BENDIX SD-01-670 User Manual

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Bendix® DuraFlo 596™ Air Compressor

SD-01-670

DISCHARGE

VALVE

VALVE BODY

ASSEMBLY

PISTON

PISTON RINGS

CRANKSHAFT

DISCHARGE

VALVE HOLDER

CONNECTING

ROD

CYLINDER HEAD

CRANKCASE

CYLINDER

HEAD

VALVE BODY

ASSEMBLY

UNLOADER

PORT

CRANKCASE

WATER

INLET

PORT (2)

DISCHARGE

SAFETY VALVE

WATER OUTLET PORT (1)

REAR END

COVER OIL

PORT

CRANKCASE

BOTTOM

COVER (2)

DESCRIPTION

The function of the air compressor is to provide and maintain air under pressure to operate devices in the air brake and/or auxiliary air systems. The DuraFlo 596 compressor is a two cylinder reciprocating compressor with a rated displacement of 27 cubic feet per minute at 1250 RPM.

The compressor consists of a water cooled cylinder head and valve body assembly and an air cooled integral crankcase and cylinder block. The cylinder head is an aluminum casting which contains the required air and water ports as well as inlet check valves for each cylinder. The valve body assembly consists of steel upper and lower halves, each of which incorporate various valve openings and channels for conducting air and engine coolant into and out of the cylinder head. The discharge valves for each cylinder are part of the valve body assembly. The valve

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DISCHARGE

CAVITY

DISCHARGE

VALVE

DISCHARGE

PORTS (2)

CYLINDER BORE

PISTON

DISCHARGE VALVE

HOLDER

VIEW OF CYLINDER HEAD AND ONE CYLINDER BORE

FIGURE 1 - DURAFLO 596™ AIR COMPRESSOR

The DuraFlo

596™ compressor incorporates an unloader system that features an energy saving system or ESS which reduces compressor power consumption by approximately 80% in the unloaded mode. The ESS also reduces compressor oil consumption (oil passing) when the compressor is in the unloaded mode.

A nameplate identifying the compressor piece number and serial number is attached to the end of the cylinder block opposite the drive end.

OPERATION

DETROIT DIESEL CATERPILLAR

FIGURE 2 - TYPICAL COMPRESSOR DRIVE FLANGES

body assembly is secured to the cylinder head assembly using two cap screws and the cylinder head is secured to the cylinder block with six cap screws. The cylinder head, with the valve body halves, comprise a complete cylinder head assembly.

The cast iron crankcase and cylinder block assembly, houses the pistons, connecting rods, crankshaft and related bearings. Unloader plungers and related seals and springs are contained in bores in the cylinder block. Sliding inlet valves and their pivot arms are sandwiched between the cylinder block and valve body assembly.

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 remote mounted governor and synchro valve. Unlike the Tu-Flo compressor series, the DuraFlo 596

™

compressor

requires the addition of a synchro valve to assure proper operation and service life. The governor and synchro valve combination maintains brake system air pressure between a preset maximum and minimum pressure level. Refer to Figure 3.

The compressor has a built in unloading and ESS or Energy Saving System.

AIR INTAKE (LOADED)

The piston strokes are 180 degrees opposed. As one piston is on an up stroke the opposing piston is on a down stroke. During the piston down stroke, a vacuum is created in the cylinder and ESS chamber within the cylinder head. The vacuum causes the inlet check valve and sliding inlet valve to ﬂ ex open. Atmospheric air ﬂ ows through the open inlet check valve into and through the ESS chamber to the sliding inlet valve. Air ﬂ owing past the sliding inlet valve ﬁ lls the cylinder above the piston. See Figures 4 & 7.

