Tf 500 Compressor Service

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TU-FLO 400 TU-FLO 500

TU-FLO 1000

TU-FLO 400, 500, 1000 AIR COMPRESSORS *Formerly SD-01-2

SD-0

1-32

6

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DESCRIPTION AND OPERATION

GENERALThe function of the air compressor is to build up and maintainthe air pressure required to operate air powered devices inair brake or air auxiliary systems.

DESCRIPTIONTu-Flo Type 400, 500, and 1000 compressors are singlestage, reciprocating piston type compressors. Tu-Flo 400(Fig. 1) and 500 (Fig. 2) compressors have two cylinderswhile the Tu-Flo 1000 (Fig. 3) is a V-type design having fourcylinders. The rated capacity of all Bendix compressors istheir piston displacement in cubic feet per minute whenoperating at 1,250 RPM. The rated capacity of the Tu-Flo400 compressor is 7-1/4 cubic feet per minute. The Tu-Flo500 is rated at 12 cubic feet per minute and the Tu-Flo 1000has 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

and they have no external moving parts. Both air and watercooled type compressors are available. Various mountingand drive adaptations are used as required by different vehicleengine designs (Fig. 4).

Compressors are either engine or self-lubricated. Themajority used are the engine lubricated types (Fig. 5) whichobtain the oil necessary to lubricate their moving parts fromthe engines on which they are mounted. To meet therequirements of some manufacturers and for fieldinstallations, self-lubricated types (Fig. 6) are available. Theyare compressors having a self-contained oil supply andpumping system.

The method of lubricating the moving parts of the compressoris the same in either type. Oil is forced through the oilpassage in the crankshaft and out around each connectingrod journal. The turning motion of the crankshaft throws theoil that is forced out at the journals, against the cylinderbores and crankcase walls, lubricating the bores andcrankshaft bearings.

The wrist pins and wrist pin bushings are lubricated in twoways depending upon the type connecting rods used. Olderdesign compressors had forged steel rifle-drilled rods throughwhich oil was forced to the wrist pin bushings. Later versions

FIGURE 2 - TU-FLO 500



FIGURE 4 - VARIOUS COMPRESSOR MOUNTINGS

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had either die cast aluminum, cast ductile iron, or forgedsteel rods which were not rifle drilled but were drilled at thetop of the rod. The wrist pins and bushings are lubricatedby oil dripping from a drip-boss on the piston into a�catch-funnel� at the top of the rod and through the drilledpassage to the bushings and pins. (SEE FIG. 7)

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 newcompressor, whereas a nameplate with a red backgrounddesignates that the compressor is a factory reconditionedunit. All compressors are identified by the piece numberwhich is the number to use when reference is made to aparticular compressor. The type and serial number issupplementary information.

OPERATION

GENERALAll 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 orunloading the compressor in conjunction with its unloadingmechanism. This is done when the air pressure in the systemreaches the desired maximum or minimum pressures.

INTAKE AND COMPRESSION (Loaded)During the down stroke of the piston, a slight vacuum createdabove 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). Asthe piston starts its upward stroke, the air that was drawn inon the down stroke is being compressed. Now, air pressureon top of the inlet valve plus the force of its spring, returnsthe inlet valve to its seat. The piston continues the upwardstroke and compresses the air sufficiently to overcome thedischarge valve spring and unseat the discharge valve. Thecompressed air then flows by the open discharge valve, intothe discharge line and on to the reservoirs (Fig. 10).

FIGURE 5ENGINE LUBRICATED TYPE

FIGURE 6SELF-LUBRICATED TYPE

FIGURE 9

FIGURE 10

DISCHARGEVALVE

PISTON

STROKE

TO GOVERNOR

INTAKESTRAINER

UNLOADER PLUNGERINLET VALVE

TO RESERVOIR

INTAKE

DISCHARGEVALVE

PISTON

STROKE

TO GOVERNOR

INTAKESTRAINER

UNLOADER PLUNGERINLET VALVE

TO RESERVOIR

COMPRESSIONFIGURE 8 - COMPRESSOR NAMEPLATE

FIGURE 7- PISTONS & CONNECTING RODS

NEW DESIGN

WRIST PINBUSHING

�CATCH FUNNEL�

DIE CASTPISTON

DIE CASTCONNECTING ROD

OLD DESIGN

OILPASSAGE

WRIST PIN

WRIST PINBUSHING

PISTON WRIST PINLOCK WIRE

CAST IRONPISTON

STEELCONNECTING

ROD

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

NON-COMPRESSION (Unloaded)When the air pressure in the reservoir reaches the highpressure setting of the governor, the governor opens, allowingair to pass from the reservoir through the governor and intothe cavity beneath the unloader pistons. This lifts theunloader pistons and plungers. The plungers move up andhold the inlet valves off their seats (Fig. 11 ).

With the inlet valves held off their seats by the unloaderpistons and plungers, air is merely pumped back and forthbetween the two cylinders. When air is used from thereservoir and the pressure drops to the low pressure settingof the governor, the governor closes, and in doing so,exhausts the air from beneath the unloader pistons. Theunloader saddle spring forces the saddle, pistons andplungers down and the inlet valves return to their seats.Compression is then resumed.

COOLINGTu-Flo 400, 500 or 1000 compressors may be air-cooled orwater- cooled and in some instances will have air-cooledblocks and water-cooled heads. The air-cooled versionsare easily recognized by the external fins. The water-cooledversions are cooled by vehicle coolant.

