BENDIX TU-FLO 400, TU-FLO 500, TU-FLO 1000 User Manual

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Bendix® TU-FLO® 400, 500, 1000 Air Compressors

SD-01-326

TU-FLO® 400 Air Compressor TU-FLO® 500 Air Compressor

TU-FLO

1000 Air Compressor

DESCRIPTION AND OPERATION

GENERAL

The function of the air compressor is to build up and maintain the air pressure required to operate air powered devices in air brake or air auxiliary systems.

DESCRIPTION

Tu-Flo® Type 400, 500, and 1000 compressors are single stage, reciprocating piston type compressors. Tu-Flo (Fig. 1) and 500 (Fig. 2) compressors have two cylinders while the Tu-Flo

1000 compressor (Fig. 3) is a V-type design having four cylinders. The rated capacity of all Bendix compressors is their piston displacement in cubic feet per minute when operating at 1,250 RPM. The rated capacity of the Tu-Flo® 400 compressor is 7-1/4 cubic feet per minute.

The Tu-Flo minute and the Tu-Flo

500 compressor is rated at 12 cubic feet per

1000 compressor has a rating of 24

cubic feet per minute. Tu-Flo® type compressors have automatic type inlet valves.

Their unloading mechanisms are located in the cylinder block

400

and they have no external moving parts. Both air and water cooled type compressors are available. V arious mounting and drive adaptations are used as required by different vehicle engine designs (Fig. 4).

FIGURE 1 - TU-FLO® 400 AIR COMPRESSOR

FIGURE 2 - TU-FLO® 500 AIR COMPRESSOR

FIGURE 3 - TU-FLO® 1000 AIR COMPRESSOR

FIGURE 4 - VARIOUS COMPRESSOR MOUNTINGS

Compressors are either engine or self-lubricated. The majority used are the engine lubricated types (Fig. 5) which obtain the oil necessary to lubricate their moving parts from the engines on which they are mounted. To meet the requirements of some manufacturers and for field installations, self-lubricated types (Fig. 6) are available. They are compressors having a self-contained oil supply and pumping system.

The method of lubricating the moving parts of the compressor is the same in either type. Oil is forced through the oil passage in the crankshaft and out around each connecting rod journal. The turning motion of the crankshaft throws the oil that is forced out at the journals, against the cylinder bores and crankcase walls, lubricating the bores and crankshaft bearings.

The wrist pins and wrist pin bushings are lubricated in two ways depending upon the type connecting rods used. Older design compressors had forged steel rifle-drilled rods through which oil was forced to the wrist pin bushings. Later versions

FIGURE 5

ENGINE LUBRICA TED TYPE

FIGURE 6

SELF-LUBRICATED TYPE

had either die cast aluminum, cast ductile iron, or forged steel rods which were not rifle drilled but were drilled at the top of the rod. The wrist pins and bushings are lubricated by oil dripping from a drip-boss on the piston into a “catch-funnel” at the top of the rod and through the drilled passage to the bushings and pins. (SEE FIG. 7)

PISTON WRIST PIN

LOCK WIRE

WRIST PIN

BUSHING

OPERATION

GENERAL

All compressors run continuously while the engine is running, but actual compression of air is controlled by a governor, which stops or starts the compression of air by loading or unloading the compressor in conjunction with its unloading mechanism. This is done when the air pressure in the system reaches the desired maximum or minimum pressures.

TO RESERVOIR

DISCHARGE

VALVE

PISTON

INLET VALVE

UNLOADER PLUNGER

INTAKE

STRAINER

TO GOVERNOR

WRIST PIN

OIL

PASSAGE

OLD DESIGN

WRIST PIN

BUSHING

NEW DESIGN

FIGURE 7- PISTONS & CONNECTING RODS

CONNECTING

“CATCH FUNNEL”

CAST IRON

PISTON

STEEL

ROD

DIE CAST

PISTON

DIE CAST

CONNECTING ROD

A nameplate is attached to the crankcase of all compressors. It shows the piece number, type and serial number (Fig. 8). A nameplate with a black background denotes a new compressor, whereas a nameplate with a red background designates that the compressor is a factory reconditioned unit. All compressors are identified by the piece number which is the number to use when reference is made to a particular compressor. The type and serial number is supplementary information.

STROKE

INTAKE

FIGURE 9

INT AKE AND COMPRESSION (Loaded)

During the down stroke of the piston, a slight vacuum created above the piston causes the inlet valve to move off its seat. Atmospheric air is drawn in through the compressor intake, by the open inlet valve, and on top of the piston (Fig. 9). As the piston starts its upward stroke, the air that was drawn in on the down stroke is being compressed. Now, air pressure on top of the inlet valve plus the force of its spring, returns the inlet valve to its seat. The piston continues the upward stroke and compresses the air sufficiently to overcome the discharge valve spring and unseat the discharge valve. The compressed air then flows by the open discharge valve, into the discharge line and on to the reservoirs (Fig. 10).

TO RESERVOIR

DISCHARGE

VALVE

PISTON

INLET VALVE

UNLOADER PLUNGER

INTAKE

STRAINER

FIGURE 8 - COMPRESSOR NAMEPLATE

TO GOVERNOR

STROKE

COMPRESSION

FIGURE 10

As the piston reaches the top of its stroke and starts down, the discharge valve spring returns the discharge valve to its seat. This prevents the compressed air in the discharge line from returning to the cylinder bore as the intake and compression cycle is repeated.

NON-COMPRESSION (Unloaded)

When the air pressure in the reservoir reaches the high pressure setting of the governor, the governor opens, allowing air to pass from the reservoir through the governor and into the cavity beneath the unloader pistons. This lifts the unloader pistons and plungers. The plungers move up and hold the inlet valves off their seats (Fig. 1 1).

TO RESERVOIR

DISCHARGE

VALVE

PISTON

STROKE

FIGURE 1 1

INLET VALVE

UNLOADER

PLUNGER

INTAKE

STRAINER

TO GOVERNOR

UNLOADING

With the inlet valves held off their seats by the unloader pistons and plungers, air is merely pumped back and forth between the two cylinders. When air is used from the reservoir and the pressure drops to the low pressure setting of the governor, the governor closes, and in doing so, exhausts the air from beneath the unloader pistons. The unloader saddle spring forces the saddle, pistons and plungers down and the inlet valves return to their seats. Compression is then resumed.

COMPRESSOR & THE AIR BRAKE SYSTEM

GENERAL

The compressor is part of the total air brake system, more specifically, 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 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 fittings, connections, lines, chambers or valves, etc. Refer to T able A in the Troubleshooting section for a guide to various duty cycles and the consideration that must be given to maintenance of other components.

COMPRESSOR INST ALLATION

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 T able 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 fitting or reservoir to avoid low points where ice may form and block the flow . If, instead, ice blockages occur at the air dryer or reservoir inlet, insulation may be added here, or if the inlet fitting is a typical 90 degree fitting, it may be changed to a straight or 45 degree fitting. 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 freezeup.

DISCHARGE LINE TEMPERA TURE

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 oilvapor 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.

Discharge Line

Optional “Ping” T ank

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

(Governor plus Synchro valve

for the Bendix

FIGURE 12A - SYSTEM DRAWING

THREAD

FIGURE 12B - DISCHARGE LINE SAFETY VALVE

DuraFlo™ 596

Compressor)

HOLE

Optional Bendix® PuraGuard® QC

™

Oil Coalescing Filter

Service Reservoir

(Supply Reservoir)

Reservoir Drain

PREVENTIVE MAINTENANCE

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

If the compressor is a self-lubricated type, its oil level should be checked daily . The oil level should be kept between the bottom of the dipstick threads and the bottom of the dipstick (Fig. 13). Every 8,000 miles or 300 operating hours, the oil should be drained and refilled with SAE 10-20-30.