AIR

DRYER

DURAFLO COMPRESSOR

FIGURE 3 - DURAFLO 596™ AIR COMPRESSOR UNLOADER SYSTEM

SYNCHRO VALVE

™

596

GOVERNOR

COMPRESSOR

UNLOADERS

TO AIR

DRYER

SUPPLY

RESERVOIR

DELIVERY

SUPPLY

SYNCHRO

VALVE

CONTROL

FROM

SUPPLY

RESERVOIR

GOVERNOR

(110 CUT-IN 130

CUTOUT)

FROM

SUPPLY

RESERVOIR

AIR INLET PORT

ESS

CHAMBER

INLET VALVE OPEN

INLET CHECK

VALVE OPEN

AIR

DISCHARGE

PORT

DISCHARGE

VALVE

CLOSED

AIR INLET PORT

ESS

CHAMBER

INLET

VALVE

OPEN

INLET CHECK VALVE

CLOSED

AIR

DISCHARGE

PORT

DISCHARGE

VALVE

CLOSED

UNLOADER

PISTON

MOVING

DOWN

FIGURE 4 - OPERATIONAL-LOADED (INTAKE)

AIR COMPRESSION (LOADED)

When the piston reaches approximately bottom dead center (BDC) the inlet check valve and sliding inlet valve close. Air above the piston is trapped by the closed inlet 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 valves open and air ﬂ ows into the discharge line and air brake system.

AIR INLET PORT

ESS

CHAMBER

INLET

VALVE

CLOSED

INLET CHECK VALVE

CLOSED

PISTON MOVING

FIGURE 5 - OPERATIONAL-LOADED (COMPRESSION)

AIR

DISCHARGE

PORT

DISCHARGE

VALVE OPEN

UNLOADER

PISTON

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 control port of the synchro valve. The synchro valve opens in response to control pressure from the governor and delivers system pressure to either of the two compressor unloader ports. Air entering the

UNLOADER PISTON

& PIVOT ARM SLIDES

PISTON MOVING

UP & DOWN

INLET VALVE OVER

FIGURE 6 - OPERATIONAL-UNLOADED

unloader port acts on one unloader plunger directly and is simultaneously conducted through a passage in the valve body assembly to the other unloader plunger.

The unloader plungers move horizontally in their bores in response to control pressure from the governor and synchro valve. A guide pin in the unloader plunger rotates the pivot arm which causes the inlet valve to slide. As the inlet valve slides from the loaded to the unloaded position it blocks the two discharge ports and opens the six inlet ports connecting the cylinder bore to the ESS chamber. When the piston travels upward, air in the cylinder is trapped between the top of the piston and the closed inlet check valve and is compressed. The intake check valves prevent the intake air from escaping through the air intake port when the compressor is in the unloaded ESS mode. See Figures 5 & 7.

The added volume of the ESS chamber lowers the amount of compression. Air that is compressed during the upward movement of the piston provides a driving force for the piston during its downward movement. As one piston is moving downward the opposing piston is moving up. With the exception of losses in the form of heat, which is formed during compression, the energy used to compress the air will be reused as the driving force for the downward stroke of the piston. This results in the compressor using very little power in its unloading position. See Figures 6 & 7.

DuraFlo

596™ compressors can also be discharge line unloaded which would eliminate the need for the synchro valve, however, the power savings associated with the ESS system would not be realized.

DISCHARGE VALVE

DISCHARGE PORTS

CYLINDER HEAD SIDE OF VALVE BODY ASSEMBLY

DISCHARGE

PORTS

COMPRESSOR LOADED

CYLINDER BLOCK SIDE OF VALVE BODY ASSEMBLY

INLET PORTS

SLIDING INLET

VALVES

PIVOT ARMS

COMPRESSOR UNLOADED

INLET

PORTS

air dryer is not used to remove these contaminants prior to entering the air system, the majority, but not all, will condense in the reservoirs. The quantity of contaminants that reach the air system depends on several factors including installation, maintenance and contaminant handling devices in the system. These contaminants must either be eliminated prior to entering the air system or after they enter.

DUTY CYCLE

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. Refer to Table A in the T roubleshooting section for a guide to various duty cycles and the consideration that must be given to maintenance of other components.

UNLOADER

PORT

UNLOADER AIR

PASSAGE

PIVOT

ARM

SLIDING

INLET VALVE

FIGURE 7 - UNLOADER MECHANISM

UNLOADER

PLUNGER

GUIDE PIN

COMPRESSOR & THE AIR BRAKE SYSTEM

GENERAL

The compressor is part of the total air brake system, more speciﬁ cally, the charging portion of the air brake system. As a component in the overall system its condition, duty cycle, proper installation and operation will directly affect other components in the 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, lubricated by the engine oil supply and has its inlet connected to the engine induction system.

