaded 1800 RPM .................................................... 1.96 HP

Maximum inlet air temperature ........................................ 170°F

Maximum discharge air temperature ............................... 350°F

Minimum oil pressure required ........................................ 15 PSI

Minimum oil-supply line size ...................................... 3/16" I.D.

Minimum unloader-line size ....................................... 3/16" I.D.

Minimum Governor Cut-out Pressure .............................120 PSI

TORQUE SPECIFICATIONS

Assembly Torques in inch pounds (in. Ibs.)

M8x1.25-6g Cylinder Head ..........265-292 In. Lbs. (30-33 Nm)

M5x0.75-6g Unloader Cap ...................62-71 In. Lbs. (7-8 Nm)

M8x1.25-6g Governor Adapter ....195-213 In. Lbs. (22-24 Nm)

M8x1.25-6g Rear End Cover........195-213 In. Lbs. (22-24 Nm)

M6x1.00-6g Crankcase Cover ........... 62-71 In. Lbs. (7-8 Nm)

M20x2.50-6g Crankshaft Nut 1858-2567 In. Lbs. (210-290 Nm)

Inlet Port Fittings

1 3/16"-12 UN-2B ..........................575-637 In. Lbs. (65-72 Nm)

M27 x 2.0 .......................................575-637 In. Lbs. (65-72 Nm)

Discharge Port Fittings

7/8"-14 UNF-2B .............................460-504 In. Lbs. (52-57 Nm)

M22 x 1.5 .......................................195-213 In. Lbs. (22-24 Nm)

Water Port Fittings

3/4"-16 UNF-2B .............................319-245 In. Lbs. (36-39 Nm)

M18 x 1.5-6g..................................230-257 In. Lbs. (26-29 Nm)

Unloader Port Fittings

1/8"-27 NPT ..............................................................2 - 3 TFFT

M10 x 1.5-6g..................................120-145 In. Lbs. (14-16 Nm)

Safety Valve Port

M16 x 1.5 .......................................230-257 In. Lbs. (26-29 Nm)

3/4"-16 UNF-2B .............................319-345 In. Lbs. (36-39 Nm)

7/8"-14 UNF-2A .............................319-345 In. Lbs. (36-39 Nm)

1/2"-14 NPT ..............................................................2 - 3 TFFT

Oil Port

7/16"-20 UNF ....................................97-115 In. Lbs. (11-13 Nm)

M12 x 1.5-6g..................................142-159 In. Lbs. (16-18 Nm)

Note: TFFT = Turns From Finger Tight

Advanced Troubleshooting Guide for Air Brake Compressors

INDEX

Symptom Page Number

Air

Air brake charging system:

Slow build (9.0) .....................................19 - 20

Doesn’t build air (10.0) .................................21

Air dryer:

Doesn’t purge (14.0) ....................................22

Safety valve releases air (12.0) ...................22

Compressor:

Constantly cycles (15.0) ..............................22

Leaks air (16.0) ............................................23

Safety valve releases air (11.0) ...................21

Noisy (18.0) ................................................23

Reservoir:

Safety valve releases air (13.0) ...................22

Test Procedures

(1) Oil Leakage at Head Gasket ........24

(2) System Leakage ..........................24

(3) Compressor Discharge and

Air Dryer Inlet Temperature ........... 24

(4) Governor Malfunction ................... 24

(5) Governor Control Line .................. 25

(6) Compressor Unloader .................. 25

BASIC Test Information ................26-28

Symptom Page Number

Coolant

Compressor leaks coolant (17.0).......................23

Engine

Oil consumption (6.0) ....................................... 19

Oil

Oil Test Card results (1.0) .................................. 14

Oil is present:

On the outside of the compressor (2.0) ....... 15

At the air dryer purge/exhaust

or surrounding area (3.0) ......................... 15

In the supply reservoir (4.0) ..................16 - 18

At the valves (5.0) ........................................18

At air dryer cartridge (7.0) ............................19

In the ping tank or compressor

discharge aftercooler (8.0)....................... 19

Maintenance & Usage Guidelines

Maintenance Schedule and

Usage Guidelines (Table A) .......13

Introduction to the Air Brake Charging System

Powered by the vehicle engine, the air compressor builds the air pressure for the air brake system. The air compressor is typically cooled by the engine coolant system and lubricated by the engine oil supply.