PREVENTIVE MAINTENANCEIf the compressor is a self-lubricated type, it�s oil level shouldbe checked daily. The oil level should be kept between thebottom of the dipstick threads and the bottom of the dipstick(Fig. 12). Every 8,000 miles or 300 operating hours, the oilshould be drained and refilled with SAE 10-20-30.

POLYURETHANE SPONGE STRAINER (Fig. 13)Remove and wash all of the parts. The strainer elementshould be cleaned or replaced. If the element is cleaned, itshould be washed in a commercial solvent or a detergentand water solution. The element should be saturated inclean engine oil, then squeezed dry before replacing it inthe strainer. Be sure to replace the air strainer gasket if theentire air strainer is removed from the compressor intake.

FIGURE 13 - POLYURETHANE SPONGE STRAINER

FIGURE 14DRY ELEMENT- PLEATED PAPER AIR STRAINER

FIGURE 12OIL LEVEL - SELF-LUBRICATED COMPRESSOR

FIGURE 11

DISCHARGEVALVE

PISTON

STROKE

TO GOVERNOR

INTAKESTRAINER

UNLOADERPLUNGER

INLET VALVETO RESERVOIR

UNLOADING

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DRY ELEMENT - PLEATED PAPER AIRSTRAINER (FIG. 14)Remove the spring clips from either side of mounting baffleand remove the cover. Replace the pleated paper filter andremount the cleaned cover making sure the filter is inposition. Be sure to replace the air strainer gasket if theentire air strainer is removed from the compressor intake.(NOTE: Some compressors are fitted with compressor intakeadapters (Fig. 15) which allow the compressor intake to beconnected to the engine air cleaner.) In this case, thecompressor receives a supply of clean air from the engineair cleaner. When the engine air filter is changed, thecompressor intake adapter should be checked. If it is loose,remove the intake adapter, clean the strainer plate, ifapplicable, and replace the intake adapter gasket, andreinstall the adapter securely. Check line connections bothat the compressor intake adapter and at the engine aircleaner. Inspect the connecting line for ruptures and replaceit if necessary.

AIR LEAKAGE TESTSLeakage past the discharge valves can be detected byremoving the discharge line, applying shop air back throughthe discharge port and listening for escaping air. Also thedischarge valves and the unloader pistons can be checkedfor leakage by building up the air system until the governorcuts out, then stopping the engine. With the engine stopped,carefully listen for escaping air at the intake. To pinpointleakage if noted, squirt oil around the unloader pistons. Ifthere is no noticeable leakage at the unloader pistons, thedischarge valves may be leaking.

If the compressor does not function as described above, orleakage is excessive, it is recommended that it be returnedto the nearest Bendix authorized distributor for a factoryrebuilt compressor under the repair exchange plan. If this isnot possible, the compressor can be repaired with genuineBendix parts, in which case the following information shouldprove helpful.

REMOVING AND INSTALLINGREMOVINGThese instructions are general and in some cases additionalprecautions must be taken.Drain air brake system.If water-cooled type compressor, drain engine coolingsystem, compressor cylinder head and block.Disconnect all air lines, water and oil lines to and fromcompressor.Remove compressor mounting bolts and compressor fromengine.Use a gear-puller to remove the gear or pulley fromcompressor crankshaft.INSTALLATION

ENGINE-LUBRICATED TYPESClean oil supply line. Before connecting this line to thecompressor, run the engine briefly to be sure oil is flowingfreely through the supply line.Clean the oil return line or return passages through thebrackets; these passages must be unrestricted so oil canreturn to the engine.Prelubricate compressor cylinder walls and bearings withclean engine oil before assembling compressor.Always use a new mounting gasket and be sure oil hole ingasket and compressor is properly aligned with oil supplyline.SELF-LUBRICATED TYPESFill compressor crankcase with clean engine oil beforeoperating compressor. Refer to �Tabulated Data� section forproper amount.ALL TYPESInspect pulley or gear and associated parts for wear ordamage. 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 sureit properly contacts the shaft and does not ride the key.Tighten crankshaft nut to 65-70 ft. lbs. and install cotterpin.Be sure the air cleaner is clean and properly installed. If thecompressor intake is connected to either the engine aircleaner or supercharger, these connections must be tightwith no leakage.Clean or replace any damaged or dirty air or water lineswhich may be corroded, before connecting them to thecompressor. 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, orwater leaks at compressor connections. Also check fornoisy operation.

FIGURE 15 - COMPRESSOR INTAKE ADAPTER

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REMOVING AND DISASSEMBLYREMOVINGThese instructions are general and are intended to be aguide. In some cases additional preparations andprecautions are necessary. Chock the wheels of the vehicleand drain the air pressure from all the reservoirs in the system.Drain the engine cooling system and the cylinder head ofthe compressor. Disconnect all air, water and oil lines leadingto and from the compressor. Remove the drive gear(s) orpulley from the compressor crankshaft using a gear puller.Inspect the pulley or gear and associated parts for visiblewear or damage. Since these parts are precision fitted,they must be replaced if they are worn or damaged.