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. If an

COMPRESSOR INSTALLATION

While the original compressor installation is usually completed by the vehicle manufacturer, conditions of operation and maintenance may require additional consideration. The following presents base guidelines.

DISCHARGE LINE

The discharge line allows the air, water-vapor and oil-vapor mixture to cool between the compressor and air dryer or reservoir. The typical size of a vehicle's discharge line, (see column 2 of Table A in the Troubleshooting section) 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.

The discharge line must maintain a constant slope down from the compressor to the air dryer inlet ﬁ tting or reservoir to avoid low points where ice may form and block the ﬂ ow. If, instead, ice blockages occur at the air dryer or reservoir 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. Shorter discharge line lengths or insulation may be required in cold climates.

While not all compressors and charging systems are equipped with a 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.

DISCHARGE LINE

OPTIONAL “PING” TANK

AIR DRYER

The Air Brake Charging System supplies the

compressed air for the braking system, as well as other air accessories for the vehicle. The system usually consists of an air compressor, governor, discharge line, air dryer, and service reservoir.

COMPRESSOR

(GOVERNOR PLUS SYNCHRO VALVE

FOR THE BENDIX

FIGURE 8A - SYSTEM DRAWING

THREAD

FIGURE 8B - DISCHARGE LINE SAFETY VALVE

GOVERNOR

DURAFLO 596™

COMPRESSOR)

HOLE

DISCHARGE LINE TEMPERATURE

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 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 recommend installation of a Bendix PuraGuard® QC oil coalescing ﬁ lter, designed to minimize the amount of oil present.

OPTIONAL BENDIX® PURAGUARD® QC

OIL COALESCING FILTER

SERVICE RESERVOIR (SUPPLY RESERVOIR)

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RESERVOIR DRAIN

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 is returned to the engine. Proper cooling is important in maintaining discharge air temperatures below the maximum recommended 400 degrees Fahrenheit. Figure 9 illustrates the various approved coolant ﬂ ow connections. See the tabulated technical data in the back of this manual for speciﬁ c requirements.

AIR INDUCTION

The DuraFlo 596™ compressor is approved for natural aspiration only. The compressor inlet is connected to the vacuum side of the engine air induction system. 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 the 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.

AIR INDUCTION

One of the single most important aspects of compressor preventive maintenance is the induction of clean air. Since the DuraFlo 596™ is connected to the engine air cleaner, proper periodic maintenance of the engine air ﬁ lter eliminates the need for separate ﬁ lter maintenance.

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 if necessary.

13 X 60MM

13 X 85MM CYL. BOLT

(6)

COOLANT IN

OR OUT

(ONE OR

THE OTHER

PLUGGED)

CYLINDER HEAD PORT IDENTIFICATION

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

FIGURE 9 - TYPICAL DURAFLO 596™ AIR COMPRESSOR CYLINDER HEAD

CYL. BOLT (2)

DISCHARGE

SAFETY VALVE

Atmospheric AIR IN 0 Compressed AIR OUT 2 Coolant IN 91 Coolant OUT 92

LIFTING

LUG

INLET PORT

DISCHARGE

PORT

COOLANT

IN OR OUT

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

COMPRESSOR COOLING

Inspect the compressor discharge port, inlet cavity and discharge line for evidence of restrictions and carboning. If excessive buildup is noted, thoroughly clean or replace the affected parts. Since carbon buildup 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 present 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 the back of this

Supply lines must be a minimum of 3/16"

manual for oil pressure minimum values. Check the exterior of the compressor for the presence of

oil seepage and refer to the TROUBLESHOOTING section for appropriate tests and corrective action.

OIL PASSING

All reciprocating compressors currently manufactured will pass a minimal amount of oil. Air dryers will remove the majority of oil prior to entrance into the air brake system. For particularly oil sensitive systems the Bendix

PuraGuard® QC oil coalescing filter can be used in conjunction with a Bendix air dryer.

If compressor oil passing is suspected, refer to the TROUBLESHOOTING section and TABLE A for the symptoms and corrective actions to be taken. In addition, Bendix has developed the "Bendix Air System Inspection Cup" or BASIC™ test to help substantiate suspected excessive oil passing. The steps to be followed when using the BASIC™ test 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 & GOVERNOR UNLOADER SYSTEM

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

1. Make certain the unloader system contains both the governor and synchro valve as illustrated in Figure 3.

2. Cycle the compressor through the loaded and unloaded cycle several times. Make certain that the governor cuts out at 130 psi (cut-in should be approximately 1 10 psi). Adjust or replace the governor as required.