The compressor's unloader mechanism and governor (along with a synchro valve for the Bendix

DuraFlo 596

™

air compressor) control the brake system air pressure between a preset maximum and minimum pressure level by monitoring the pressure in the service (or “supply”) reservoir. When the air pressure becomes greater than that of the preset “cut-out”, the governor controls the unloader mechanism of the compressor to stop the compressor from building air and also causes the air dryer to purge. As the service reservoir air pressure drops to the “cut-in” setting of the governor, the governor returns the compressor back to building air and the air dryer to air drying mode.

As the atmospheric air is compressed, all the water vapor originally in the air is carried along into the air system, as well as a small amount of the lubricating oil as vapor.

The duty cycle is the ratio of time the compressor spends building air to the 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. The discharge line allows the air, water-vapor and oil-vapor mixture to cool between the compressor and air dryer. The typical size of a vehicle's discharge line, (see

column 2 of Table A on page 13) assumes a compressor with a normal (less than 25%) duty cycle, operating in a temperate climate. See Bendix and/or other air dryer manufacturer guidelines as needed.

When the temperature of the compressed air that enters the air dryer is within the normal range, the air dryer can remove most of the charging system oil. If the temperature of the compressed air is above the normal range, oil as oil-vapor is able to pass through the air dryer and into the air system. Larger diameter discharge lines and/or longer discharge line lengths can help reduce the temperature.

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 freeze-ups, see Bendix Bulletins TCH-008-021 and TCH-008-022 (see pages 30-32). Shorter discharge line lengths or insulation may be required in cold climates.

The air dryer contains a ﬁ lter that collects oil droplets, and a desiccant bed that removes almost all of the remaining water vapor. The compressed air is then passed to the air brake service (supply) reservoir. The oil droplets and the water collected are automatically purged when the governor reaches its “cut-out” setting.

For vehicles with accessories that are sensitive to small amounts of oil, we recommended installation of a Bendix

PuraGuard® system ﬁ lter, designed to minimize the amount of oil present.

Discharge Line

Compressor

Optional “Ping” Tank

(Governor plus Synchro valve for the Bendix

Compressor)

Air Dryer

Governor

DuraFlo 596

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 PuraGuardQC Oil Coalescing Filter

™

Service Reservoir

(Supply Reservoir)

Reservoir Drain

™

Table A: Maintenance Schedule and Usage Guidelines

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

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 Replacement1 Schedule2 Drain Interval

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

less

e.g. Line haul single trailer

with air suspension, RV

school bus.

less

High Air Use

Compressor with up to 25% duty cycle

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.

Compressor with up to 25% duty cycle

less

e.g. City transit bus, refuse,

bulk unloaders, low boys,

urban region coach, central

tire inﬂ ation.

less

Column 1

(See footnote 7)

1/2 in.

For oil carry-over

control4suggested

5/8 in. 9 ft.

550 air compressor

For oil carry-over

control4suggested

Tu-Flo

air compressor

BA-921

Bendix

750 air compressor

5/8 in. 12 ft.

Bendix

1/2 in.

For oil carry-over

control4suggested

5/8 in. 15 ft.

Tu-Flo

Bendix

air compressor

™

3/4 in.

, or DuraFlo 596

Column 2 Column 3 Column 4 Column 5

I.D.

Length

6 ft.

BASIC test

acceptable

upgrades:

9 ft.1/2 in.

Every 3

Years

Recom-

mended

Every

Month -

Max of

range:

3 oil units

per month.

appendix

every 90

days

upgrades:

For the

BASIC

Test Kit:

Order

Bendix

5013711

12 ft.

Every 2

Years

upgrades:

BASIC test

acceptable

range:

Every

Month

5 oil units

per month.

appendix

12 ft.

Every

Year

See

P/N

See

BA-922

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. 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 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: To 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.

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 recommended every 250,000 miles.

Tu-Flo® 550 and 750 compressors, unloader service is

Air Brake Charging System Troubleshooting

How to use this guide: Find the symptom(s) that you see, then move to the right to ﬁ 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

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.

Look for:

Normal - Charging system is working within normal range.

Check - Charging system needs further investigation.

5. Following the vehicle manufacturer’s recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle.

6. Never exceed manufacturer’s 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.

9. Components with stripped threads or damaged parts should be replaced rather than repaired. Do not attempt repairs requiring machining or welding unless speciﬁ cally 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 Automatic Traction Control (A TC), the A TC 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.

brand replacement parts,

Symptom: What it may indicate: What you should do:

1.0 Oil Test Card Results

Not a valid test.