The air dryer contains a filter 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 filter, designed to minimize the amount of oil present.

COOLING

Tu-Flo® 400, 500 or 1000 compressors may be air-cooled or water- cooled and in some instances will have air-cooled blocks and water-cooled heads. The air-cooled versions are easily recognized by the external fins. The water-cooled versions are cooled by vehicle coolant.

FIGURE 13 - OIL LEVEL - SELF-LUBRICATED COMPRESSOR

POL YURETHANE SPONGE STRAINER (Fig. 14)

Remove and wash all of the parts. The strainer element should be cleaned or replaced. If the element is cleaned, it should be washed in a commercial solvent or a detergent and water solution. The element should be saturated in clean engine oil, then squeezed dry before replacing it in the strainer. Be sure to replace the air strainer gasket if the entire air strainer is removed from the compressor intake.

FIGURE 16 - COMPRESSOR INTAKE ADAPTER

FIGURE 14 - POLYURETHANE SPONGE STRAINER

FIGURE 15 - DRY ELEMENT - PLEA TED P APER AIR

STRAINER

DRY ELEMENT - PLEATED PAPER AIR STRAINER (FIG. 15)

Remove the spring clips from either side of mounting baffle and remove the cover. Replace the pleated paper filter and remount the cleaned cover making sure the filter is in position. Be sure to replace the air strainer gasket if the entire air strainer is removed from the compressor intake. (NOTE: Some compressors are fitted with compressor intake adapters (Fig. 16) which allow the compressor intake to be connected to the engine air cleaner.) In this case, the compressor receives a supply of clean air from the engine air cleaner. When the engine air filter is changed, the compressor intake adapter should be checked. If it is loose, remove the intake adapter, clean the strainer plate, if applicable, and replace the intake adapter gasket, and reinstall the adapter securely . Check line connections both at the compressor intake adapter and at the engine air cleaner. Inspect the connecting line for ruptures and replace it if necessary .

AIR LEAKAGE TESTS

Leakage past the discharge valves can be detected by removing the discharge line, applying shop air back through the discharge port and listening for escaping air. Also the discharge valves and the unloader pistons can be checked for leakage by building up the air system until the governor cuts out, then stopping the engine. With the engine stopped, carefully listen for escaping air at the intake. To pinpoint leakage if noted, squirt oil around the unloader pistons. If there is no noticeable leakage at the unloader pistons, the discharge valves may be leaking.

If the compressor does not function as described above, or leakage is excessive, it is recommended that it be returned to the nearest Bendix authorized distributor for a factory rebuilt compressor under the repair exchange plan. If this is not possible, the compressor can be repaired with genuine Bendix parts, in which case the following information should prove helpful.

REMOVING AND INSTALLING

REMOVING

These instructions are general and in some cases additional precautions must be taken. Drain air brake system. If water-cooled type compressor, drain engine cooling system, compressor cylinder head and block. Disconnect all air lines, water and oil lines to and from compressor. Remove compressor mounting bolts and compressor from engine. Use a gear-puller to remove the gear or pulley from compressor crankshaft.

INST ALLATION ENGINE-LUBRICATED TYPES

Clean oil supply line. Before connecting this line to the compressor, run the engine briefly to be sure oil is flowing freely through the supply line. Clean the oil return line or return passages through the brackets; these passages must be unrestricted so oil can return to the engine.

Prelubricate compressor cylinder walls and bearings with clean engine oil before assembling compressor. Always use a new mounting gasket and be sure oil hole in gasket and compressor is properly aligned with oil supply line.

SELF-LUBRICA TED TYPES

Fill compressor crankcase with clean engine oil before operating compressor. Refer to “Tabulated Data” section for proper amount.

ALL TYPES

Inspect pulley or gear and associated parts for wear or damage. They must be a neat fit on compressor crankshaft. Replace pulley or gear if worn or damaged. Install pulley or gear on compressor crankshaft making sure it properly contacts the shaft and does not ride the key. Tighten crankshaft nut to 65-70 ft. lbs. and install cotter pin. Be sure the air cleaner is clean and properly installed. If the compressor intake is connected to either the engine air cleaner or supercharger, these connections must be tight with no leakage. Clean or replace any damaged or dirty air or water lines which may be corroded, before connecting them to the compressor. Use a new discharge fitting gasket. Align compressor drive and adjust proper belt tension. Tighten mounting bolts securely and evenly . After installation, run compressor and check for air, oil, or water leaks at compressor connections. Also check for noisy operation.

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 P ASSING

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 action 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.

Drain the engine cooling system and the cylinder head of the compressor. Disconnect all air , water and oil lines leading to and from the compressor. Remove the drive gear(s) or pulley from the compressor crankshaft using a gear puller. Inspect the pulley or gear and associated parts for visible wear or damage. Since these parts are precision fitted, they must be replaced if they are worn or damaged.

DISASSEMBLY

GENERAL

Remove 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 both the front and rear end cover in relation to the crankcase. Mark the drive end of the crankshaft in relation to the front end cover and the crankcase. Mark the cylinder head in relation to the block and block to crankcase. Mark the base plate or base adapter in relation to the crankcase.

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 a marking method that can be wiped off or obliterated during rebuilding, such as chalk. Remove all compressor attachments such as governors, air strainers or inlet fittings, discharge fittings and pipe plugs.

CYLINDER HEAD

Remove the cylinder head cap screws and tap the head with a soft mallet to break the gasket seal. Remove the inlet valve springs form the head and inlet valves from their guides in the block. Remove inlet valve guides from around the inlet valve seats on the block, taking care not to damage seats. Scrape off any gasket material from the cylinder head and block. Unscrew the discharge cap nuts from the head and remove the discharge valves and springs. Inspect the discharge valve seats for nicks, cracks, and excessive wear and remove and replace if necessary .

The discharge valve cap nuts should be inspected for wear

and replaced if excessive peening has occurred. To determine if excessive peening has occurred, measure the discharge valve travel. Discharge valve travel must not exceed .056 in. for the Tu-Flo® 400 compressor and .046 in. for the Tu-Flo® 500 and 1000 compressors.

CRANKCASE BASE PLA TE OR ADAPTER

Remove the cap screws securing the base plate or base adapter. Tap with soft mallet to break the gasket seal. Scrape off any gasket material from crankcase and plate or adapter .

REMOVING AND DISASSEMBLY

REMOVING

These instructions are general and are intended to be a guide. In some cases additional preparations and precautions are necessary . Chock the wheels of the vehicle and drain the air pressure from all the reservoirs in the system.

CONNECTING ROD ASSEMBLIES

(NOTE: Before removing the connecting rods, mark each

connecting rod and its cap. Each connecting rod is matched to its own cap for proper bearing fit, and these parts must not be interchanged.)

FIGURE 17 - TU-FLO® 400 AIR COMPRESSOR VERTICAL MOUNT - ENGINE LUBRICATED

Straighten the prongs of the connecting rod bolt lock strap and remove the bolts and bearing caps. Push the piston with the connecting rods attached out the top of the cylinders of the crankcase. Replace the bearing caps on their respective connecting rods. Remove the piston rings from the pistons. If the pistons are to be removed from the connecting rods, remove the wrist pin lock wires or teflon plugs and press the wrist pins from the pistons and connecting rods.