DISASSEMBLYGENERALRemove road dirt and grease from the exterior of thecompressor with a cleaning solvent. Before the compressoris disassembled, the following items should be marked toshow their relationship when the compressor is assembled.Mark both the front and rear end cover in relation to thecrankcase. Mark the drive end of the crankshaft in relationto the front end cover and the crankcase. Mark the cylinderhead in relation to the block and block to crankcase. Markthe base plate or base adapter in relation to the crankcase.

A convenient method to indicate the above relationships isto use a metal scribe to mark the parts with numbers orlines. Do not use a marking method that can be wiped off orobliterated during rebuilding, such as chalk. Remove allcompressor attachments such as governors, air strainersor inlet fittings, discharge fittings and pipe plugs.

CYLINDER HEADRemove the cylinder head cap screws and tap the headwith a soft mallet to break the gasket seal. Remove theinlet valve springs form the head and inlet valves from theirguides in the block. Remove inlet valve guides from aroundthe inlet valve seats on the block, taking care not to damageseats. Scrape off any gasket material from the cylinderhead and block. Unscrew the discharge cap nuts from thehead and remove the discharge valves and springs. Inspectthe discharge valve seats for nicks, cracks, and excessivewear and remove and replace if necessary.

The discharge valve cap nuts should be inspected for wearand replaced if excessive peening has occurred. Todetermine if excessive peening has occurred, measure thedischarge valve travel. Discharge valve travel must not exceed.056 in. for the Tu Flo 400 and .046 in. for the Tu Flo 500 and1000.

FIGURE 16 - TU-FLO 400 COMPRESSOR VERTICAL MOUNT - ENGINE LUBRICATED

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CRANKCASE BASE PLATE OR ADAPTERRemove the cap screws securing the base plate or baseadapter. Tap with soft mallet to break the gasket seal. Scrapeoff any gasket material from crankcase and plate or adapter.

CONNECTING ROD ASSEMBLIES(NOTE: Before removing the connecting rods, mark each

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

Straighten the prongs of the connecting rod bolt lock strapand remove the bolts and bearing caps. Push the pistonwith the connecting rods attached out the top of the cylindersof the crankcase. Replace the bearing caps on theirrespective connecting rods. Remove the piston rings fromthe pistons. If the pistons are to be removed from theconnecting rods, remove the wrist pin lock wires or teflonplugs and press the wrist pins from the pistons andconnecting rods.

If the pistons are removed from the rod, inspect the bronzewrist pin bushing. Press out and replace the bushing if it isexcessively worn. (See Inspection of Parts.) Discard thepiston rings and the connecting rod journal bearings. Discardthe wrist pin bushings if they were removed. New Tu Flo400 compressors manufactured after approximatelySeptember 1977 will have connecting rods without bearinginserts. Repair size rods will have inserts.

REMOVING AND DISASSEMBLING BASE PLATESELF-LUBRICATED TYPE COMPRESSORS (Fig. 17)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 shouldnot be removed. If necessary, remove the bushing set screw,then bushing and shim.Remove cotter pin from oil rod cap nuts, remove nuts, oilpump piston rod and cap.

CRANKCASE (Fig. 18)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 tocrankcase; remove end cover and its gasket. Somecompressors have crankcases that have a shoulder forpositioning the crankshaft. In these cases the crankshaftmust be removed through one particular end.

Press the crankshaft and ball bearings from the crankcase,then press ball bearings from crankshaft. Many compressorswill have sleeve-type bearings in the crankcase or in the endcover. If the clearance between crankshaft journal andbearing exceeds .0065 in. the sleeve bearing should bereplaced with appropriate undersize.

BLOCK (Fig. 19)If compressor is fitted with an air strainer, inlet elbow orgovernor, 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 fromcylinder block.

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

Remove inlet valve guides; inlet valve seats can be removedbut only if they are worn or damaged and are being replaced.Unloader bore bushings should be inspected but not removedunless they are damaged.FIGURE 17

BASE PLATE SELF-LUBRICATED TYPE COMPRESSOR

FIGURE 18A - CRANKCASE - TU-FLO 1000

FIGURE 18 - CRANKCASE - TU-FLO 400 & 500

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CLEANING AND INSPECTION OF PARTS

CLEANINGAll parts should be cleaned thoroughly in a good cleaningsolvent before inspection.

CYLINDER HEAD ASSEMBLYRemove all carbon deposits from discharge cavities and allrust and scale from cooling cavities of cylinder head body.Scrape all foreign matter from body surfaces and use airpressure to blow dirt particles from all cavities.

Discharge valves can be dressed by lapping them on a pieceof fine crocus cloth on a flat surface, provided they are notexcessively worn.

CYLINDER BLOCKClean carbon and dirt from inlet and unloader passages.Use air pressure to blow carbon and dirt deposits fromunloader passages.

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

OIL PASSAGEClean thoroughly all oil passages through crankshaft,connecting rods, crankcase, end covers and base plate. Ifnecessary, inspect passages with a wire and blow foreignmatter out with air pressure.

CRANKCASE - SELF-LUBRICATED TYPEThe breather should be thoroughly washed and cleaned.

The oil pump check valve in the base should be removedand replaced. It is important when the oil pump check valveis replaced that it be installed correctly with the ball stop pinend pressed in first. When installed, the ball and its seatshould be visible from the crankcase base.

INSPECTION OF PARTSCYLINDER HEAD BODY

Inspect cylinder head body for cracks or damage.

WATER-COO LED TYPEUse air pressure to test water jackets of cylinder head andblock for leakage. Replace unit if leakage is found.

