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22

A-4

Air Brake Charging System Troubleshooting

1.0  Oil Test Card 

Results

Not a valid 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 BASIC test should be the 

definitive  method  for  judging  excessive 

oil fouling/oil passing.  

(See Appendix A, 

on  page A-16  for  a  flowchart  and  expanded 

explanation of the checklist used when 

conducting the BASIC test.)

Symptom: 

What it may indicate: 

What you should do:  

How to use this guide:

Find the 

symptom(s)

 that you see, then move to the right to 

find 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.

Look for:

Normal - Charging system is working within 

normal range.

Check - Charging system needs further  

investigation.

Bendix

®

 

BASIC

™ 

Test

GENERAL SAFETY GUIDELINES

WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS

TO AVOID PERSONAL INJURY OR DEATH:

When working on or around a vehicle, the following guidelines should be observed AT ALL TIMES:

 

 Park the vehicle on a level surface, apply the 

parking brakes and always block the wheels.  

Always wear personal protection equipment.  

 

Stop the engine and remove the ignition key 

when working under or around the vehicle.  

When working in the engine compartment, 

the engine should be shut off and the ignition 

key should be removed. Where circumstances 

require that the engine be in operation, EXTREME 

CAUTION should be used to prevent personal 

injury resulting from contact with moving, 

rotating, leaking, heated or electrically-charged 

components.

 

Do not attempt to install, remove, disassemble 

or assemble a component until you have read, 

and thoroughly understand, the recommended 

procedures.  Use only the proper tools and 

observe all precautions pertaining to use of those 

tools.

 

If the work is being performed on the vehicle’s 

air brake system, or any auxiliary pressurized air 

systems, make certain to drain the air pressure 

from all reservoirs before beginning ANY work 

on the vehicle.  If the vehicle is equipped with a 

Bendix

®

 AD-IS

®

 air dryer system, a Bendix

®

 DRM

 

dryer reservoir module, or a Bendix

® 

AD-9si

®

 air 

dryer, be sure to drain the purge reservoir.

 

 Following the vehicle manufacturer ’s 

recommended procedures, deactivate the 

electrical system in a manner that safely removes 

all electrical power from the vehicle.

 

Never exceed manufacturer’s recommended 

pressures.  

 

Never connect or disconnect a hose or line 

containing pressure; it may whip and/or cause 

hazardous airborne dust and dirt particles. Wear 

eye protection. Slowly open connections with 

care, and verify that no pressure is present. Never 

remove a component or plug unless you are 

certain all system pressure has been depleted.

 

 Use only genuine Bendix

®

 brand replacement 

parts, components and kits. Replacement 

hardware, tubing, hose, fi ttings, wiring, etc. must 

be of equivalent size, type and strength as original 

equipment and be designed specifi cally for such 

applications and systems.

 

Components with stripped threads or damaged 

parts should be replaced rather than repaired.  

Do not attempt repairs requiring machining or 

welding unless specifi cally stated and approved 

by the vehicle and component manufacturer.

 

Prior to returning the vehicle to service, make 

certain all components and systems are restored 

to their proper operating condition.

 

 For vehicles with Automatic Traction Control 

(ATC), the ATC function must be disabled (ATC 

indicator lamp should be ON) prior to performing 

any vehicle maintenance where one or more 

wheels on a drive axle are lifted off the ground 

and moving.

 

The power MUST be temporarily disconnected 

from the radar sensor whenever any tests USING 

A DYNAMOMETER are conducted on a vehicle 

equipped with a Bendix

® 

Wingman

®

 system.

 

 You should consult the vehicle manufacturer's operating and service manuals, and any related literature, 

in conjunction with the Guidelines above.

Summary of Contents for SNA-01

Page 1: ...cylinder head contains air and water ports as well as an unloader assembly The discharge jumper is connected to the cylinder head and re routes the discharge air to the discharge port of the cylinder...

Page 2: ...e electrical system in a manner that safely removes all electrical power from the vehicle Never exceed manufacturer s recommended pressures Never connect or disconnect a hose or line containing pressu...

Page 3: ...rge Jumper Oil Supply Port Piston Assembly Special Fitting pre installed in coolant port Unloader Piston Sleeve Bearing Rear Cover Plate Special Fitting pre installed in inlet port FIGURE 5 CHARGING S...

Page 4: ...valve and is compressed as the piston moves upwards When air in the cylinder bore reaches a pressure greater than that of the system pressure the discharge reed valves open and allow air to flow into...

Page 5: ...bushings 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 hol...

Page 6: ...strictions to flow Minimum coolant line size is 3 8 Inside Diameter I D Check coolant lines for internal clogging from rust scale If coolant lines appear suspicious check the coolant flow and compare...

Page 7: ...pressor 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 drye...

Page 8: ...om Cover Gasket Cap Screws Plug Sleeve Bearing Plug Inlet Reed Valve Gasket Head Gasket Cylinder Head Valve Plate Assembly Piston Assembly Safety Valve Plug Discharge Jumper Washer Discharge Jumper Di...