If the pistons are removed from the rod, inspect the bronze wrist pin bushing. Press out and replace the bushing if it is excessively worn. (See Inspection of Parts.) Discard the piston rings and the connecting rod journal bearings. Discard the wrist pin bushings if they were removed. New Tu-Flo

FIGURE 18 - BASE PLATE SELF-LUBRICATED TYPE

COMPRESSOR

400 compressors manufactured after approximately September 1977 will have connecting rods without bearing inserts. Repair size rods will have inserts.

REMOVING AND DISASSEMBLING BASE PLATE SELF-LUBRICA TED TYPE COMPRESSORS (Fig. 18)

Remove screws that hold base plate. Remove base plate. Remove oil relief valve set screw, then oil relief valve. Remove oil strainer retaining ring and lift out oil strainer . Unless it is necessary , the oil pump piston bushing should not be removed. If necessary , remove the bushing set screw, then bushing and shim.

Remove cotter pin from oil rod cap nuts, remove nuts, oil pump piston rod and cap.

CRANKCASE (Fig. 19)

Remove end cover with oil seal, remove end cover gasket. Replace oil seal after cleaning end cover .

Remove cap screws that hold opposite end cover to crankcase; remove end cover and its gasket. Some compressors have crankcases that have a shoulder for positioning the crankshaft. In these cases the crankshaft must be removed through one particular end.

CLEANING AND INSPECTION OF PARTS

CLEANING

All parts should be cleaned thoroughly in a good cleaning solvent before inspection.

CYLINDER HEAD ASSEMBL Y

Remove all carbon deposits from discharge cavities and all rust and scale from cooling cavities of cylinder head body . Scrape all foreign matter from body surfaces and use air pressure to blow dirt particles from all cavities.

Discharge valves can be dressed by lapping them on a piece of fine crocus cloth on a flat surface, provided they are not excessively worn.

CYLINDER BLOCK

Clean carbon and dirt from inlet and unloader passages. Use air pressure to blow carbon and dirt deposits from unloader passages.

Inlet valves, as in the case of discharge valves, not worn excessively , can be cleaned by lapping them on a piece of fine crocus cloth on a flat surface.

OIL P ASSAGE

Clean thoroughly all oil passages through crankshaft, connecting rods, crankcase, end covers and base plate. If necessary , inspect p assages with a wire and blow foreign matter out with air pressure.

CRANKCASE - SELF-LUBRICA TED TYPE

The breather should be thoroughly washed and cleaned. The oil pump check valve in the base should be removed

and replaced. It is important when the oil pump check valve is replaced that it be installed correctly with the ball stop pin end pressed in first. When installed, the ball and its seat should be visible from the crankcase base.

INSPECTION OF PARTS

CYLINDER HEAD BODY

Inspect cylinder head body for cracks or damage.

WA TER-COO LED TYPE

Use air pressure to test water jackets of cylinder head and block for leakage. Replace unit if leakage is found.

DISCHARGE V AL VES AND SEA TS

If discharge valves are worn and grooved where they contact the seats, they should be replaced. If the discharge valve seats are worn excessively so that there is no longer enough metal left to reclaim them by lapping, the seats should be replaced.

DISCHARGE VA LVE SPRING AND CAP NUTS

Replace all used discharge valve springs and cap nuts.

FIGURE 20 - CYLINDER BLOCK - EXPLODED VIEW

Press the crankshaft and ball bearings from the crankcase, then press ball bearings from crankshaft. Many compressors will have sleeve-type bearings in the crankcase or in the end cover. If the clearance between crankshaft journal and bearing exceeds .0065 in. the sleeve bearing should be replaced with appropriate undersize.

BLOCK (Fig. 20)

If compressor is fitted with an air strainer, inlet elbow or governor, remove same.

Remove cap screws securing cylinder block to crankcase; separate crankcase and cylinder block and scrape off gasket.

Remove unloader spring, spring saddle and spring seat from cylinder block.

Remove unloader guides and plungers and, with the use of shop air, blow unloader pistons out of cylinder block unloader piston bores.

Remove inlet valve guides; inlet valve seats can be removed but only if they are worn or damaged and are being replaced. Unloader bore bushings should be inspected but not removed unless they are damaged.

FIGURE 19 - CRANKCASE - TU-FLO® 400 & 500 AIR COMPRESSORS

FIGURE 19A - CRANKCASE - TU-FLO® 1000 AIR COMPRESSOR

CRANKCASE AND END COVERS

Check for cracks or broken lugs in crankcase and end covers. Also check their oil passages to make sure they are open and clean.

If an oil seal ring is used in the end cover, check fit of ring in ring groove. There should be 0.008 in. to 0.015 in. clearance at the gap when placed in the end bore of the crankshaft. If the oil ring is worn thin or is damaged, it should be replaced. Inspect oil ring groove in end cover; if groove is worn excessively replace end cover or machine groove for next oversize oil seal ring.

If the crankshaft main bearings are installed in the end cover , check for excessive wear and flat spots and replace if necessary .

CYLINDER BLOCK

Check for cracks or broken lugs on cylinder block. Also check unloader bore bushings to be sure they are not worn, rusted or damaged. If these bushings are to be replaced they can be removed by running a 1/8 in. pipe thread tap inside the bushing, then inserting a 1/8 in. pipe threaded rod and pulling the bushing straight up and out. Do not use an easy-out for removing these bushings.

INLET V AL VES AND SEA TS

If inlet valves are grooved or worn where they contact the seat, they should be replaced. If the inlet valve seats are worn or damaged so they cannot be reclaimed by facing, they should be replaced.

CYLINDER BORES

Cylinder bores which are scored or out of round by more than 0.002 in. or tapered more than 0.003 in. should be rebored or honed oversize. Oversize pistons are available in

0.010, 0.020, and 0.030 oversizes. Cylinder bores must be smooth, straight and round.

Clearance between cast iron pistons and cylinder bores should be between 0.002 in. minimum and 0.004 in. maximum (Fig. 21).

PISTONS

Check pistons for scores, cracks or enlarged ring grooves; replace pistons if any of these conditions are found. Measure each piston with a micrometer in relation to the cylinder bore diameter to be sure the clearance is between 0.002 in. minimum and 0.004 in. maximum.

Check fit of wrist pins on pistons and connecting rod bushings. Wrist pin should be a light press fit in pistons. If wrist pin is loose fit, the pin, piston, or both should be replaced. Check fit of wrist pin in connecting rod bushing by rocking the piston. This clearance should not exceed 0.0015 in. Replace wrist pin bushings if excessive clearance is found. Wrist pin bushings should be reamed after being pressed into connecting rods. Replace used wrist pin lock wires. Tu-Flo® 400 compressors manufactured after September 1977 will have Teflon plugs in each end of the wrist pins instead of the lock wire. The Teflon plugs (pc. no. 292392) may be used instead of the lock wires on all compressors. See Fig. 22.

PISTON RINGS

Check fit of piston rings in piston ring grooves. Check ring gap with rings installed in cylinder bores. Refer to Fig. 24 for correct gap and groove clearance.

All rings must be located in their proper ring grooves as shown. The rings can be identified by the width and should be installed with the bevel or the pipmark (if any) toward the top of the piston. This applies to cast iron pistons (only as shown above).

Die cast pistons use five (5) narrow rings.