DISCHARGE VALVES AND SEATSIf discharge valves are worn and grooved where they contactthe seats, they should be replaced. If the discharge valveseats are worn excessively so that there is no longer enoughmetal left to reclaim them by lapping, the seats should bereplaced.

DISCHARGE VALVE SPRING AND CAP NUTSReplace all used discharge valve springs and cap nuts.

CRANKCASE AND END COVERSCheck for cracks or broken lugs in crankcase and end covers.Also check their oil passages to make sure they are openand clean.

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

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

CYLINDER BLOCKCheck for cracks or broken lugs on cylinder block. Alsocheck unloader bore bushings to be sure they are not worn,rusted or damaged. If these bushings are to be replacedthey can be removed by running a 1/8 in. pipe thread tapinside the bushing, then inserting a 1/8 in. pipe threaded rodand pulling the bushing straight up and out. Do not use aneasy-out for removing these bushings.

INLET VALVES AND SEATSIf inlet valves are grooved or worn where they contact theseat, they should be replaced. If the inlet valve seats areworn or damaged so they cannot be reclaimed by facing,they should be replaced.

CYLINDER BORESCylinder bores which are scored or out of round by morethan 0.002 in. or tapered more than 0.003 in. should berebored or honed oversize. Oversize pistons are available in0.010, 0.020, and 0.030 oversizes.

Cylinder bores must be smooth, straight and round.

FIGURE 19 - CYLINDER BLOCK - EXPLODED VIEW

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Clearance between cast iron pistons and cylinder boresshould be between 0.002 in. minimum and 0.004 in.maximum (Fig. 20).

PISTONSCheck pistons for scores, cracks or enlarged ring grooves;replace pistons if any of these conditions are found. Measureeach piston with a micrometer in relation to the cylinderbore 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 isloose fit, the pin, piston, or both should be replaced. Checkfit of wrist pin in connecting rod bushing by rocking the piston.This clearance should not exceed 0.0015 in. Replace wristpin bushings if excessive clearance is found. Wrist pinbushings should be reamed after being pressed intoconnecting rods. Replace used wrist pin lock wires. Tu-Flo400 compressors manufactured after September 1977 willhave Teflon plugs in each end of the wrist pins instead of thelock wire. The Teflon plugs (pc. no. 292392) may be usedinstead of the lock wires on all compressors. See Fig. 21.

PISTON RINGSCheck fit of piston rings in piston ring grooves. Check ringgap with rings installed in cylinder bores. Refer to Fig. 23for correct gap and groove clearance.

All rings must be located in their proper ring grooves asshown. The rings can be identified by the width and shouldbe installed with the bevel or the pipmark (if any) toward thetop of the piston. This applies to Cast Iron Pistons (only asshown above).

Die Cast Pistons use five (5) narrow rings.

CRANKSHAFTCheck crankshaft screw threads, keyways, tapered endsand all machined and ground surfaces for wear, scores, ordamage. Crankshaft journals which are out of round morethan 0.001 in. must be reground. Bearing inserts are availablein 0.010 in., 0.020 in., and 0.030 in. undersizes for regroundcrankshafts. Main bearing journals must be maintained sobearings are snug fit. The oil seal ring groove or grooves incrankshafts fitted with oil seal rings must not be worn. Thering groove walls must have a good finish and they must besquare. Check to be sure the oil passages are open andclean through the crankshaft.

FIGURE 21 - TU-FLO 400 NEW STYLE

FIGURE 22 - TU-FLO 400 OLD STYLE

FIGURE 23 - PISTON RING POSITIONS - GAPS ANDGROOVE CLEARANCE

TU-FLO 400 COMPRESSOR

TU-FLO 500 & 1000 COMPRESSOR

COMPRESSIONRINGS (2)

COMPRESSIONRINGS (2)

CORRECT GROOVECLEARANCE

.0015�

.0030�CORRECT GAP

CLEARANCE WITH RINGIN CYLINDER

.0035�.014�

CORRECT GROOVECLEARANCE

.0035�

.0035�CORRECT GAP

CLEARANCE WITH RINGIN CYLINDER

.0035�.014�

.002�

.004�

WIDENARROW

WIDENARROW

FIGURE 20 - MEASURING CYLINDER BORES

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CONNECTING ROD BEARINGSCheck connecting rod bearings on crankshaft journals forproper fit. Used bearing inserts should be replaced.Connecting rod caps are not interchangeable. The lockingslots of the connecting rod and cap should be positionedadjacent to each other.

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

MAIN BEARINGSCheck for wear or flat spots; if found, bearings should bereplaced. If type with sleeve bearing, this bearing should bechecked for scores and wear and replaced if necessary.

UNLOADER MECHANISMUsed unloader mechanism should be replaced by unloaderkits 265014 for Type Tu-Flo 400 compressors and 265015for Types Tu-Flo 500 and 1000 compressors. The Tu-Flo1000 compressor requires two kits per compressor.

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

PARTS SPECIAL TO SELF-LUBRICATEDTYPE COMPRESSORSOIL PUMP SCREENCheck oil pump screen to be sure it is clean and notdamaged; replace if damaged.

OIL PUMP PISTON AND BUSHINGCheck fit of oil pump piston in base plate pump bushing. Itmust be a medium sliding fit. If excessive clearance isfound, the oil rod and/or bushing must be replaced.