Bendix

BASIC Test

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 deﬁ nitive 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.)

BASIC test should be the



Symptom: What it may indicate: What you should do:

2.0 Oil on the Outside of the Compressor

2.1 Oil leaking at compressor / engine connections:

2.2 Oil leaking from compressor:

Engine and/or other accessories leaking onto compressor.

(a)Leak at the front or rear (fuel

pump, etc.) mounting ﬂ ange.

(b) Leak at air inlet ﬁ tting.

(d) Loose/broken oil line ﬁ ttings.

(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.)

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 ﬁ tting gasket. Inspect inlet hose

and replace as necessary.

Replace gasket or ﬁ tting as necessary to

ensure good seal.

Inspect and repair as necessary.

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)



3.0 Oil at air dryer purge/exhaust or surrounding area

Head gaskets and rear



ﬂ ange gasket locations.

(c)

Air brake charging system functioning normally.

(c)

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.

® ®

Symptom: What it may indicate: What you should do:

4.0 Oil in Supply or Service Reservoir (air dryer installed)

(If a maintained Bendix PuraGuard® system ﬁ lter or Bendix PuraGuard QC coalescing ﬁ lter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a T ech Team

member.)

See Table A, on page 13, for maintenance schedule information.

™

oil

Maintenance

(a)If air brake charging system mainte-

nance 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.

(a)

Drain all air tanks (reservoirs) into the Bendix

(Bendix kit P/N 5013711).

cup.

BASIC test

Drain all air tanks and check vehicle at next

service interval using the Bendix

BASIC test. See T able A on page 13, column 3 and 4, for recommended service schedule.

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 ﬁ lter.

If outside the normal range go to Symp-

tom 4.0(c).

Also see the Table A on page 13, column

3 for recommended air dryer cartridge replacement schedule.

Duty cycle too high

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 ﬁ 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).

Symptom: What it may indicate: What you should do:

4.0 Oil in Supply or Service Reservoir* (air dryer installed) (continued)

(e)

(g)

Testing the temperature at the discharge ﬁ tting.

(g)

Kinked discharge line shown.

Temperature

(e) Air compressor discharge and/or

air dryer inlet temperature too high.

(f) Insufﬁ cient coolant ﬂ ow.

(f)

Inspecting the coolant hoses.

(g) Restricted discharge line.

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 ﬁ 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 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 (Appendix B). Shorter discharge line lengths or insulation may be required in cold climates.

(h)

Other

(h) Restricted air inlet (not enough air

to compressor).

Check compressor air inlet line for restric-

tions, 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

Partly collapsed inlet line shown.

*If a maintained Bendix ﬁ lter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.

PuraGuard® system ﬁ lter or Bendix® PuraGuard QC™ oil coalescing

necessary (if possible, check the air ﬁ lter usage indicator).

Symptom: What it may indicate: What you should do:

4.0 Oil in Supply or Service Reservoir* (air dryer installed)

Other (cont.)

(i) Poorly filtered inlet air (poor air

quality to compressor).

(continued)

(j) Governor malfunction or setting. (k) Compressor malfunction.

Crankcase Flooding Consider installing a compressor bottom drain kit

(where available) in cases of chronic oil passing where all other operating conditions have been investigated. Bendix compressors are designed to have a 'dry' sump and the presence of excess oil in the crankcase can lead to oil carryover.

Check for leaking, damaged or defective

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.

Inspect the engine air cleaner.

Go to Test 4 on page 25. If you found excessive oil present in the

service reservoir in step 4.0 (b) above and you did not ﬁ nd any issues in steps 4.0 (c) through 4.0 (j) above, the compressor may be passing oil.

Replace compressor. If still under warranty ,

follow normal warranty process. Note: After replacing a compressor, residual oil may take a considerable period of time to be ﬂ ushed from the air brake system.

*If a maintained Bendix ﬁ lter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.

5.0 Oil present at valves (e.g. at

PuraGuard® system ﬁ lter or Bendix® PuraGuard QC™ oil coalescing

Air brake system valves are required to tolerate a light coating of oil.

A small amount of oil does not affect SAE

J2024** compliant valves.

exhaust, or seen during servicing).

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 Bendix® BASIC test cup (see also column 5 of Table A on page 13). Return the vehicle to service.

For oil-sensitive systems, see page 12.

** SAE J2024 outlines tests all air brake system pneumatic

components need to be able to pass, including minimum levels of tolerance to contamination.