™

3. Note that the DuraFlo 596 loaded and unloaded conditions promptly . This can be deﬁ nitely conﬁ rmed by installing a test gauge in the unused unloader port on the compressor and observing the reaction during transition from the loaded and unloaded condition. Air pressure should be applied and exhausted with a distinct “snap action” with no appreciable lag for buildup or release of pressure. If prompt action is not noted, repair or replace the synchro valve.

compressor cycles to the

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.

OPERATING TESTS

Compressor Performance

Vehicles manufactured after the effective date of FMVSS 121 must have a compressor capable of raising air system pressure from 85-100 psi in 25 seconds or less, with the minimum required reservoir volume for the vehicle. This test is performed with the engine operating at maximum recommended governed speed. The vehicle manufacturer must certify this performance on new vehicles with appropriate allowances for air systems with greater than the minimum required reservoir volume. As a less severe alternative to running a high RPM test, a new compressor's buildup time can be measured and recorded at high idle. Subsequent testing throughout the compressor’s service life can be compared to the base line new compressor performance. Compressor buildup times should be recorded and kept with the vehicle maintenance ﬁ les for reference. When testing compressor buildup times it is essential that air system leakage be kept below the allowed maximum for the vehicle type being tested. Before running buildup tests, check the service and supply systems for excessive leakage and repair as necessary.

Note: Supply system leakage is not displayed on the

vehicle dash gauges and must be tested separately. Supply system components such as the governor, synchro valve, air dyer, reservoir drain cocks, safety valve and check valves can leak without indication on the dash gauges. These components must be checked for leakage separately and individually. 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) for air system leakage testing.

LEAKAGE TESTS

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 body assembly and the gasket between the valve body 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 authorized Bendix parts outlets.

Inlet, Discharge & Unloader

While it is possible to test for inlet, discharge, and unloader plunger leakage it requires disassembly of the cylinder head to accomplish. For this reason it is not recommended.

Inlet and discharge valve leakage can generally be detected by longer compressor buildup and recovery times. Compare current compressor buildup times with the last several recorded times. Make certain to test for Air system leakage, as described under Operating Tests, before making a determination that performance has been lost.

1. With the engine running, lower air system pressure to 90 psi and raise engine RPM to 1800. Measure and record the time required to raise system pressure from 100 psi to 130 psi. Run this test three times and use the average time.

Note: This test should be run with the engine and air system at normal operating temperature (i.e. not cold).

2. Compare the average time recorded in step 1 with previously recorded build up times to evaluate compressor performance.

CYLINDER

HEAD

VALVE BODY

ASSEMBLY

7 6

5 4

5 4 3

CRANKCASE

CYLINDER

BLOCK

FLANGE

MOUNT

COMPRESSOR

END COVER

Item Qty. Description Item Qty. Description Item Qty Description

1 6 13mm x 85mm Bolt 12 2 Discharge Valve 23 2 Backup Ring 2 2 13mm x 60mm Bolt 13 2 Sliding Inlet Valve 24 2 Spring 3 2 10mm x 25mm Bolt 14 2 Pivot Arm 25 6 13mm Washer 4 2 Spacer Sleeve 15 2 Stud 26 1 Discharge Safety Valve 5 2 Holder 16 2 Guide Pin 27 2 Base Plate Gasket 6 2 Inlet Check Valve 17 2 Guide Pin 28 8 Base Plate Cap Screw 7 2 Seat 18 1 Vlv. Asm. to Block Gskt. 29 2 Base Plate 8 1 Head to Valve Asm. Gskt. 19 1 Plug 30 1 End Cover O-Ring 9 4 10mm x 25mm Bolt 20 1 Sealing Washer 31 4 13mm x 20mm Bolt 10 4 Spacer Sleeve 21 2 Unloader Plunger 11 2 Holder 22 2 O-Ring

FIGURE 10 - DURAFLO

596™ AIR COMPRESSOR EXPLODED VIEW OF SERVICEABLE PARTS

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, replace the compressor 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 and the instructions provided with these parts and kits should be followed in lieu of the instructions presented here.