OIL PUMP RELIEF VALVEIf the oil pump relief valve is defective, it should be replaced.

OIL PUMP CHECK VALVEThe check valve should be replaced. It can be checked byapplying air pressure back through the pin stop end andnoting that the balI check seals on its seat.

REPAIRSDISCHARGE VALVES AND SEATSIf discharge valve seats merely show signs of slight wear,they can be dressed by using a lapping stone, grindingcompound and grinding tool. Install new discharge valvesand valve springs.

To test for leakage by the discharge valves, apply about 100pounds of air pressure through the cylinder head dischargeport and apply soap suds at the discharge valves and seats.

Leakage which will permit the formation of bubbles ispermissible.

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. Thiswill help the valves to seat and should reduce any leakage.

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

INLET VALVES AND SEATSIf inlet valve seats show sign of slight nicks or scratches,they can be redressed with a fine piece of emery cloth or bylapping with a lapping stone, grinding compound and grindingtool. If the seats are excessively damaged to the extentthat they cannot be reclaimed, they should be replaced.The dimension from the top of the cylinder block to the inletvalve seat should not exceed 0.118 in. nor be less than0.101 in.

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

ASSEMBLYINSTALLING CYLINDER BLOCKPosition cylinder block gasket and block on crankcaseaccording to markings made prior to disassembly. Usingcap screws with lock washers, secure cylinder block tocrankcase.

INSTALLING CRANKSHAFTIf the crankshaft is fitted with oil seal rings, install rings.Position ball bearings and crankshaft in crankcase, makingsure the drive end of the crankshaft is positioned as markedbefore disassembly.

If one end of the crankcase is counterbored for holding abearing, be sure the crankshaft is installed through the correctend of the crankcase.

Carefully press crankshaft and bearings into crankcase usingarbor press.

Position a new rear end cover gasket, when used, over therear end of the crankcase, making sure the oil hole in thegasket lines up with the oil hole in the crankcase. Positionend cover with oil seal ring, if used, installed over crankcaseand end cover gasket. The end cover should be positionedcorrectly in relation to the oil holes in the gasket andcrankcase. Secure end cover to crankcase with cap screwsand lock washers.

If the opposite end cover requires an oil seal which wasremoved on disassembly, a new seal should be pressedinto end cover. Position new end cover gasket and carefully

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install end cover over crankshaft and to crankcase, avoidingdamage to the seal. Secure end cover with cap screw andlock washers.

PISTONS AND CONNECTING RODSIf new wrist pin bushings are to be used, they should bepressed into the connecting rods so that the oil hole in thebushing lines up with the one in the rod. The new bushingsshould then be reamed or honed to provide between 0.0002in and 0.0007 in. clearance on the wrist pin. Positionconnecting rod in piston and press in wrist pin so thatlockwire hole in the pin aligns with that of the piston. Installnew lockwire through piston and wrist pin and lock same bysnapping short end into lockwire hole at the bottom of thepiston (Fig. 7). Teflon plugs in wrist pin ends may be usedinstead of the lockwires (Fig. 21).

Install piston rings in correct location with ring pipmarks up(Fig. 23). Stagger the position of the ring gaps.

Prelubricate piston, piston rings, wrist pin and connectingrod bearings with clean engine oil before installing them inthe compressor.

Remove connecting bolts and bearing cap from oneconnecting rod. Turn crankshaft so one of its connectingrod journals is in the downward, center position. Compressthe rings with a ring compression tool and insert theconnecting rod with piston through the top of the cylinderwhose journal is down. Position and attach the bearing capto the connecting rod, making sure the bolt lock washersare properly positioned on the cap. Tighten connecting rodbolts evenly and bend the two new lock washer prongs upagainst the hex head of the bolt. Install the other connectingrod and piston in the same manner.

UNLOADER MECHANISM (Fig. 24)The unloader pistons and their bores must be lubricatedwith special lubricant piece number 239379 (dimethylpolysiloxane) prior to installation. If new unloader kits arebeing installed, the pistons in the kit are already lubricated.

Install the unloader pistons in their bores with caution againstcutting the grommets or distorting the back-up rings. Positionunloader plungers in their guides and slip them in and overthe tops of the pistons.

Install the unloader spring seat in the cylinder block; a smallhole is drilled in the block for this purpose. Position thesaddle between unloader piston guides so its forks arecentered on the guides. Install the unloader spring, makingsure it seats over the spring seats both in the block and onthe saddle.

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

CYLINDER HEAD ASSEMBLYIf previously removed, the discharge valve seats should beinstalled. Drop discharge valves into their seats. Installdischarge valve springs and cap nuts.

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

BASEPLATESELF-LUBRICATED TYPE COMPRESSORSInstall oil pump piston and rod on crankshaft.

Oil rod bearing fit must be the same as specified forconnecting rod bearings. Install oil rod cap nuts and cotterpins to lock oil rod nuts.

Install oil pump relief valve in base plate. The relief valve canbe tested at this stage by applying air pressure to the reliefvalve. The valve should open when the pressure is between14 psi minimum and 24 psi maximum. When the relief valveis properly installed in the base plate, install set screw thatlocks 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. Installblanking cover on opposite oil filter fitting hole in plate.

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

FIGURE 24 - UNLOADER MECHANISM

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AIR STRAINERIf the compressor is type with air strainer, assemble strainer(Fig. 25). Using a new strainer gasket, install strainer oncylinder block.

