User's Manual

ManualsBrandsBENDIX ManualsCompressors And GovernorsBENDIX BW1971

*This guide is only for vehicles that use desiccant air dryers.

The guide consists of an introduction to air brake charging system components,

a table showing recommended vehicle maintenance schedules, and a

troubleshooting symptom and remedy section with tests to diagnose most

charging system problems.

Advanced Troubleshooting Guide

for Air Brake Compressors

This troubleshooting guide obsoletes and supersedes all previous published

troubleshooting information relative to Bendix

air compressors.

Air brake charging system:

Slow build (9.0) ...................9 - 10

Doesn’t build air (10.0) .................11

Air Dryer:

Doesn’t purge (14.0) ..................12

Safety valve releases air (12.0) ..........12

Compressor:

Constantly cycles (15.0) ...............13

Leaks air (16.0) ......................13

Safety valve releases air (11.0) ..........11

Noisy (18.0) ........................13

Reservoir:

Safety valve releases air (13.0) ..........12

INDEX

Air

Coolant

Engine

Oil

Compressor leaks coolant (17.0). . . . . . . . . . . . 13

Oil consumption (6.0) .....................9

Oil Test Card results (1.0) ..................4

Oil is present:

On the outside of the compressor (2.0) .....5

At the air dryer purge/exhaust

or surrounding area (3.0) ..............5

In the supply reservoir (4.0) ...........6 - 8

At the valves (5.0) .....................8

At air dryer cartridge (7.0) ...............9

In the ping tank or compressor

discharge aftercooler (8.0) .............9

Symptom Page Number

(1) Oil Leakage at Head Gasket ............14

(2) System Leakage .....................14

(3) Compressor Discharge and

Air Dryer Inlet Temperature ............14

(4) Governor Malfunction .................14

(5) Governor Control Line .................15

(6) Compressor Unloader .................15

BASIC Test Information ................17-19

Test Procedures

Maintenance Schedule and Usage Guidelines

(Table A) .................... 3

Symptom Page Number

Maintenance & Usage Guidelines

Note: The technical bulletins referenced in this

document are available at www.Bendix.com.

Summary of content (20 pages)