Page 9: ...ity Description Cylinder Head Gasket Kit P N K023764 14 2 Head Gasket 17 1 Inlet Reed Valve Gasket Discharge Jumper Kit P N K092848 12 1 Bendix ST 4 Safety Valve 37 1 Discharge Jumper 38 4 Discharge J...

Page 10: ...et 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 c...

Page 11: ...intenance may only need to include portions of these instructions DISCHARGE JUMPER ASSEMBLY FITTINGS Note The discharge jumper 37 must be removed in order to remove the inlet fitting 35 and to service...

Page 12: ...ect both sides of the head gasket surfaces on the cooling plate 15 for deep gouges and nicks Also inspect the cooling plate for any cracks or other damage If found the compressor must be replaced 3 Ca...

Page 13: ...rn REAR COVER PLATE 1 Place the rear cover plate gasket 30 onto the rear cover plate 32 Note This should be the same surface that the old gasket was removed from 2 Place the gasketed side of the cover...

Page 14: ...of the port Light wrenching may be necessary To align the tube end to the position as defined in Figure 12 unscrew the fitting by the required amount but not more than one full turn Using two wrenche...

Page 15: ...equirements FIGURE 12 REQUIRED ORIENTATION OF THE INLET AND TOP COOLANT FITTINGS 2 Install any supporting brackets on the compressor in the same position s noted and marked during removal If a rear su...

Page 16: ...r 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 be...

Page 17: ...70 305 in lbs 30 5 34 5 N m M5x0 75 6g Unloader Cap 62 71 in lbs 7 8 N m M8x1 25 6h Discharge Jumper 115 133 in lbs 13 15 N m M8x1 25 6g Rear End Cover 195 213 in lbs 22 24 N m M6x1 00 6g Crankcase Co...

Page 18: ...18...

Page 19: ...urrounding area 3 0 A 5 In the supply reservoir 4 0 A 6 8 At the valves 5 0 A 8 At air dryer cartridge 7 0 A 9 In the ping tank or compressor discharge aftercooler 8 0 A 9 Symptom Page Number 1 Oil Le...

Page 20: ...h 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 fittings con...

Page 21: ...onth Every 3 Years Every 2 Years Every Year I D Vehicle Used for Column 1 Column 2 Column 3 Column 4 Column 5 Regularly scheduled maintenance is the single most important factor in maintaining the air...

Page 22: ...and thoroughly understand the recommended procedures Use only the proper tools and observe all precautions pertaining to use of those tools If the work is being performed on the vehicle s air brake s...

Page 23: ...7 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 3 0 Oil at air dryer purge exhaust or surrounding area 2 0 Oil on the...

Page 24: ...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 Q...

Page 25: ...inlet insulation may be added here or if the inlet fitting is a typical 90 fitting it may be changed to a straight or 45 fitting For more information on how to help prevent discharge line freeze ups s...

Page 26: ...lines tests all air brake system pneumatic components need to be able to pass including minimum levels of tolerance to contamination 5 0 Oil present at valves e g at exhaust or seen during servicing A...

Page 27: ...may be undersized for the application d Compressor unloader mechanism malfunction e Damaged compressor head gasket Using dash gauges verify that the compressor builds air system pressure from 85 100 p...

Page 28: ...rge line see Table A column 2 on page A 3 for recommended size and go to Test 3 on page A 14 By other restrictions e g kinks Replace the discharge line See Table A column 2 on page A 3 for recommended...

Page 29: ...y form and block the flow If instead ice blockages occur at the air dryer inlet insulation may be added here or if the inlet fitting is a typical 90 fitting it may be changed to a straight or 45 fitti...

Page 30: ...age A 15 Go to Test 2 on page A 14 Go to Test 5 on page A 15 12 0 Air dryer safety valve releases air a Restriction between air dryer and reservoir b Air dryer safety valve malfunction c Air dryer mai...

Page 31: ...31...

Page 32: ...ak at the head gasket 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 t...

Page 33: ...Test 2 Air Brake System and Accessory Leakage 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 drye...

Page 34: ...to and from the governor for restrictions e g collapsed or kinked Repair as necessary 2 Using a calibrated external gauge in the supply reservoir service reservoir or reservoir port of the Bendix D 2...

Page 35: ...nk drain schedule for vehicles equipped with a Bendix air dryer that is properly maintained If in cold weather conditions the 30 day air tank drain schedule is longer than the customer s usual drainin...

Page 36: ...engine oil loss amount described _____________ Is the engine leaking oil no yes Is the compressor leaking oil no yes Other complaint __________________________________ No customer complaint Checklist...

Page 37: ...high air use or 30 90 days low air use if oil level is at or below acceptance line for number of days if oil level is above acceptance line for number of days System OK Return to service Otherwise if...

Page 38: ...The dryer inlet air temperature should typically be within the range of no more than 160 F and no less than 45 F above low ambient surrounding temperature to prevent freeze ups For example if low ambi...

Page 39: ...ate 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 t...

Page 40: ...metallic 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 fluids into air brake lines or hose coupli...

Page 41: ...41 Log on and Learn from the Best On line training that s available when you are 24 7 365 Visit www brake school com SD 01 10142 2015 Bendix Commercial Vehicle Systems LLC All Rights Reserved 06 2015...

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