Genuine Bendix valves are all SAE J2024 compliant.

Symptom: What it may indicate: What you should do:

6.0 Excessive oil consumption in engine.

7.0 Oil present at air dryer cartridge during maintenance.

8.0 Oil in ping tank or compressor discharge aftercooler.

9.0 Air brake charging system seems slow to build pressure.

A problem with engine or other engine accessory.

The engine service manual has more information.

Air brake charging system is functioning normally.

Oil shown leaking from an air dryer cartridge.

Air brake charging system is functioning normally.

(a) Air brake charging system

functioning normally.

See engine service manual.

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 by the BASIC Test (see also column 5 of Table A on page 13). Replace the air dryer cartridge as needed and return the vehicle to service.

Follow vehicle O.E. maintenance

recommendation for these components.

Using dash gauges, verify that the

compressor builds air system pressure from 85-100 psi in 40 seconds or less with engine at full governed rpm. Return the

vehicle to service. (b) Air brake system leakage. (c) Compressor may be undersized for

the application.

(d) Compressor unloader mechanism

malfunction.

(e) Damaged compressor head

gasket.

Go to Test 2 on page 24. See T able A, column 1, on page 13 for some

typical compressor applications. If the

compressor is "too small" for the vehicle's

role, for example, where a vehicle's use has

changed, then upgrade the compressor.

Note: The costs incurred (e.g. installing

a larger capacity compressor, etc.) are

not covered under original compressor

warranty.

Go to Test 6 on page 25.

An air leak at the head gasket may indi-

cate 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 re-

use the safety valve without testing. See

Symptom 12.0(a).

Symptom: What it may indicate: What you should do:

9.0 Air brake

(f) Restricted discharge line.

charging system seems slow to build pressure. (continued)

(f)

Dash gauges.

Kinked discharge line shown.

Engine Oil Quality

Inadequate oil change intervals, the formulation of the oil and/or the quality of oil ﬁ lter used can all lead to poor oil quality . These can increase the rate at which carbon builds up in the discharge line. Bendix recommends oil soot (solids) be maintained at less than 3%.

If discharge line is restricted:

 By more than 1/16" carbon build up,

replace the discharge line (see Table A, column 2, on page 13 for recommended size) and go to Test 3 on page 24.  By other restrictions (e.g. kinks). Replace the discharge line. See Table A, column 2, on page 13 for recommended size. Retest for air build. Return vehicle to service or, if problem persists, go to 9.0(a).

The discharge line must maintain a

(g)

Partly collapsed inlet line shown.

(g) Restricted air inlet (not enough air

to compressor).

(h)Poorly filtered inlet air (poor air

quality to compressor).

(i) Compressor malfunction.

Check compressor air inlet line for restric-

tions, brittleness, soft or sagging hose conditions etc. Repair as necessary. Refer to vehicle manufacturer’s guidelines for inlet line size.

Check the engine air ﬁ lter and service if

necessary (if possible, check the air ﬁ lter usage indicator).

Check for leaking, damaged or defective

Replace the compressor only after making

certain that none of the preceding conditions,

9.0 (a) through 9.0 (h), exist.

Symptom: What it may indicate: What you should do:

10.0 Air charging system doesn’t build air.

* Note: For the Bendix® DuraFlo 596™air compressor, not only the governor, but also the SV-1™ synchro valve used would need to be tested. See Bulletin TCH-001-048.

11.0 Compressor safety valve releases air (Compressor builds too much air).



(a) Governor malfunction*. (b) Restricted discharge line. (c)Air dryer heater malfunction:

exhaust port frozen open.

(d) Compressor malfunction.

(a) Restricted discharge line.

Damaged discharge line shown.

Go to Test 4 on page 25. See 9.0(f). Replace air dryer heater.

Replace the compressor only after making

certain the preceding conditions do not exist.

If discharge line is restricted:

 By more than 1/16" carbon build up,

The discharge line must maintain a

(b)Downstream air brake system check

valves or lines may be blocked or damaged.

(d) Compressor safety valve

malfunction.

(e) Compressor unloader mechanism

malfunction.

(f) Governor malfunction.

Inspect air lines and verify check valves are

operating properly.

Ensure discharge line is installed into the

inlet of the air dryer and delivery is routed to the service reservoir.

Verify relief pressure is 250 psi. Replace if

defective.

Go to Test 6 on page 25.

Go to Test 4 on page 25.