PAGE 1
This troubleshooting guide obsoletes and supersedes all previous published troubleshooting information relative to Bendix® air compressors. Advanced Troubleshooting Guide for Air Brake Compressors * The guide consists of an introduction to air brake charging system components, a table showing recommended vehicle maintenance schedules, and a troubleshooting symptom and remedy section with tests to diagnose most charging system problems.
PAGE 2
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.
PAGE 3
Table A: Maintenance Schedule and Usage Guidelines Regularly scheduled maintenance is the single most important factor in maintaining the air brake charging system. Column 1 Column 2 Typical Discharge Compressors Line No. of Spec'd Axles I.D. Length Vehicle Used for: Low Air Use 1/2 in. e.g. Line haul single trailer with air suspension, school bus. 5 or less High Air Use e.g.
PAGE 4
Air Brake Charging System Troubleshooting 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.
PAGE 5
Symptom: What it may indicate: What you should do: 2.0 Oil on the outside of the compressor Engine and/or other accessories leaking onto compressor. Find the source and repair. Return the vehicle to service. 2.1 Oil leaking at compressor / engine connections: (a) Leak at the front or rear (fuel pump, etc.) mounting flange.  Repair or replace as necessary. If the mounting bolt torques are low, replace the gasket. (b) Leak at air inlet fitting.  Replace the fitting gasket.
PAGE 6
Symptom: What it may indicate: 4.0 Oil in supply or service reservoir (air dryer installed) What you should do: Maintenance (a) If air brake charging system maintenance has not been (If a maintained Bendix ® performed.
PAGE 7
Symptom: 4.0 Oil in supply or service reservoir* (air dryer installed) (continued) What it may indicate: What you should do: Temperature (e) Air compressor discharge and/ or air dryer inlet temperature too high.  Inspect coolant line. Replace as necessary (I.D. is 1/2"). (f) Insufficient coolant flow. (e)  Check temperature as outlined in Test 3 on page 14. If temperatures are normal go to 4.0(h).  Inspect the coolant lines for kinks and restrictions and fittings for restrictions.
PAGE 8
Symptom: 4.0 Oil in supply or service reservoir* (air dryer installed (continued) What it may indicate: What you should do: Other (cont.) (i) Poorly filtered inlet air (poor air quality to compressor).  Check for leaking, damaged or defective compressor air inlet components (e.g. induction line, fittings, gaskets, filter bodies, etc.). Repair inlet components as needed. Note: Dirt ingestion will damage compressor and is not covered under warranty. Inspect the engine air cleaner.
PAGE 9
Symptom: What it may indicate: What you should do: 6.0 Excessive oil consumption in engine. A problem with engine or other engine accessory.  See engine service manual. 7.0 Oil present at air dryer cartridge during maintenance. Air brake charging system is functioning normally. The engine service manual has more information. Oil shown leaking from an air dryer cartridge.  Air dryers remove water and oil from the air brake charging system. A small amount of oil is normal.
PAGE 10
Symptom: 9.0 Air brake charging system seems slow to build pressure. (continued) What it may indicate: What you should do: (f) Restricted discharge line.  If discharge line is restricted:  By more than 1/16" carbon build up, replace the discharge line (see Table A, column 2, on page 3 for recommended size) and go to Test 3 on page 14.  By other restrictions (e.g. kinks). Replace the discharge line. See Table A, column 2, on page 3 for recommended size. Retest for air build.
PAGE 11
Symptom: 10.0 Air charging system doesn’t build air. What it may indicate: What you should do: (a) Governor malfunction*.  Go to Test 4 on page 15. (b) Restricted discharge line.  See 9.0(f). (c) Air dryer heater malfunction: exhaust port frozen open.  Replace air dryer heater. (d) Compressor malfunction.  Replace the compressor only after making certain the preceding conditions do not exist.
PAGE 12
Symptom: 12.0 Air dryer safety valve releases air. What it may indicate: What you should do: (a) Restriction between air dryer and reservoir.  Inspect delivery lines to reservoir for restrictions and repair as needed. (b) Air dryer safety valve malfunction.  Verify relief pressure is at vehicle or component manufacturer specifications. Replace if defective. (c) A i r d r y e r m a i n t e n a n c e n o t performed.  See Maintenance Schedule and Usage Guidelines (Table A Column 3, on page 3).
PAGE 13
16.0 Compressor leaks air Testing for leaks with soap solution. 17.0 Compressor leaks coolant 18.0 Noisy compressor (multi-cylinder compressors only) What it may indicate: What you should do: (a) C o m p r e s s o r l e a k s a i r a t connections or ports.  Check for leaking, damaged or defective compressor fittings, gaskets, etc. Repair or replace as necessary. (b) Compressor unloader mechanism malfunction.  Go to Test 6 on page 15. (c) Damaged compressor head gasket.
PAGE 14
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.
PAGE 15
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 supply reservoir, service reservoir, or reservoir port of the Bendix® D-2® governor, verify cut-in and cut-out pressures are within vehicle OEM specification. 3. If the governor is malfunctioning, replace it. Test 5: Governor Control Line 1.
PAGE 16
NOTES 16
PAGE 17
Appendix: Information about the Bendix® BASIC™ Test Kit (Bendix P/N 5013711) Bendix® Air System Inspection Cup (BASIC) Test Information Oil Units Cup Cup Cup * 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.
PAGE 18
Appendix continued: Information about the BASIC Test Kit (Bendix P/N 5013711) ® Filling in the Checklist for the Bendix Air System Inspection Cup (BASIC) Test Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer.
PAGE 19
Appendix continued: Information about the BASIC Test Kit (Bendix P/N 5013711) ® Filling in the Checklist for the Bendix Air System Inspection Cup (BASIC) Test Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer. 2. Record amount of oil found: _________ days _________ units 3. Action to take   The Technician uses the chart (label) on the BASIC test cup to help decide the action to take, based on the amount of oil found.
PAGE 20
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