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 an AD-IS a dryer reservoir module, 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.

air dryer system or

MAINTENANCE KITS & SERVICE PARTS

Cylinder Head Maintenance Kit. Unloader Maintenance Kit. All components shown in Figure 10 with a key number are

available in kits and/or as individual service parts.

COMPRESSOR TROUBLESHOOTING

IMPORTANT: The troubleshooting contained in this section

considers the compressor as an integrated component of the overall air brake charging system and assumes that an air dryer is in use. The troubleshooting presented will cover not only the compressor itself, but also other charging system devices as they relate to the compressor.

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 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.

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® replacement parts, 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 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 (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.

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

REMOVAL

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, precautions and procedures presented in this manual.

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.

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 or unloader maintenance kit is being installed, stop here and proceed to PREP ARATION 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. Before the compressor is disassembled, the following items should be marked to show their relationship when the compressor is assembled. Mark the rear end cover or end cover adapter in relation to the crankcase. Mark the relationship of the cylinder head to the valve body assembly and 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 10 during the entire disassembly and assembly procedure.

UNLOADER & INLET VALVE

1. Remove the discharge safety valve (26) from the cylinder head.

2. Remove the unloader port plug and sealing washer (19 & 20).

3. Loosen but do not remove the two 13mm x 60mm bolts (2).

4. Remove the six 13mm x 85mm cylinder head bolts and washers (1 & 25) and tap the head with a soft mallet to break the gasket seal. Lift the cylinder head and valve body assembly off the cylinder block.

IMPORTANT NOTE: Do not attempt to separate the two halves of the valve body assembly. Service replacements and gaskets are not available.

5. Remove the metal gasket (18).

6. Remove both sliding inlet valves (13).

7. Remove both pivot arms (14) and pivot arm studs (15).

8. To remove spring tension from the unloader plunger guide pin (16), insert a 1/4” brass dowel into one of the unloader plunger bore and depress the plunger (21) slightly . While holding the plunger (21) depressed, remove the plunger guide pin (16). Slowly extract the dowel rod from the unloader bore until spring tension is relieved.

Note: As an alternative, to this procedure an appropriately sized nut or dowel rod can be placed in the unloader bore and the plug (19) installed then removed after the guide pin is removed.

9. Remove the unloader plunger (21), with its o-ring (22) and backup ring (23) from the bore. Remove the unloader spring (24).

10. Repeat steps 7 and 8 for the other unloader plunger.

11. Remove both pivot arm guide pins (17) from the cylinder block.

DISCHARGE & INLET CHECK VALVES

1. Remove the two 13mm x 60mm cylinder head bolts (2) and gently tap the head and valve body assembly with a soft mallet to break the gasket seal. Separate the cylinder head and valve body assembly.

IMPORTANT NOTE: Do not attempt to separate the two halves of the valve body assembly. Service replacements and gaskets are not available.

2. Remove the gasket (8).

3. Turn the cylinder head over to expose the inlet check valves and remove the 10mm x 25mm inlet check valve bolt (3) that secures the inlet check valve components. Remove the spacer sleeve (4), holder (5), check valve (6) and check valve seat (7).

4. Repeat step 3 for the second inlet check valve assembly.

5. Remove the two 10mm x 25mm discharge valve bolts (9) that secure the discharge check valve components. Remove the spacer sleeve (10), holder (11) and discharge valve (12).

6. Repeat step 5 for the second discharge valve assembly.

CRANKCASE COVER

1. Remove the four cap screws (28) securing the crankcase cover (29). Using a soft mallet, gently tap the crankcase cover (29) to break the gasket seal. Scrape off any gasket material (27) from the crankcase and bottom cover or adapter.

2. Repeat step 1 for the second crankcase cover.

END COVER OR END COVER ADAPTER

1. Remove the cap screws (31) that secure the rear end cover or end cover adapter to the crankcase.

Note: Some compressor models use four cap screws while others use a combination of cap screws and studs.

2. Remove the rear end cover or end cover adapter from the crankcase. Remove the o-ring seal (30) from the end cover if so equipped.