Symptom: What it may indicate: What you should do:

12.0 Air dryer safety valve releases air.

Air dryer safety valve





Technician removes governor.

13.0 Reservoir safety valve releases air

(a) Restriction between air dryer and

reservoir.

(b) Air dryer safety valve

malfunction.

performed.

(d) Air dryer malfunction.

(e)Improper governor control line

installation to the reservoir.

(f) Governor malfunction.

(a) Reservoir safety valve

malfunction.

(b) Governor malfunction.

Inspect delivery lines to reservoir for restric-

tions and repair as needed.

Verify relief pressure is at vehicle or

component manufacturer speciﬁ cations. 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 speciﬁ cations (typically 150 psi). Replace if defective.

Go to Test 4 on page 25.

14.0 Air dryer doesn’t purge. (Never hear exhaust from air dryer.)

15.0 Compressor constantly cycles (compressor remains unloaded for a very short time.)

malfunction.

(a) Air dryer malfunction.

(b) Governor malfunction. (c) Air brake system leakage. (d)Improper governor control line

installation to the reservoir.

(a)Air brake charging system

maintenance not performed.

(b) Compressor unloader mechanism

malfunction.

check valve malfunction.

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 re-

duced 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.

(d) Air brake system leakage.

Go to Test 2 on page 24.

Symptom: What it may indicate: What you should do:

16.0 Compressor leaks air

Testing for leaks with soap solution.

17.0 Compressor leaks coolant

(a) Compressor leaks air at connections

or ports.

(b) Compressor unloader mechanism

malfunction.

gasket(s).

Head

gaskets



locations



(a)Improperly installed plugs or coolant

line ﬁ ttings.

Check for leaking, damaged or defective

compressor ﬁ 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).

Inspect for loose or over-torqued ﬁ ttings.

Reseal and tighten loose ﬁ ttings and plugs as necessary. If overtorqued ﬁ ttings and plugs have cracked ports in the head, replace the compressor.

18.0 Noisy compressor (Multi-cylinder compressors only)

This guide attempts to cover most compressor system problems. Here are some rare sources of problems not covered in this guide:

• Turbocharger leakage. Lubricating oil

from leaking turbocharger seals can enter the air compressor intake and give misleading symptoms.

(b) Damaged compressor head

gasket.

(a) Damaged compressor.

Other Miscellaneous Areas to Consider

• Where a compressor does not have

a safety valve installed, if a partial or complete discharge line blockage has occurred, damage can occur to the connecting rod bearings. Damage of this kind may not be detected and could lead to compressor problems at a later date.

An air leak at the head gasket may indicate

a downstream restriction such as a freezeup 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 re-use the safety valve without testing. See Symptom

12.0(a).

If casting porosity is detected, replace the

compressor.

Replace the compressor.

Tests

Test 1: Excessive Oil Leakage at the

Head Gasket

Exterior leaks at the head gasket are not a sign that oil is being passed into the air charging system. Oil weepage at the head gasket does not prevent the compressor from building air.

Observe the amount of weepage from the head gasket. If the oil is only around the cylinder head area, it is acceptable (return the vehicle

to service), but, if the oil weepage extends down to the nameplate area of the compressor, the gasket can be replaced.

Test 2: Air Brake System and Accessory Leakage

Look

for

Weepage

Inspect for air leaks when working on a vehicle and repair them promptly. Park the vehicle on level ground and chock wheels. Build system pressure to governor cut-out and allow the pressure to stabilize for one minute. Step 1: Observe the dash gauges for two additional minutes without the service brakes applied. Step 2: Apply the service brakes and allow the pressure to stabilize. Continue holding for two minutes (you may use a block of wood to hold the

Test 3: Air Compressor Discharge

Temperature and Air Dryer Inlet

Temperature*

Caution: The temperatures used in this test are not normal vehicle conditions. Above normal temperatures can cause oil (as vapor) to pass through the air dryer into the air brake system.

This test is run with the engine at normal operating temperature, with engine at max. rpm. If available, a dyno may be used.

1. Allow the compressor to build the air system pressure to governor cut-in.

2. Pump the brakes to bring the dash gauge pressure to 90 psi.

3. Allow the compressor to build pressure from 95 to 105 psi gauge pressure and maintain this pressure range by cycling the brakes for

ﬁ ve (5) minutes.