FIGURE 21 - MEASURING CYLINDER BORES

FIGURE 22 - TU-FLO® 400 AIR COMPRESSOR NEW STYLE

COMPRESSION

RINGS (2)

COMPRESSION

RINGS (2)

TU-FLO® 400 AIR COMPRESSOR

CORRECT GROOVE

CLEARANCE

.0015” .0030”

CORRECT GAP

CLEARANCE WITH RING

IN CYLINDER

.0035”

.014”

FIGURE 23 - TU-FLO® 400 AIR COMPRESSOR OLD STYLE

TU-FLO® 500 & 1000 AIR COMPRESSOR

CORRECT GROOVE

CLEARANCE

.0035” .0035”

CORRECT GAP

CLEARANCE WITH RING

IN CYLINDER

FIGURE 24 - PISTON RING POSITIONS - GAPS AND GROOVE CLEARANCE

.002” .004”

.0035”

.014”

NARROW

WIDE

NARROW

WIDE

UNLOADER MECHANISM

Used unloader mechanism should be replaced by unloader

kits 265014 for T ype T u-Flo

400 compressors and 265015 for T ypes Tu-Flo® 500 and 1000 compressors. The T u-Flo 1000 compressor requires two kits per compressor .

The new unloader pistons should be a loose sliding fit in the unloader piston bores of the cylinder block.

PARTS SPECIAL TO SELF-LUBRICATED TYPE COMPRESSORS

OIL PUMP SCREEN

Check oil pump screen to be sure it is clean and not damaged; replace if damaged.

OIL PUMP PISTON AND BUSHING

Check fit of oil pump piston in base plate pump bushing. It must be a medium sliding fit. If excessive clearance is found, the oil rod and/or bushing must be replaced.

OIL PUMP RELIEF V A LVE

If the oil pump relief valve is defective, it should be replaced.

OIL PUMP CHECK V AL VE

The check valve should be replaced. It can be checked by applying air pressure back through the pin stop end and noting that the ball check seals on its seat.

REPAIRS

CRANKSHAFT

Check crankshaft screw threads, keyways, tapered ends and all machined and ground surfaces for wear, scores, or damage. Crankshaft journals which are out of round more than 0.001 in. must be reground. Bearing inserts are available in 0.010 in., 0.020 in., and 0.030 in. undersizes for reground crankshafts. Main bearing journals must be maintained so bearings are snug fit. The oil seal ring groove or grooves in crankshafts fitted with oil seal rings must not be worn. The ring groove walls must have a good finish and they must be square. Check to be sure the oil passages are open and clean through the crankshaft.

CONNECTING ROD BEARINGS

Check connecting rod bearings on crankshaft journals for proper fit. Used bearing inserts should be replaced. Connecting rod caps are not interchangeable. The locking slots of the connecting rod and cap should be positioned adjacent to each other.

Clearance between the connecting rod journal and the connecting rod bearing must not be less than 0.0003 in. or more than 0.0021 in. after rebuilding.

MAIN BEARINGS

Check for wear or flat spots; if found, bearings should be replaced. If type with sleeve bearing, this bearing should be checked for scores and wear and replaced if necessary .

DISCHARGE V AL VES AND SEA TS

If discharge valve seats merely show signs of slight wear, they can be dressed by using a lapping stone, grinding compound and grinding tool. Install new discharge valves and valve springs.

T o test for leakage by the discharge valves, apply about 100 pounds of air pressure through the cylinder head discharge port and apply soap suds at the discharge valves and seats. Leakage which will permit the formation of bubbles is permissible.

If excessive leakage is found, leave the air pressure applied, and with the use of a fibre or hardwood dowel and hammer, tap the discharge valves off their seats several times. This will help the valves to seat and should reduce any leakage.

With the air pressure still applied at the discharge port of the cylinder head, check for leakage at the discharge valve cap nuts. No leakage is permissible.

INLET V AL VES AND SEA TS

If inlet valve seats show sign of slight nicks or scratches, they can be redressed with a fine piece of emery cloth or by lapping with a lapping stone, grinding compound and grinding tool. If the seats are excessively damaged to the extent that they cannot be reclaimed, they should be replaced. The dimension from the top of the cylinder block to the inlet valve seat should not exceed 0.118 in. nor be less than

0.101 in.

Slightly worn or scratched inlet valves can be reclaimed by lapping them on a piece of fine crocus cloth on a flat surface, but it is suggested that new inlet valves be installed.

ASSEMBLY

INST ALLING CYLINDER BLOCK

Position cylinder block gasket and block on crankcase according to markings made prior to disassembly. Using cap screws with lock washers, secure cylinder block to crankcase.

INST ALLING CRANKSHAFT

If the crankshaft is fitted with oil seal rings, install rings. Position ball bearings and crankshaft in crankcase, making sure the drive end of the crankshaft is positioned as marked before disassembly.

If one end of the crankcase is counterbored for holding a bearing, be sure the crankshaft is installed through the correct end of the crankcase.

Carefully press crankshaft and bearings into crankcase using arbor press.

Remove connecting bolts and bearing cap from one connecting rod. Turn crankshaft so one of its connecting rod journals is in the downward, center position. Compress the rings with a ring compression tool and insert the connecting rod with piston through the top of the cylinder whose journal is down. Position and attach the bearing cap to the connecting rod, making sure the bolt lock washers are properly positioned on the cap. Tighten connecting rod bolts evenly and bend the two new lock washer prongs up against the hex head of the bolt. Install the other connecting rod and piston in the same manner.

Position a new rear end cover gasket, when used, over the rear end of the crankcase, making sure the oil hole in the gasket lines up with the oil hole in the crankcase. Position end cover with oil seal ring, if used, installed over crankcase and end cover gasket. The end cover should be positioned correctly in relation to the oil holes in the gasket and crankcase. Secure end cover to crankcase with cap screws and lock washers.

If the opposite end cover requires an oil seal which was removed on disassembly, a new seal should be pressed into end cover. Position new end cover gasket and carefully install end cover over crankshaft and to crankcase, avoiding damage to the seal. Secure end cover with cap screw and lock washers.

PISTONS AND CONNECTING RODS

If new wrist pin bushings are to be used, they should be pressed into the connecting rods so that the oil hole in the bushing lines up with the one in the rod. The new bushings should then be reamed or honed to provide between 0.0002 in and 0.0007 in. clearance on the wrist pin. Position connecting rod in piston and press in wrist pin so that lockwire hole in the pin aligns with that of the piston. Install new lockwire through piston and wrist pin and lock same by snapping short end into lockwire hole at the bottom of the piston (Fig. 7). T eflon plugs in wrist pin ends may be used instead of the lockwires (Fig. 22).

Install piston rings in correct location with ring pipmarks up (Fig. 24). Stagger the position of the ring gap s.

Prelubricate piston, piston rings, wrist pin and connecting rod bearings with clean engine oil before installing them in the compressor.

FIGURE 25 - UNLOADER MECHANISM

UNLOADER MECHANISM (Fig. 25)

The unloader pistons and their bores must be lubricated with special lubricant piece number 239379 (dimethyl polysiloxane) prior to installation. If new unloader kits are being installed, the pistons in the kit are already lubricated.

Install the unloader pistons in their bores with caution against cutting the grommets or distorting the back-up rings. Position unloader plungers in their guides and slip them in and over the tops of the pistons.

Install the unloader spring seat in the cylinder block; a small hole is drilled in the block for this purpose. Position the saddle between unloader piston guides so its forks are centered on the guides. Install the unloader spring, making sure it seats over the spring seats both in the block and on the saddle.