CLEANING OF PARTS

GENERAL

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

OIL PASSAGES

Thoroughly clean all oil passages through the end cover or end cover adapter. Inspect the passages with a wire to be sure. Blow the loosened foreign matter out with air pressure.

CYLINDER BLOCK UNLOADER BORES

Thoroughly clean the unloader bore on both sides of the compressor cylinder block. Make certain not to scratch or gouge the air pressure sealing surfaces of the bores during the cleaning process.

INSPECTION OF PARTS

CYLINDER HEAD & VALVE BODY

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 body gasket surfaces for deep gouges and nicks. Pay particular attention to the metal gasket surface. A metal gasket (18) is used between the valve body assembly and 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 body, 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.

CYLINDER HEAD

1. Carefully remove all gasket material adhering to the cylinder head, valve body assembly and 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 body assembly . Make certain the inlet and discharge ports of the valve body assembly are open and clear.

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

4. Make certain the unloader air passages and coolant passages through the valve body are open and clear of contamination.

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

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.

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 at the end of this manual. INCH POUNDS TO FOOT POUNDS To convert inch pounds to foot pounds of torque, divide inch pounds by 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

CRANKCASE COVER

1. Position one of the two crankcase cover gaskets (27) on either the crankcase or crankcase cover and install the crankcase cover (29) using the position marks made prior to disassembly . T ighten the four cap screws (28), securing the crankcase cover to a torque of 101-111 inch pounds for crankcase cover or cover in a crossing pattern after ﬁ rst snugging all 4 screws.

2. Repeat this assembly for the second crankcase cover (29).

CRANKCASE END COVER OR END COVER ADAPTER

1. Install the end cover o-ring (30) 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 13mm x 20mm end cover or end cover adapter bolts or studs (31) and tighten to 195 to 212 inch pounds.

CYLINDER HEAD INLET CHECK VALVES

1. Locate one of the two inlet check valve seats (7) and note that one side is ﬂ at while the other has three protruding tabs around the bolt hole. Position one of the two inlet check valves (6) on the inlet check valve seat (7) so that the three positioning and locating tabs interlock with the corresponding tabs on the seat. When properly ﬁ tted together, the valve (6) should lay ﬂ at against the seat (7) and cover the slotted opening of the seat.

x 12 = 12 Inch Pounds

2. Locate one of the two inlet check valve holders (5). Place the holder (5) on the inlet check valve (6) making certain that the three indentations around the bolt hole, on the holder, interlock with the tabs on the inlet check valve (5). When properly assembled the seat (7), valve (6) and holder (5) should be parallel and interlocked.

3. Place the three components over one of the two slotted inlet openings in the cylinder head making certain that the bolt holes in the components and head correspond.

4. Insert one of the two 10mm x 25mm bolts (3) through a spacer sleeve (4). Using the bolt and sleeve, secure the assembled seat (7), valve (6) and holder (5) in the cylinder head. Tighten the bolt ﬁ nger tight and check that the seat (7), valve (6) and holder (5) are still interlocked. This can be done by attempting to rotate the holder (5) and noting that the valve and seat follow and are locked together.

5. Torque the 10mm bolt to 101 to 111 inch pounds.

6. Repeat steps one through ﬁ ve for the other inlet check valve assembly.

DISCHARGE VALVES

1. Locate and place one of the two discharge valves (12) on the valve body assembly with its bolt hole corresponding with the threaded hole on the outside edge of the valve body assembly. When correctly placed, the discharge valve (12) will cover the two discharge holes in the valve body assembly. Refer to Figure 11.

DISCHARGE VALVE

HOLDER

GUIDE LUG

DISCHARGE VALVE BOLT

HOLE

FIGURE 11 - DISCHARGE VALVE INSTALLATION

2. Locate one of the two discharge valve holders (11) and install it over the discharge valve (12) so that the free end of the discharge valve (12) is contained between the two guide lugs on the sides of the holder. Refer to Figure 11.

3. Insert one of the four 10mm x 25mm bolts (9) through a spacer sleeve (10). Using the bolt and sleeve, loosely secure one end of the discharge valve (12) and holder (11) to the valve body assembly. Insert a second 10mm x 25mm bolt (9) through a spacer sleeve (10) and loosely secure the other end of the discharge valve (12) and holder (1 1) to the valve body assembly.

VALVE

BODY

ASSEMBLY

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