Discharge Line

pedal in position.) Observe the dash gauges. If you see any noticeable decrease of the dash air gauge readings (i.e. more than 4 psi, plus two psi for each additional trailer) during either two minute test, repair the leaks and repeat this test to conﬁ rm that they have been repaired. Air leaks can also be found in the charging system, parking brakes, and/or other components - inspect and repair as necessary.

(* Note that only vehicles that have passed Test 2 would be candidates for this test.)

4. Then, while maintaining max rpm and pressure range, measure and record the surface temperature of the ﬁ ttings:

 at the compressor discharge port. (T1).  at the air dryer inlet ﬁ tting. (T2).

Use a touch probe thermocouple for measuring

the temperature.

5. See table below.

6. Retest before returning the vehicle to service.

T1 T2

Compressor Air Dryer Discharge Inlet Fitting Fitting

under under Temperatures are within 360°F 200°F normal range for this test, check other symptoms. Go to 4.0 (h).

under over This could indicate a discharge 360°F 200°F line problem (e.g. restriction). Call 1-800-AIR-BRAKE (1-800-247-2725) and speak with our Tech Team.

over __ Compressor is running hot. 360°F Check coolant 4(f) and/or discharge line 4(g).

Action

Tests (continued)

Test 4: Governor Malfunction

1. Inspect control lines to and from the governor for restrictions (e.g. collapsed or kinked). Repair as necessary.

2. Using a calibrated external gauge in the

Test 5: Governor Control Line

supply reservoir, service reservoir , or reservoir port of the D-2 cut-out pressures are within vehicle OEM speciﬁ cation.

3. If the governor is malfunctioning, replace it.

governor, verify cut-in and

1. Ensure that the governor control line from the reservoir is located at or near the top of the reservoir. (This line, if located near the bottom of the reservoir, can become blocked or restricted by the reservoir contents e.g. water or ice.)

Test 6: Compressor Unloader Leakage

Bendix® Compressors: Park vehicle, chock

wheels, and follow all standard safety procedures. Remove the governor and install a ﬁ tting to the unloader port. Add a section of air hose (min 1 ft long for a 1/2" diameter line) and a gauge to the ﬁ tting followed by a shut-off valve and an air source (shop air or small air tank). Open the

2. Perform proper reservoir drain intervals and air dryer cartridge maintenance per Maintenance Schedule and Usage Guidelines (Table A on page 13).

3. Return the vehicle to service.

shut off and charge the unloader port by allowing air pressure to enter the hose and unload the compressor. Shut off the air supply and observe the gauge. A steady reading indicates no leakage at the unloader port, but a falling reading shows that the unloader mechanism is leaking and needs to be serviced.

Appendix A: Information about the BASIC Test Kit (Bendix P/N 5013711)

Service writer records info - including the number of days since all air tanks were ills out symptom

drained - and f

checklist. Technicianinspects items.

START BASIC TEST

Park vehicle on ground.LEVEL

Chock wheels, drain air from system.

days

Bendix® Air System Inspection Cup

(BASIC) Test Information

Drain contents of air

tanks into

YES, this is a high air use vehicle.

Find the point on the label

where the number of oil units

High

meets the number of days*

since the vehicle's air tanks

were last drained.

Is the

point above

the HIGH Air Use

line on the

cup?

High

YES

ALL

™

BASIC cup

Is there less than one unit of liquid?

there more

than one unit of:

• water, or

• cloudy emulsion

mixture?

NO, only oil.

Is this a

transit vehicle, bulk

unloader, or has more

than 5 axles?

Low

High

Low

YES

NO, this is a low air

use vehicle.

Find the point on the label

where the number of oil units

meets the number of days* since the vehicle's air tanks

were last drained.

Is the

point above

the LOW Air Use

line on the

cup?

YES

Vehicle OK.

Return vehicle to

service.

Cloudy emulsion mixture

Is this vehicle

being re-tested? (after

water, etc. was found

last time?)

Low

YES

Go to the

Advanced

Troubleshooting

Guide to find reason(s) for

presence of water

END TEST

Change air dryer

Test for air

leakage

END TEST

cartridge**

Use Test 2: Air Leakage

Re-test with the

™

BASIC Test after

30 days***

Test for air

leakage

Compressor

Use Test 2: Air Leakage

Does

the vehicle have

excessive air

leakage?

Was

the number of

days since last

draining

known?

Replace the Compressor. If under warranty, follow standard procedures.

If, after a compressor was already replaced, the vehicle fails the BASIC test again, do not replace the compressor**** - use the Advanced Troubleshooting Guide to investigate the cause(s).