Install inlet valve seats if they have been previously removed. Position and install inlet valve guides, then drop inlet valves in their guides. There should be a loose sliding fit between guides and valves.

CYLINDER HEAD ASSEMBL Y

If previously removed, the discharge valve seats should be installed. Drop discharge valves into their seats. Install discharge valve springs and cap nuts.

Place the inlet valve springs in the cylinder head. Use a small quantity of grease to hold them in place, just enough grease to keep the springs from falling out. Place cylinder head gasket on cylinder block. Carefully align cylinder head assembly on block and install cap screws with lock washers. Tighten securely and evenly cap screws that hold cylinder head to block.

BASEPLATE

SELF-LUBRICATED TYPE COMPRESSORS

Install oil pump piston and rod on crankshaft. Oil rod bearing fit must be the same as specified for

connecting rod bearings. Install oil rod cap nuts and cotter pins to lock oil rod nuts.

Install oil pump relief valve in base plate. The relief valve can be tested at this stage by applying air pressure to the relief valve. The valve should open when the pressure is between 14 psi minimum and 24 psi maximum. When the relief valve is properly installed in the base plate, install set screw that locks it in place.

Place oil pump screen in base and install retaining ring, making sure it snaps in place and secures the screw .

Install oil filter fitting on base plate in its proper place. Install blanking cover on opposite oil filter fitting hole in plate.

Install a new oil seal gasket around oil pump - check valve and position a new base plate gasket on the crankcase. Position base plate assembly on crankcase, making sure oil pump piston engages the oil pump bushing in the base plate. Install and tighten base plate screws.

TESTING REBUIL T 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 efficiency or build-up test can be run which is not too difficult. Before the test, the crankcase of a selflubricated type compressor should be properly filled with lubricating oil. An engine lubricated compressor must be connected to an oil supply line of at least 15 pounds pressure during the test and an oil return line must be installed to keep the crankcase drained. The compressor (when tested) should be tested without a strainer.

T o the discharge port of the compressor , connect a reservoir or reservoirs whose volume plus the volume of the connecting line equals 1,300 cubic inches. Run the compressor between 1,700 and 1,750 RPM. Elapsed time that the compressor takes to build up from 0 to 100 psi depends on the type compressor as follows:

BUILD-UP TIME

TYPE COMPRESSOR 0 TO 100 PSI

TU-FLO TU-FLO

TU-FLO

400 47 SECONDS MAXIMUM

500 30 SECONDS MAXIMUM

1000 15 SECONDS MAXIMUM

During the above test the compressor should be checked for oil leakage and noisy operation.

FIGURE 26 - AIR STRAINER - EXPLODED VIEW

AIR STRAINER

If the compressor is type with air strainer, assemble strainer (Fig. 26). Using a new strainer gasket, install strainer on cylinder block.

GOVERNOR

If compressor is type with pad mounted governor , install a new or factory rebuilt governor using a new governor gasket.

INSPECTION OF REBUIL T UNIT

Check to be sure that covers, plugs or masking tape are used to protect all ports if compressor is not to be installed immediately.

Fit the end of all crankshafts with keys, nuts and cotter pins as required and then protect the ends against damage by wrapping with masking or friction tape.

The open bottom of engine lubricated compressors should be protected against the entrance of dirt during handling or storage, by installing a temporary cover over base.

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.

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.

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 an AD-

™

air dryer system or 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.

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, fittings, etc. must be of equivalent size, type and strength as original equipment and be designed specifically 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 Antilock 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.

MAINTENANCE INSTRUCTIONS FOR LARGE SUMP TU-FLO® 1000 AIR COMPRESSOR 288578 (SPECIAL APPLICATION)

This compressor is an air-cooled, belt driven, self lubricated, V-four cylinder compressor . It is driven by an electric motor and cooling air is supplied by a fan on the driven pulley . The system air pressure is controlled between 135 psi and 150 psi by a pressure switch starting and stopping the electric motor.

INSTALLATION

The base mounted compressor should be securely bolted down with 1/2" grade five or better cap screws torqued to 70 ft. pounds, making sure that motor and compressor pulleys are aligned and belt tension is correct. The crankcase should be filled with five quarts (4.7 liter) of SAE 20 W engine oil. The compressor must always be installed to rotate clockwise when viewed from the pulley end. The oil pump will not function if rotation is not correct.

SCHEDULED MAINTENANCE

NOTE: When checking or adding oil or servicing the

crankcase breather, care should be t aken to prevent dirt or foreign material from entering the breather or oil sump.

Every 7,500 miles or seven weeks, whichever occurs first: Check oil level - replenish to top of filler plug opening. Replace both air cleaner filter elements and clean covers. Check belts and replace if broken, damaged or missing.

Every 15,000 miles or 14 weeks, whichever occurs first: Remove crankcase ventilator, clean port s and replace with freshly oiled curled hair.

Every 22,500 miles or 21 weeks, whichever occurs first: Drain oil and refill with fresh SAE 20 W engine oil. Inspect all bolts, fittings and plugs to ensure that all are tight.

TABULATED DATA

TU-FLO® 400 TU-FLO® 500 TU-FLO® 1000

Number Cylinders 2 2 4 Bore Size 2.0625" 2.5" 2.5" Stroke 1.5" 1.6875" 1.6875"

Displacement at 1,250 RPM 7.25 cu. ft./min. 12 cu. ft./min. 24 cu. ft./min.

Maximum recommended RPM 3,000 water cooled 3,000 water cooled 3,000 water cooled Minimum coolant flow at 2.5 gal./min. 2.5 gal./min. 2.5 gal./ min.

maximum RPM water cooled water cooled water cooled

Approximate horsepower required

at 1,250 RPM 1.2 H.P. 2.3 H.P. 4.6 H.P. Maximum inlet air temperature 250° F. 250° F. 250° F. Maximum discharge air temperature 400° F. 400° F. 400° F. Minimum pressure required

to unload 60 PSI 60 PSI 60 PSI Minimum oil pressure required at

engine idling speed 5 P SI 5 PSI 5 PSI Minimum oil pressure required at

maximum governed engine speed 15 PSI 15 PSI 15 PSI Approximate average weight 34 lbs. 46 lbs. 75 lbs. Oil capacity of self-lubricated model .53 qts. .53 qts. .95 qts. to 5 qts.* Minimum discharge line size 1/2" O.D. tubing 5/8" O.D. tubing 5/8" O.D. tubing or equivalent

Minimum coolant line size 3/8" O.D. tubing 1/2" O.D. tubing 1/2" O.D. tubing Minimum oil supply line size 1/4" O.D. tubing 1/4" O.D. tubing 1/4" O.D. tubing Minimum oil return line size 1/2" O.D. tubing 5/8" O.D. tubing 5/8" O.D. tubing **Minimum air inlet line size 5/8" I.D. 5/8" I.D. 1" I.D. if equipped with inlet

*Part Number dictates oil capacity **Inlet line sizes specified for compressors with inlet connected to engine manifold.

Air Compressor Air Compressor Air Compressor

2,400 air cooled 2,400 air cooled 2,400 air cooled

250 CFM air flow 250 CFM air flow 250 CFM air flow

or equivalent or equivalent from each head to a common

or equivalent or equivalent or equivalent or equivalent or equivalent or equivalent or equivalent or equivalent or equivalent

manifold with 1" tubing from

manifold; or, dual 5/8" I.D. lines

from engine to compressor inlets.

manifold.