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

INSPECTION OF REBUILT UNITCheck to be sure that covers, plugs or masking tape areused to protect all ports if compressor is not to be installedimmediately.

Fit the end of all crankshafts with keys, nuts and cotter pinsas required and then protect the ends against damage bywrapping with masking or friction tape.

The open bottom of engine lubricated compressors shouldbe protected against the entrance of dirt during handling orstorage, by installing a temporary cover over base.

TESTING REBUILT COMPRESSORIn order to properly test a compressor under operatingconditions, a test rack for correct mounting, cooling,lubricating and driving the compressor is necessary. Suchtests are not compulsory if the unit has been carefully rebuiltby an experienced person.

A compressor efficiency or build-up test can be run which isnot too difficult. Before the test, the crankcase of a self-lubricated type compressor should be properly filled withlubricating oil. An engine lubricated compressor must beconnected to an oil supply line of at least 15 pounds pressureduring the test and an oil return line must be installed tokeep the crankcase drained. The compressor (when tested)should be tested without a strainer.

To the discharge port of the compressor, connect a reservoiror reservoirs whose volume plus the volume of the connectingline equals 1,300 cubic inches. Run the compressor between1,700 and 1,750 RPM. Elapsed time that the compressortakes to build up from 0 to 100 psi depends on the typecompressor as follows:

BUILD-UP TIMETYPE COMPRESSOR 0 TO 100 PSI

TU-FLO 400 47 SECONDS MAXIMUMTU-FLO 500 30 SECONDS MAXIMUM

TU-FLO 1000 15 SECONDS MAXIMUMDuring the above test the compressor should be checkedfor oil leakage and noisy operation.

IMPORTANT! PLEASE READWhen working on or around a vehicle, the followinggeneral precautions should be observed:1. Park the vehicle on a level surface, apply the parking

brakes, and always block the wheels.2. Stop the engine when working around the vehicle.3. If the vehicle is equipped with air brakes, make certain

to drain the air pressure from all reservoirs beforebeginning ANY work on the vehicle.

4. Following the vehicle manufacturer�s recommendedprocedures, deactivate the electrical system in a mannerthat removes all electrical power from the vehicle.

5. When working in the engine compartment the engineshould be shut off. Where circumstances require thatthe engine be in operation, EXTREME CAUTION shouldbe used to prevent personal injury resulting from contactwith moving, rotating, leaking, heated, or electricallycharged components.

6. Never connect or disconnect a hose or line containingpressure; it may whip. Never remove a component orplug unless you are certain all system pressure hasbeen depleted.

7. Never exceed recommended pressures and always wearsafety glasses.

8. Do not attempt to install, remove, disassemble orassemble a component until you have read andthoroughly understand the recommended procedures.Use only the proper tools and observe all precautionspertaining to use of those tools.

9. Use only genuine Bendix replacement parts, componentsand kits. Replacement hardware, tubing, hose, fittings,etc. should be of equivalent size, type, and strength asoriginal equipment, and be designed specifically for suchapplications and systems.

10. Components with stripped threads or damaged partsshould be replaced rather than repaired. Repairs requiringmachining or welding should not be attempted unlessspecifically approved and stated by the vehicle orcomponent manufacturer.

11. Prior to returning the vehicle to service, makecertain all components and systems are restoredto their proper operating condition.

FIGURE 25 - AIR STRAINER - EXPLODED VIEW

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MAINTENANCE INSTRUCTIONS FORLARGE SUMP TU-FLO 1000 COMPRESSOR288578 (SPECIAL APPLICATION)This compressor is an air-cooled, belt driven, self lubricated,V-four cylinder compressor. It is driven by an electric motorand cooling air is supplied by a fan on the driven pulley. Thesystem air pressure is controlled between 135 psi and 150psi by a pressure switch starting and stopping the electricmotor.

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

SCHEDULED MAINTENANCENOTE: When checking or adding oil or servicing the

crankcase breather, care should be taken to preventdirt or foreign material from entering the breather or oilsump.

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 ports and replace withfreshly oiled curled hair.

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

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TABULATED DATA

Tu-Flo Tu-Flo Tu-Flo400 500 1000

Number Cylinders 2 2 4Bore Size 2.0625" 2.5" 2.5"Stroke1. 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

2,400 air cooled 2,400 air cooled 2,400 air cooledMinimum coolant flow at 2.5 gal./min. 2.5 gal./min. 2.5 gal./ min.

maximum RPM water cooled water cooled water cooled250 CFM air flow 250 CFM air flow 250 CFM air flow

Approximate horsepower requiredat 1,250 RPM 1.2 H.P. 2.3 H. P. 4.6 H. P.

Maximum inlet air temperature 2,500 F. 2500 F. 2,500 F.Maximum discharge air temperature 4,000 F. 4000 F. 4,000 F.Minimum pressure required

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

engine idling speed 5 PSI 5 PSI 5 PSIMinimum oil pressure required at

maximum governed engine speed 15 PSI 15 PSI 15 PSIApproximate 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

or equivalent or equivalent from each head to a commonmanifold with 1" tubing from

manifold.Minimum coolant line size 3/8" O.D. tubing 1/2" O.D. tubing 1/2" O.D. tubing

or equivalent or equivalent or equivalentMinimum oil supply line size 1/4" O.D. tubing 1/4" O.D. tubing 1/4" O.D. tubing

or equivalent or equivalent or equivalentMinimum oil return line size 1/2" O.D. tubing 5/8" O.D. tubing 5/8" O.D. tubing

or equivalent or equivalent or equivalent**Minimum air inlet line size 5/8" I.D. 5/8" I.D. 1" I.D. if equipped with inlet

manifold; or, dual 5/8" I.D. linesfrom engine to compressor inlets.

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

COMPRESSOR TROUBLESHOOTING CHARTSYMPTOMS CAUSE REMEDY

1. Compressor passes excessive A. Restricted air intake. A. Check engine or compressor air cleaner andoil as evidenced by presence replace if necessary. Check compressor airof oil at exhaust ports of inlet line for kinks, excessive bends and bevalving or seeping from air certain inlet lines have the minimumstrainer. specified inside diameter. Recommended

minimum inlet line inside diameter is 5/8".Recommended maximum air inlet restrictionis 25" of water.

B. Restricted oil return B. Oil return to the engine should not be in(to engine). any way restricted. Check for excessive

bends, kinks, and restrictions in the oilreturn line. Minimum recommended oilreturn line size is 5/8" O.D. tubing orequivalent I.D. (1/2" minimum). Returnline must CONSTANTLY DESCEND fromthe compressor to the engine crankcase.Make certain oil drain passages in thecompressor and mating engine surfacesare unobstructed and aligned. Specialcare must be taken when sealants areused with, or instead of, gaskets.

15


SYMPTOMS CAUSE REMEDY

C. Poorly filtered inlet air. C. Check for damaged, defective or dirty airfilter on engine or compressor. Check forleaking, damaged or defective compressorair intake components (i.e., induction line,fittings, gaskets, filter bodies, etc). Thecompressor intake should not beconnected to any part of the exhaust gasrecirculation (E.G.R.) system on theengine.

D. Insufficient compressor D. For air-cooled compressor or air-cooledcooling (compressor runs portions of the compressor:hot). 1. Remove accumulated grease, grime, or

dirt from the cooling fins. Replacecomponents found damaged.

2. Check for damaged cooling fins.Replace components found damaged.

3. Air-cooled compressors should not beused on engines equipped with fanclutches.

For water-cooled compressor or water-cooled portions of the compressor:1 . Check for proper coolant line sizes.

Minimum recommended size is 1/2"O.D. tubing.

2. Check the coolant flow through thecompressor. Minimum allowable flowis 2.5 gallons per minute at enginegoverned speed. If low coolant flow isdetected, inspect the coolant lines andfittings for accumulated rust scale, kinksand restrictions.

3. Water temperature should not exceed200 0 F.

4. Optimum cooling is achieved whenengine coolant flows into the com

` pressor cylinder block at one end andout the compressor cylinder head at theopposite end.

E. Contaminants not being E. Check reservoir drain valves to ensureregularly drained from that they are functioning properly. It issystem reservoirs. recommended that the vehicle be

equipped with functioning automaticdrain valves, or have all reservoirsdrained to zero (0) psi daily, or

optimally to be equipped with adesiccant-type air dryer prior to thereservoir system.

F. Compressor runs loaded an F. Vehicle system leakage should notexcessive amount of time. exceed industry standards of onepsi

pressure drop per minute withoutbrakes applied, and three psipressure drop per minute with brakesapplied. If leakage is excessive,check for system leaks and repair.

G. Excessive engine crankcase G. Test for excessive engine crankcasepressure. pressure and replace or repair

crankcase ventilation components asnecessary. (An indication ofcrankcase pressure is a loose orpartially lifted dipstick.)

H. Excessive engine oil H. Check the engine oil pressure with apressure. test gauge and compare the reading to

the engine specifications. Bendixdoes not recommend restricting thecompressor oil supply line because ofthe possibility of plugging therestriction with oil contaminants.Minimum oil supply line size is 1/4"O.D. tubing.

I. Faulty compressor. I. Replace or repair the compressor onlyafter making certain none of thepreceding installation defects exist.

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SYMPTOMS CAUSE REMEDY

2. Noisy compressor operations. A. Loose drive gear or pulley. A. Inspect the fit of the drive gear on pulley onthe compressor crankshaft. The pulley ongear must be completely seated and thecrankshaft nut must be tight. If thecompressor crankshaft surface or itskeyway are damaged, it is an indication ofloose drive components. If damage to thecompressor crankshaft is detected,replace the compressor or the crankshaft.When installing the drive gear or pulley,torque the crankshaft nut to 100 footpounds. DO NOT BACK OFF THECRANKSHAFT NUT TOALIGN THE COTTER PIN ANDCASTELLATED NUT. (Some compressorsdo not use castellated nuts.) DO NOT USEIMPACT WRENCHES.

B. Excessively worn drive B. Inspect drive gear and couplings and enginecouplings or gears. for excessive wear. Replace as necessary.

(Non-metallic gears should be replacedwhen the compressor is changed.) 501drive gear should be metal-type onDetroit Diesel engine.

C. Compressor cylinder head or C. Inspect the compressor discharge port anddischarge line restrictions. discharge line for carbon build-up. If

carbon is detected, check for propercooling to the compressor. (See Causeand Remedy (D) under Symptom #1.)Inspect the discharge line for kinks andrestrictions. Replace discharge line asnecessary.

D. Worn or burned out D. Check for proper oil pressure in thebearings. compressor. Minimum required oil

pressure, 5 psi engine idling, 15 psimaximum governed engine rpm. Check forexcessive oil temperature - should notexceed 240° F.

E. Faulty compressor. E. Replace or repair the compressor afterdetermining none of the preceding installationdefects exist.

3. Excessive build-up and A. Dirty induction air filter. A. Inspect engine or compressor air filter andrecovery time. Compressor replace if necessary.should be capable of buildingair system from 85-100 psi in B. Restricted induction line. B. Inspect the compressor air induction line40 seconds with engine at for kinks and restrictions andfull governed rpm. Minimum replace as necessary.compressor performance is C. Restricted discharge line or C. Inspect the compressor discharge port andcertified to meet Federal compressor discharge cavity. line for restrictions and carbon build-up.requirements by the vehicle If a carbon build-up is found, check formanufacturer. Do not proper compressor cooling.downsize the original Replace faulty sections of the dischargeequipment compressor. line.

D. Slipping drive components. D. Check for faulty drive gears and couplingsand replace as necessary. Check thecondition of drive belts and replace or tighten,whichever is appropriate.

E. Excessive air system leakage. E. Test for excessive system leakage and repairas necessary. Use the following as aguide: Build system pressure to governorcutout and allow the pressure to stabilizefor one minute. Using the dash guage,note the system pressure and thepressure drop after two minutes.The pressure drop for Pre-1975 vehiclesshould not exceed:1. 4 psi for a single vehicle.2. 6 psi for a tractor trailer.3. 10 psi for a tractor and 2 trailers.The pressure drop for Post-1975 vehiclesshould not exceed:1. 2 psi in each reservoir for a single

vehicle.2. 6 psi in each reservoir for a tractor and

17


trailer.SYMPTOMS CAUSE REMEDY

3. 8 psi in each reservoir for a tractor andtwo trailers.

F. Sticking unloader pistons F. Check the operation of the unloadingand plungers. pistons in the inlet cavity of the

compressor. Both pistons should have theplunger flanges resting on the inlet cavityfloor when the compressor is loaded(pumping air). If the pistons and plungerare not fully retracted, check for properoperation of the compressor air governor.If the governor is operating properly,replace the unloader pistons and plungersand inspect their bores in the cylinderblock. Clean and lubricate as necessary.Inspect for bent, kinked or blocked tubingleading to or from the governor.

G. Faulty compressor. G. Replace or repair the compressor afterdetermining none of the precedinginstallation defects exist.

4. Compressor fails to unload. A. Faulty governor or governor A. Test the governor for proper operationinstallation. and inspect air lines to and from the

governor for kinks or restrictions. Replaceor repair the governor or its connecting airlines.

B. Faulty or worn unloader B. Inspect for worn, dirty or corroded unloaderpistons or bores. pistons and their cylinder block bores.

Replace as necessary.

5. Compressor leaks oil. A. Damaged mounting gasket. A. Check the compressor mounting bolttorque. If the mounting bolt torque is low,replace the compressor mounting gasketbefore retorquing the mounting bolts.

B. Cracked crankcase, cylinder B. Visually inspect the compressor exteriorblock or end cover. for cracked or broken components.

Cracked or broken crankcases ormounting flanges can be caused by loosemounting bolts. The end cover can becracked by over torquing fitting or plugsinstalled in the end cover. Replace orrepair the compressor as necessary.

C. Loose end cover or cylinder C. Check the cap screw torques and tightenblock cap screws. as necessary.

D. Loose oil supply or return D. Check the torque of external oil lineline fittings. fittings and tighten as necessary.

E. Porous compressor casting. E. Replace the compressor if porosity isfound.

F. Mounting flange or end F. Replace as necessary.cover, O-Ring or gasketmissing, cut or damaged.

6. Compressor constantly cycles A. Leaking compressor A. Remove the compressor inlet air strainer(compressor remains unloader pistons. or fitting. With the compressor unloadedunloaded for a very short (not compressing air), check for airtime). leakage around the unloader pistons.

Replace as necessary.B. Faulty governor. B. Test the governor for proper operation and

repair or replace as necessary.C. Excessive system leakage. C. Test for excessive system leakage as

instructed in Symptom 3, Remedy E.Reduce leakage wherever possible.

D. Excessive reservoir D. Drain reservoirs.contaminants.

7. Compressor leaks coolant. A. Improperly installed plugs A. Check torque of fittings and plugs andand coolant line fittings. tighten as necessary. Over-torqued fittings

and plugs can crack the head or blockcasting.

B. Freeze cracks due to B. Test anti-freeze and strengthen asimproper anti-freeze necessary. Check coolant flow throughstrength. compressor to assure the proper

anti-freeze mixture reaches thecompressor.

C. Faulty compressor (porous C. If casting porosity is detected, replacecastings). the compressor.

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BW1420 © Honeywell Commercial Vehicle Systems Company . 1/1999 Printed in U.S.A.

8. Compressor head gasket A. Restricted discharge line. A. Clear restriction or replace line.failure.

B. Loose head bolts. B. Tighten evenly to a torque of 25-30 footpounds.

C. Faulty compressor or head C. Check for rough or poorly machinedgasket. head or block surfaces. Replace

necessary components.

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Tf 500 Compressor Service

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