END TEST

YES

Repair leaks and

return vehicle to

service

NO (did not know

when last

drained)

YES, number of days was known (30 - 90 days)

Re-test with the

BASIC Test after

™

30 days***

END TEST

Vehicle OK.

Return vehicle to

service.

END TEST

* If the number of days since the air tanks were drained is unknown

- use the 30 day line. ** 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.

*** T o 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-008-021 and TCH-008-022 (included on pages 30-32 of this document).

****Note: After replacing a compressor, residual oil may take a considerable period of time to be ﬂ ushed from the air brake system.

Appendix A continued: Information about the BASIC Test Kit (Bendix P/N 5013711)

Filling in the Checklist for the Bendix

Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer.

The Service Writer ﬁ lls out these ﬁ elds with information gained from the customer

Number of Days Since Air Tanks Were Last Drained: ________ Date: ___________Vehicle #: ____________ Engine SN __________________________ Vehicle Used for: _______________Typical Load:________ (lbs.) No. of Axles: ____ (tractor) ____ (trailer) No. of Lift Axles: ____ Technician’s Name: ____________________

Air System Inspection Cup (BASIC) T est

Customer’s Have you conﬁ rmed complaint? (Please check all that apply)

“Relay valve leaks oil /  malfunctions” no yes*

Checklist for Technician

The Service Writer also checks off any complaints that the customer makes to help the T echnician in investigating.

“Dash valve leaks oil / malfunctions”no yes*

“Air dryer leaks oil” no yes* “Governor malfunction”no yes* “Oil in gladhands” no yes*

how much oil did you ﬁ nd? ________________________________ “Oil on ground or vehicle exterior” no yes* amount described: ______________________________________ “Short air dryer cartridge life” replaces every: ______________  miles,  kms, or  months  “Oil in air tanks” amount described:_______________________

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 checks boxes for any of the complaints that can be conﬁ rmed.

Note: A conﬁ rmed complaint

above does NOT mean that the compressor must be replaced. The full BASIC test below will investigate the facts.

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.

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 vehicle’s air dryer cartridge

- see Footnote 1, (b) Conduct the 4 minute leakage test (Step D),

Units

again after 30 days - see Footnote 2.

STOP + CK.

Oil

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.

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-008-021 and TCH-008-022 (included in Appendix B of the advanced troubleshooting guide).

For an accurate test, the contents of all the air tanks on the vehicle should be used.

Appendix A continued: Information about the BASIC Test Kit (Bendix P/N 5013711)

Filling in the Checklist for the Bendix

Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer.

Air System Inspection Cup (BASIC) T est

STEP C - How to Use the BASIC Test

The T echnician uses the chart (label) on the BASIC test cup to help decide the action to take, based on the amount of oil found. Use the lower acceptance line for low air use vehicles, and upper line for high air use vehicles (from Step A).

BASIC Test Example

1. Record days since air

tanks were last drained.

_________ days



If number of days is:

30-60 days (high air

use) or

30-90 days (low air

use)



Otherwise . . .



(if the number of days is unknown, or outside the

limits above)

2. Record amount

_________ units

if oil level is at or below

acceptance line for number

of days

if oil level is above

acceptance line for number

of days 

if oil level is at or below

30-day acceptance line 

if oil level is above 30-day

acceptance line 

Acceptance

An oil level of 4 units in a sixty-day period is within the acceptance area (at or below the line) for both low and high air use vehicles. Return the vehicle to service.

The Technician looks for the point where the number of days since the air tanks were drained meets the oil level. If it is at or below the (low or high use) acceptance line, the vehicle has passed the test. If the point is above the line then go to the leakage test.

STEP D - Air Brake System Leakage Test

Park the vehicle on level ground and chock wheels. Build system pressure to governor cut-out and allow the pressure to stabilize for one minute.

1: Observe the dash gauges for two additional minutes without the service brakes applied. 2: Apply service brakes for two minutes (allow pressure to stabilize) and observe the dash

gauges. If you see any noticeable decrease of the dash air gauge readings, repair leaks. Repeat this test to conﬁ rm that air leaks have been repaired and return vehicle to service. Please repeat BASIC test at next service interval. Note: Air leaks can also be found in the charging system, parking brakes, and/or other components - inspect and repair as necessary.

Sixty days since last air

tank draining

of oil found:



Lines

Decision point

3. Action to take



System OK. Return to service.

Go to Step D

System OK. Return to service. Stop inspection.