*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) . . . . . . . . . . . . . . . . . 24 - 25

Doesn’t build air (10.0) . . . . . . . . . . . . . . . 26

Air dryer:

Doesn’t purge (14.0) . . . . . . . . . . . . . . . . . 27

Safety valve releases air (12.0). . . . . . . . . 27

Compressor:

Constantly cycles (15.0) . . . . . . . . . . . . . . 27

Leaks air (16.0) . . . . . . . . . . . . . . . . . . . . . 28

Safety valve releases air (11.0). . . . . . . . . 26

Noisy (18.0) . . . . . . . . . . . . . . . . . . . . . . . . 28

Reservoir:

Safety valve releases air (13.0). . . . . . . . . 27

INDEX

Air

Coolant

Engine

Oil

Compressor leaks coolant (17.0) . . . . . . . . . . 28

Oil consumption (6.0) . . . . . . . . . . . . . . . . . . . 24

Oil Test Card results (1.0) . . . . . . . . . . . . . . . . 19

Oil is present:

On the outside of the compressor (2.0). . . 20 At the air dryer purge/exhaust

or surrounding area (3.0) . . . . . . . . . . . 20

In the supply reservoir (4.0). . . . . . . . 21 - 23

At the valves (5.0) . . . . . . . . . . . . . . . . . . . 23

At air dryer cartridge (7.0) . . . . . . . . . . . . . 24

In the ping tank or compressor

discharge aftercooler (8.0) . . . . . . . . . . 24

Symptom Page Number

(1) Oil Leakage at Head Gasket . . .29

(2) System Leakage . . . . . . . . . . . . 2 9

(3) Compressor Discharge and

Air Dryer Inlet Temperature . . . . 29

(4) Governor Malfunction . . . . . . . .30

(5) Governor Control Line . . . . . . . .30

(6) Compressor Unloader . . . . . . . . 30

BASIC Test Information . . . . . . 3 2-34

Test Procedures

Maintenance Schedule and Usage Guidelines (Table A) . . 1 8

Symptom Page Number

Maintenance & Usage Guidelines

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 fittings, 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 18) 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 fitting to avoid low points where ice may 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 degree fitting, it may be changed to a straight or 45 degree fitting. For more information on how to help prevent discharge line freeze-ups, see Bendix Bulletins TCH-08-21 and TCH-08-22 (see pages 35-37). Shorter discharge line lengths or insulation may be required in cold climates.

For vehicles with accessories that are sensitive to small amounts of oil, we recommended installation of a Bendix® PuraGuard® system filter, designed to minimize the amount of oil present.

Air Dryer

Reservoir Drain

Service Reservoir

(Supply Reservoir)

Compressor

Governor

(Governor plus Synchro valve

for the Bendix

DuraFlo™ 596

™

Compressor)

Discharge Line

Optional “Ping” Tank

Optional Bendix® PuraGuard

System Filter or PuraGuard

QC™ Oil Coalescing Filter

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.

Table A: Maintenance Schedule and Usage Guidelines

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

Vehicle Used for:

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

e.g. Line haul single trailer

with air suspension,

school bus.

High Air Use

Compressor with up to 25% duty cycle

e.g. Double/triple trailer, open

highway coach/RV, (most)

pick-up & delivery, yard or

terminal jockey, of f-highway ,

construction, loggers, concrete

mixer, dump truck, fire truck.

Compressor with up to 25% duty cycle

e.g. City transit bus, refuse,

bulk unloaders, low boys,

urban region coach, central

tire inflation.

Column 1

Typical Discharge mended mended Reservoir

No. of Spec'd Cartridge Drain at Regular

Axles Replacement

Compressors Line Air Dryer Reservoir Oil Contents

less

550 air compressor

less

Tu-Flo

air compressor

™

Bendix

BA-921

Bendix

less

750 air compressor

Tu-Flo

air compressor

Bendix

596

™

, or DuraFlo

™

less

BA-922

Column 2 Column 3 Column 4 Column 5

Recom- Recom- Acceptable

I.D.

1/2 in.

For oil carry-over

control

Length

6 ft.

suggested

upgrades:

5/8 in. 9 ft.

9 ft.1/2 in.

For oil carry-over

control

suggested

upgrades:

Every 3

Years

Schedule2Drain Interval

Recommended

Every

Month -

Max of

every 90

days

5/8 in. 12 ft.

1/2 in.

12 ft.

Every 2

For oil carry-over

control

suggested

upgrades:

5/8 in. 15 ft.

Years

BASIC test acceptable

5/8 in.

Every

Month

12 ft.

per month.

Every

For oil carry-over

control

suggested

upgrades:

Year

3/4 in. 15 ft.

BASIC test acceptable

range:

3 oil units

per month.

See

appendix

For the BASIC

Test Kit:

Order

Bendix

P/N

5013711

range:

5 oil units

See

appendix

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 sufficient cooling occurs, the oil-vapor condenses and can be removed by the air dryer. Discharge line upgrades are not covered under warranty. Note: T o help prevent discharge line freeze-ups, shorter discharge line lengths or insulation may be required in cold climates. (See Bendix Bulletins TCH-08-21 and TCH-08-22, 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.

Note: Compressor and/or air dryer upgrades are recommended in cases where duty cycle is greater than the normal range (for the examples above).

For Bendix compressors, unloader service is

recommended every 250,000 miles.

Tu-Flo® 550 and 750

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.

Look for:

Normal - Charging system is working within normal range.

Check - Charging system needs further investigation.

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.

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.

™

air dryer system or a dryer

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 and kits. Replacement hardware, tubing, hose, fittings, etc. must be of equivalent size, type and strength as original equipment and be designed specifically for such applications and systems.

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 Antilock 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.

replacement parts, components

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® BASIC test should be the definitive method for judging excessive oil fouling/oil passing. (See Appendix A, on

page 32 for a flowchart and expanded explanation of the checklist used when conducting the BASIC test.)

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

2.2 Oil leaking from compressor:

(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.)

ð Go to Test 1 on page 29. ð Reseal bottom cover plate using RTV

silicone sealant.

ð Replace compressor. ð Replace compressor. ð Clean compressor and check periodically.

Air brake charging system functioning normally.

ð 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.

3.0 Oil at air dryer purge/exhaust or surrounding area

(c)

2.0 Oil on the Outside of the Compressor

Find the source and repair. Return the vehicle to service.

ð Repair or replace as necessary. If the

mounting bolt torques are low, replace the gasket.

ð Replace the fitting gasket. Inspect inlet

hose and replace as necessary.

ð Replace gasket or fitting as necessary to

ensure good seal.

ð Inspect and repair as necessary.

Engine and/or other accessories leaking onto compressor.

(a)Leak at the front or rear (fuel

pump, etc.) mounting flange.

(b)Leak at air inlet fitting.

(c)Leak at air discharge fitting.

(d)Loose/broken oil line fittings.

2.1 Oil leaking at compressor / engine connections:

(a)

Head gasket and rear flange gasket locations.

(c)

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

(If a maintained Bendix

PuraGuard® system filter or Bendix

PuraGuard

QC™ oil coalescing filter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.)

(a)If air brake charging system

maintenance has not been

performed.

That is, reservoir(s) have not been drained per the schedule in Table A on p age 18, 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 18, some oil in the reservoirs is normal.

ð Drain all air tanks and check vehicle at next

service interval using the Bendix

BASIC test. See Table A on page 18, column 3 and 4, for recommended service schedule.

ð 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 (T est 2, on page 29), 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. ðIf 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 filter. ð If outside the normal range go to Symptom 4.0(c). Also see the Table A on page 18, column 3 for recommended air dryer cartridge replacement schedule.

Maintenance

(a)

ð Go to

Test 2 on page 29.

ð See Table A, column 1, on page 18 for

recommended compressor sizes. ð 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. ð If the compressor is correct for the vehicle, go to Symptom 4.0 (e).

Duty cycle too high

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

See Table A, on page 18, for maintenance schedule information.

Drain

all air tanks (reservoirs) into the Bendix® BASIC test cup. (Bendix kit P/N 5013711).

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 stop s, excessive leakage from fittings, connections, lines, chambers or valves, etc.

(c)Air brake system leakage. (d)Compressor may be undersized for

the application.

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

(e) Air compressor discharge and/or

air dryer inlet temperature too high.

(f) Insufficient coolant flow.

(g) Restricted discharge line.

ð Check temperature as outlined in Test 3

on page 29. If temperatures are normal go to 4.0(h).

ð Inspect coolant line. Replace as necessary

(I.D. is 1/2").

ð Inspect the coolant lines for kinks and

restrictions and fittings for restrictions. Replace as necessary.

ð Verify coolant lines go from engine block

to compressor and back to the water pump. Repair as necessary.

ð 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 18 for recommended size. Replace as necessary.

ð The discharge line must maintain a

constant slope down from the compressor to the air dryer inlet fitting to avoid low points where ice may 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 degree fitting, it may be changed to a straight or 45 degree fitting. For more information on how to help prevent discharge line freeze-ups, see Bendix Bulletins TCH-08-21 and TCH-08-22 (Appendix B). Shorter discharge line lengths or insulation may be required in cold climates.

Temperature

Other

ð Check compressor air inlet line for

restrictions, 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.

ð Check the engine air filter and service if

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

(h)Restricted air inlet (not enough air

to compressor).

(g)

(h)

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

(f)

(e)

(g)

Kinked discharge line shown.

Partly collapsed inlet line shown.

Testing the temperature at the discharge fitting.

Inspecting the coolant hoses.

*If a maintained Bendix

PuraGuard® system filter or Bendix® PuraGuard® QC™ oil coalescing filter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.

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

(i) Poorly filtered inlet air (poor air

quality to compressor).

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

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

(continued)

ð 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.

ð Go to Test 4 on page 30. ð If you found excessive oil present in the

service reservoir in step 4.0 (b) above and you did not find 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 flushed from the air brake system.

Other (cont.)

Inspect the engine air cleaner.

** SAE J2024 outlines 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 brake system valves are required to tolerate a light coating of oil.

ð A small amount of oil does not affect SAE

J2024** compliant valves.

ð 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 18). Return the vehicle to service.

For oil-sensitive systems, see page 17.

Genuine Bendix valves are all SAE J2024 compliant.

*If a maintained Bendix

PuraGuard® system filter or Bendix® PuraGuard® QC™ oil coalescing filter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.

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.

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.

ð See engine service manual.

ð 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 T est (see also column 5 of Table A on page 18). Replace the air dryer cartridge as needed and return the vehicle to service.

ð Follow vehicle O.E. maintenance

recommendation for these components.

ð 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.

ð Go to Test 2 on page 29. ð See Table A, column 1, on page 18 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.

ð Go to Test 6 on page 30.

ð An air leak 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 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 charging system seems slow to build pressure. (continued)

Dash gauges.

(f) Restricted discharge line.

(f)

Kinked discharge line shown.

ð If discharge line is restricted:

ð By more than 1/16" carbon build up, replace the discharge line (see Table A, column 2, on page 18 for recommended size) and go to Test 3 on page 29. ð By other restrictions (e.g. kinks). Replace the discharge line. See Table A, column 2, on page 18 for recommended size. Retest for air build. Return vehicle to service or, if problem persist s, go to 9.0(a).

ð 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.

ð Check compressor air inlet line for

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

ð Check the engine air filter and service if

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

ð Check for leaking, damaged or defective

ð 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.

ð Go to Test 4 on page 30. ð See 9.0(f). ð Replace air dryer heater.

ð Replace the compressor only after making

certain the preceding conditions do not exist.

ð If discharge line is restricted:

ð The discharge line must maintain a

constant slope down from the compressor to the air dryer inlet fitting to avoid low points where ice may 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 degree fitting, it may be changed to a straight or 45 degree fitting. For more information on how to help prevent discharge line freeze-ups, see Bendix Bulletins TCH08-21 and TCH-08-22 (Appendix B). Shorter discharge line lengths or insulation may be required in cold climates.

(b)Downstream air brake system

check valves or lines may be blocked or damaged.

(c)Air dryer lines incorrectly installed.

(d) Compressor safety valve

malfunction.

(e) Compressor unloader mechanism

malfunction.

(f) Governor malfunction.

ð Inspect air lines and verify check valves

are operating properly.

ð Ensure discharge line is installed into the

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

ð Verify relief pressure is 250 psi. Replace

if defective.

ð Go to Test 6 on page 30.

ð Go to Test 4 on page 30.

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.

(c)Air dryer maintenance not

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.

ð Inspect delivery lines to reservoir for

restrictions and repair as needed.

ð Verify relief pressure is at vehicle or

component manufacturer specifications. Replace if defective.

ð See Maintenance Schedule and Usage

Guidelines (Table A, column 3, on page

18).

ð Verify operation of air dryer. Follow vehicle

O.E. maintenance recommendations and component Service Data information.

ð Go to Test 5 on page 30.

ð Go to Test 4 on page 30.

ð Verify relief pressure is at vehicle or

component manufacturer's specifications (typically 150 psi). Replace if defective.

ð Go to Test 4 on page 30.

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.)

(c)Compressor unloader mechanism

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.

ð Go to Test 6 on page 30.

ð V erify operation of air dryer . Follow vehicle

O.E. maintenance recommendations.

ð Go to Test 4 on page 30. ð Go to Test 2 on page 29. ð Go to Test 5 on page 30.

ð Available reservoir capacity may be

reduced by build up of water etc. Drain and perform routine maintenance per Table A, columns 3 & 4, on page 18.

ð Go to Test 6 on page 30.

ð Verify operation of air dryer. Follow vehicle

O.E. maintenance recommendations and component Service Data information.

(d)Air brake system leakage.

ð Go to Test 2 on page 29.

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.

(c)Damaged compressor head

gasket.

Head

gasket

location

(a)Improperly installed plugs or

coolant line fittings.

ð Check for leaking, damaged or defective

compressor fittings, gaskets, etc. Repair

or replace as necessary.

ð Go to Test 6 on page 30.

ð An air leak 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 then replace the compressor .

Do not re-use the safety valve without

testing. See Symptom 12.0(a).

ð Inspect for loose or over-torqued fittings.

Reseal and tighten loose fittings and plugs as necessary. If overtorqued fittings 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.

(c)Porous compressor head casting.

(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.

ð 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).

ð If casting porosity is detected, replace the

compressor.

ð 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

five (5) minutes.

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, rep air the leaks and repeat this test to confirm 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 fittings:

ð at the compressor discharge port. (T1). ð at the air dryer inlet fitting. (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.

Action

Discharge Line

over __ Compressor is running hot.

360°F Check coolant 4(f) and/or

discharge line 4(g).

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

Test 5: Governor Control Line

reservoir, service reservoir, or reservoir port of the D-2™ governor, verify cut-in and cutout pressures are within vehicle OEM specification.

3. If the governor is malfunctioning, replace it.

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 fitting to the unloader port. Add a section of air hose (min 1ft long for a 1/2" diameter line) and a gauge to the fitting followed by a shut-off valve and an air source (shop air or small air tank). Open the shut

2. Perform proper reservoir drain intervals and air dryer cartridge maintenance per Maintenance Schedule and Usage Guidelines (Table A on page 18).

3. Return the vehicle to service.

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.

NOTES

Appendix A: Information about the BASIC Test Kit (Bendix P/N 501371 1)

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

drained - and f

checklist. Technician inspects items.

START BASIC TEST

Park vehicle on ground.LEVEL

Chock wheels, drain air from system.

days

Bendix® Air System Inspection Cup

(BASIC) T est 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

lineonthe

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

lineonthe

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**

UseTest2: 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).

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

Return vehicle to

END TEST

Vehicle OK.

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.

*** 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-008-21 and TCH-008-22 (included on pages 35-37 of this document).

****Note: After replacing a compressor, residual oil may take a considerable period of time to be flushed 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® Air System Inspection Cup (BASIC) Test

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

The Service Writer fills out these fields 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: ____________________

Checklist for Technician

Customer’s Complaint Have you confirmed complaint? (Please check all that apply)

“Relay valve q leaks oil / q malfunctions” . . . . . . . q no q yes*

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

“Dash valve q leaks oil / q malfunctions” . . . . . . . q no q yes*

q “Air dryer leaks oil” . . . . . . . . . . . . . . . . . . . . . . . q no q yes*

q “Governor malfunction” . . . . . . . . . . . . . . . . . . . . q no q yes*

q “Oil in gladhands” . . . . . . . . . . . . . . . . . . . . . . . . q no q yes*

how much oil did you find? ________________________________

q “Oil on ground or vehicle exterior” . . . . . . . . . . . q no q yes*

amount described: ______________________________________ q “Short air dryer cartridge life”

replaces every: ______________ q miles, q kms, or q months

q “Oil in air tanks” amount described:_______________________

We will measure amount currently found when we get to step B of the test.

q “Excessive engine oil loss” amount described: ______________

Is the engine leaking oil? . . . . . . . . . . . . . . . . . . . . . q no q yes*

Is the compressor leaking oil? . . . . . . . . . . . . . . . . . q no q yes*

q Other complaint: ______________________________________ q No customer complaint.

The Technician checks boxes for any of the complaints that can be confirmed.

Note: A confirmed com-

plaint above does NOT mean

that the compressor must be

replaced.

The full BASIC test below will

investigate the facts.

BASIC test starts here:

STEP A - Select one:

q This is a low air use vehicle: Line haul (single trailer) with 5 or less axles, or q This is a high air use vehicle: Garbage truck, transit bus, bulk unloader, or

line haul with 6 or more axles.

Then go to Step B.

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), (c) STOP the inspection, and check the vehicle

again after 30 days - see Footnote 2.

STOP + CK.

Oil

Units

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-008-21 and TCH-008-22 (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® Air System Inspection Cup (BASIC) Test

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

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).

1. Record days since air tanks were last drained.

_________ days _________ units

If number of days is:

30-60 days (high air

use) or

30-90 days (low air use)

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

Otherwise . . .

limits above)

2. Record amount

if oil level is at or below

acceptance line for number

of daysè

if oil level is above

acceptance line for number

of days è

if oil level is at or below

30-day acceptance line è

if oil level is above 30-day

acceptance line è

Acceptance

BASIC Test Example

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 we 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 confirm 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

T echnical Bulletin

Bulletin No.: TCH-008-021 Effective Date: 11/1/92 Page: 1 of 2

Subject: Air Brake System - Cold Weather Operation Tips

As the cold weather approaches, operators and fleets alike begin to look to their vehicles with an eye toward “winterization”, and particularly what can be done to guard against air system freeze-up. Here are some basic “Tips” for operation in the cold weather.

Engine Idling Avoid idling the engine for long periods of time! In addition to the fact that most engine

manufacturers warn that long idle times are detrimental to engine life, winter idling is a big factor in compressor discharge line freeze-up. Discharge line freeze-ups account for a significant number of compressor failures each year. The discharge line recommendations under “Discharge Lines” are important for all vehicles but are especially so when some periods of extended engine idling can not be avoided.

Discharge Lines

The discharge line should slope downward form the compressor discharge port without forming water traps, kinks, or restrictions. Cross-overs from one side of the frame rail to the other, if required, should occur as close as possible to the compressor. Fitting extensions must be avoided. Recommended discharge line lengths and inside diameters are dependent on the vehicle application and are as follows.

Typical P&D, School Bus and Line Haul

The maximum discharge line length is 16 feet. Length I.D. Min. Other Requirements

6.0-9.5 ft. ½ in. None

9.5-12 ft. ½ in. Last 3 feet, including fitting at the end of the discharge line, must be insulated with ½ inch thick closed cell polyethylene pipe insulation.

12-16 ft. 5/8 in. Last 3 feet, including fitting at the end of the

discharge line, must be insulated with ½ inch thick closed cell polyethylene pipe insulation.

If the discharge line length must be less than 6 feet or greater than 16 feet, contact your local Bendix representative.

Appendix B: Continued

Bulletin No.: TCH-008-021 Effective Date: 11/1/92 Page: 2 of 2

High Duty Cycle Vehicles (City Transit Coaches, Refuse Haulers, Etc.)

The maximum discharge line length is 16 feet. Length I.D. min. Other Requirements

10-16 ft. ½ in. None If the discharge line length must be less than 10 feet or greater than 16 feet, contact your local Bendix representative.

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 more moisture into the brake system.

Reservoir Draining (System Without Air Dryer)

Routine reservoir draining is the most basic step (although not completely effective) 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 . 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 DV-2™ Automatic Drain Valves). It should be noted that, while the need for daily reservoir draining is eliminated 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 consumption for a few days (Reference Service Data Sheet SD-08-2301 for the Bendix Alcohol Evaporator). Too little means the system is not receiving adequate protection and too much simply wastes alcohol. As a general guide, these systems should consume approximately 1 to 2 ounces of alcohol per hour of compressor loaded time (compressing air). City pick-up and delivery vehicles will operate with the compressors loaded (compressing air) more while compressors on highway vehicles will be loaded less. These figures are approximate and assume that air system leakage is within the limits of the Bendix “Dual System Air Brake Test and Check List” (BW1279). Last but not least, begin using alcohol several weeks prior to freezing weather to ensure that the system is completely protected. Use only methanol alcohol, such as Bendix “Air Guard”, in evaporators or injectors.

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.

AD-9™ Air Dryer Service Data Sheet SD-08-2412 AD-4™ Air Dryer Service Data Sheet SD-08-2407 AD-2™ Air Dryer Service Data Sheet SD-08-2403 AD-IP™ Air Dryer Service Data Sheet SD-08-2414 AD-SP™ Air Dryer Service Data Sheet SD-08-2415 Trailer System-Guard™ Air Dryer Service Data Sheet SD-08-2416

Appendix B: Continued

T echnical Bulletin

Bulletin No.: TCH-008-022 Effective Date: 1/1/1994 Page: 1 of 1

Subject: Additional Cold Weather Operation Tip s 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 flame 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) fluids into air brake lines or hose couplings (“glad hands”). Some fluids 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.

38 39

BENDIX TU-FLO 400, TU-FLO 500, TU-FLO 1000 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual