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8

4.  Remove the discharge and inlet fittings, if applicable, and 

note their position on the compressor to aid in reassembly.

Note:

  If a cylinder head maintenance kit is being installed, 

stop here and proceed to PREPARATION FOR 

DISASSEMBLY.  If replacing the compressor 

continue.

5.  Remove  any  supporting  bracketing  attached  to  the 

compressor and note their positions on the compressor 

to aid in reassembly.

6.  Remove  the  flange  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 fitted, 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  specifically 

necessary to mark the relationships of the cylinder head, 

cooling plate, valve plate assembly, crankcase and cylinder 

block assembly.

A convenient method to indicate the above relationships 

is to use a metal scribe to mark the parts with numbers or 

lines.  Do not use marking methods such as chalk that can 

be wiped off or obliterated during rebuilding.

Prior to disassembly make certain that the appropriate kits 

and/or replacement parts are available.  Refer to Figure 9 

during the entire disassembly and assembly procedure.

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.

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.

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.

Summary of Contents for BA-922 COMPRESSOR

Page 1: ...e 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...

Page 2: ...hes the cutout 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...

Page 3: ...oolant ow connections See the tabulated technical data in the back of this manual for speci c requirements PREVENTATIVE MAINTENANCE Regularly scheduled maintenance is the single most important factor...

Page 4: ...rticularly oil sensitive systems the Bendix PuraGuard system lter can be used in conjunction with a Bendix air dryer If compressor oil passing is suspected refer to the TROUBLESHOOTING section and TAB...

Page 5: ...he performance degrades signi 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...

Page 6: ...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...

Page 7: ...s leading to the compressor 3 Remove as much road dirt and grease from the exterior of the compressor as possible FIGURE 9 BA 922 COMPRESSOR EXPLODED VIEW OF SERVICEABLE PARTS Item Qty Description Ite...

Page 8: ...e balance piston 4 and its spring 5 from the cylinder head 5 Remove the six hex head bolts and washers from the cylinder head 6 Remove the two bolts located in the center of the head Gently tap the he...

Page 9: ...y 12 Example 12 Inch Pounds 1 Foot Pound 12 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 COV...

Page 10: ...o 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 comp...

Page 11: ...Test Information 26 28 Test Procedures Maintenance Schedule and Usage Guidelines Table A 13 Symptom Page Number Maintenance Usage Guidelines TORQUE SPECIFICATIONS Assembly Torques in inch pounds in I...

Page 12: ...perating 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...

Page 13: ...days Every Month 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 mainta...

Page 14: ...TION 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 as semble...

Page 15: ...011327 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 c 2 0 Oil...

Page 16: ...ithin the acceptable level If within the normal range return the vehicle to service For vehicles with acces sories that are sensitive to small amounts of oil consider a Bendix PuraGuard QC oil coalesc...

Page 17: ...nlet insulation may be added here or if the inlet tting is a typical 90 degree tting it may be changed to a straight or 45 degree tting For more information on how to help prevent discharge line freez...

Page 18: ...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 Air br...

Page 19: ...ay 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 ps...

Page 20: ...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 Re place the discharge line See Table A col umn 2 on page 13 for recommended size...

Page 21: ...orm and block the ow If instead ice blockages occur at the air dryer inlet insulation may be added here or if the inlet tting is a typical 90 degree tting it may be changed to a straight or 45 degree...

Page 22: ...Test 4 on page 25 Go to Test 2 on page 24 Go to Test 5 on page 25 12 0 Air dryer safety valve releases air a Restriction between air dryer and reservoir b Air dryer safety valve malfunction c Air drye...

Page 23: ...t 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 then...

Page 24: ...ry 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 d...

Page 25: ...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 D 2 govern...

Page 26: ...ician inspects items drained and f days Use Test 2 Air Leakage Use Test 2 Air Leakage NO Re test with the BASIC Test after 30 days NO did not know when last drained Was the number of days since last d...

Page 27: ...l loss amount described ______________ Is the engine leaking oil no yes Is the compressor leaking oil no yes Other complaint _____________________________________ No customer complaint Checklist for T...

Page 28: ...h 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 the...

Page 29: ...ome periods of extended engine idling can not be avoided Discharge Lines The discharge line should slope downward from the compressor discharge port without forming water traps kinks or restrictions C...

Page 30: ...through the use of an automatic drain valve periodic manual draining is still required Alcohol Evaporator or Injector Systems Check for proper operation of these systems by monitoring alcohol consump...

Page 31: ...c parts of valves and melting or burning non metallic air lines WARNING THIS PRACTICE IS UNSAFE AND CAN RESULT IN VEHICLE FIRE 2 Do not introduce pour uids into air brake lines or hose couplings glad...

Page 32: ...32 BW2398 2005 Bendix Commercial Vehicle Systems LLC All rights reserved 10 2005 Printed in U S A...

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