Test again after 30 days. See Footnote 2.

Oil

Level

STOP TEST

STOP + CK.

Air leakage is the number one cause of compressors having to pump excessive amounts of air, in turn run too hot and pass oil vapor along into the system. Here the Technician conducts a four-minute test to see if leakage is a problem with the vehicle being tested.

If no air leakage was detected, and if you are conducting

this test after completing Step C, go to Step E.

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: 3-5-2010 Cancels PRO-08-21 dated 2-6-2008 Page: 1 of 2

Subject: Air Brake System - Cold Weather Operation Tips

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Appendix B: Continued

Bulletin No.: TCH-008-021 Effective Date: 3/5/2010 Page: 2 of 2

System Leakage

Check the air brake system for excessive air leakage using the Bendix “Dual System Air Brake Test and Check List” (BW1279). Excessive system leakage causes the compressor to “pump” more air and also reduce the life of the air dryer desiccant cartridge.

Reservoir Draining (System without an Air Dryer)

Routine reservoir draining is the most basic step in reducing the possibility of freeze-up. All reservoirs in a brake system can accumulate water and other contamination and must be drained! The best practice is to drain all reservoirs daily if the air brake system does not include an air dryer. When draining reservoirs; turn the ENGINE OFF and drain ALL AIR from the reservoir, better still, open the drain cocks on all reservoirs and leave them open over night to assure all contamination is drained (reference Service Data Sheet SD-04-400 for Bendix Reservoirs). If automatic drain valves are installed, check their operation before the weather turns cold (reference Service Data Sheet SD-03-2501 for Bendix while the need for daily reservoir draining is eliminated through the use of an automatic drain valve, periodic manual draining is still required.

Reservoir Draining (System with an Air Dryer)

Daily reservoir draining should not be performed on systems with an air dryer. This practice will cause the dryer to do excessive work (i.e. build pressure from 0-130 psi instead of the normal 110-130 psi).

Alcohol Evaporator or Injector Systems

Bendix Commercial Vehicle Systems LLC discourages the use of alcohol in the air brake system as a means of preventing system freeze-up in cold temperatures. Studies indicate that using alcohol and alcohol based products sold for this purpose removes the lubrication from the components of the air braking system. In addition, the materials used for the internal seals of the air system components may be adversely impacted by the residue that some anti-freeze additives leave behind. Both are detrimental to air system component life expectancy, causing premature wear. Because of this, Bendix® air system components warranty will be void if analysis shows that alcohol was added to the air brake system.

Alcohol is not an acceptable substitute for having adequate air drying capacity. If the air dryer is maintained in accordance with the manufacturer’s recommended practices and moisture is found to be present in the system reservoirs, more drying capacity is required. Bendix has several viable options including extended purge air dryers, extended purge tandem dryers in parallel with common control, and air dryers arranged to provide continuous  ow as with the Bendix® EverFlow® continuous  ow air dryer module. To address concerns with contaminants in trailer air brake systems, the Bendix® Cyclone DuraDrain™ water separator and the Bendix System-Guard® trailer air dryer are available. Refer to Bendix Technical Bulletin TCH-008-042 “Alcohol in the Air Brake System” for additional information.

Air Dryers

Make certain air brake system leakage is within the limits stated in BW1279. Check the operation and function of the air dryer using the appropriate Service Data Sheet for the air dryer.

DV-2™ Automatic Drain Valves). It should be noted that,

Air Dryer Service Data Sheet

AD-2® air dryer SD-08-2403

air dryer SD-08-2407

AD-4

air dryer SD-08-2412

AD-9

air dryer SD-08-2414

AD-IP

AD-IS

air dryer SD-08-2418

EverFlow® air dryer SD-08-2417

AD-IS

AD-SP

Cyclone DuraDrain

PuraGuard® QC system  lter SD-08-187B

Trailer System-Guard

air dryer SD-08-2415

™

water separator SD-08-2402

air dryer SD-08-2416

Bendix literature is

available to order or

download on Bendix.com

Appendix B: Continued

Technical Bulletin

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 Do’s and Don’ts for prevention and thawing.

Do’s

1. Do maintain freeze prevention devices to prevent road calls. Don’t 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.

Don’ts

1. Do not apply an open ﬂ 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) ﬂ uids into air brake lines or hose couplings (“glad hands”). Some ﬂ 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. Don’t overlook them until they fail and a road call is required.

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BENDIX SD-01-700 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual