Air Compressor Bendix Tu-flo 501 (1)

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SERVICE MANUAL SECTION

AIR

AIR COMPRESSOR:

COMPRESSOR: B

BENDIX

ENDIX TU-FLO

TU-FLO 501

501 V

Vendor:

endor: BEN

BENDI

DIX

X

Model:

Model: 20

2000

00 Model:

Model: 30

3000

00 Model:

Model: 40

4000

00 Model:

Model: 70

7000

00 Model:

Model: 81

8100

00 Model:

Model: 82

8200

00 Model:

Model: 83

8300

00 V

Vendor Code:

endor Code: 04

04SBA

SBA

s04010, Formerly CTS-5145

03/31/1996

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7. C. CLELEAN AN ANAND D IINNSSPPEECCTT... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...1111 7.1. CYLINDER HEAD... ... 7.1. CYLINDER HEAD... ...1111 7.2. CRANKCASE... ... 7.2. CRANKCASE... ...1111 7.3. PISTONS... ... 7.3. PISTONS... ...1212 7.4. CRANKSHAFT... ... 7.4. CRANKSHAFT... ...1313 7.5. END COVER... ... 7.5. END COVER... ...1313 7.6. CONNECTING ROD BEARINGS... 7.6. CONNECTING ROD BEARINGS...1313 8. REPAIR... ... 8. REPAIR... ...1414

8.1. DISCHARGE VALVES, VALVE STOPS AND SEATS (FIGUR

8.1. DISCHARGE VALVES, VALVE STOPS AND SEATS (FIGUR E 13 )...E 13 )...1414 8

8.2.2. . DDIISCSCHHARARGE GE VVALALVVEES LES LEAKAAKAGE GE TTESESTT... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...1414 8.3. INLET VALVES AND SEATS... 8.3. INLET VALVES AND SEATS...1414 9. REASSEMBLE... ... 9. REASSEMBLE... ...1515 10. TESTING... ... 10. TESTING... ...18.18 1

111. TR. TROOUUBLBLEESSHHOOOOTTIINNGG... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...1919 1

122. . SSPPEECCIIFFIICCAATTIIOONNSS... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ....2323 1 122..11. . CCOOMMPPRREESSSSOOR R DDAATTA...A... ... ... ... ... ... ... ... ... ... ... ... ..2323 1 122..22. . MMEEASASUURREEMMEENNTTSS... ... ... ... ... ... ... ... ... ... ... ... ... ... ...2525 1 122..33. T. TOORRQQUUE CE CHHARARTT... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ..2626

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DESCRIPTION

The Tu-Flo 501 air compressor (Figure 1 ) is a two-cylinder, single stage, reciprocating piston type, with a rated displacement of 12 cubic feet of air per minute at 1250 RPM.

Figure 1 Tu-Flo 501 Air Compresso r

The compressor is constructed of two major assemblies: the head and the crankcase. The head houses the discharge valving and is installed on the upper portion of the crankcase. The crankcase is a one-piece casting combining the cylinder block and crankcase. The upper portion of the casting houses the cylinder bores and inlet valving and the lower portion houses the crankshaft and main bearings.

Two methods are employed for cooling the compressor during operation. The cylinder head is connected to the engine’s cooling system, while the cylinder bore portion of the crankcase has external ﬁns for ef ﬁcient cooling. All Tu-Flo 501 compressors utilize the engine’s oil pressure system to lubricate internal moving parts.

1. OPERATION

The compressor is driven by the engine and runs continuously while the engine is operating, but the actual compression of air is controlled by the governor which, acting in conjunction with the unloading mechanism in the compressor, starts or stops the compression of air by loading or unloading the compressor when the pressure in the air brake system reaches the minimum or maximum air pressure levels.

1.1. INTAKE A ND COMPRESSION OF AIR (LOADED)

During the downstroke of each piston, a slight vacuum is created between the top of the piston and the head, causing the ﬂat circular inlet valve to move up and off its seat. The ﬂat discharge valve will remain on its seat. Air drawn through the intake port on the down stroke enters the cylinder above the piston through the inlet valve (Figure 2 ). As the piston starts the upward stroke, the air is being compressed. Air pressure on top of the inlet valve plus the force of its spring returns the inlet valve to its seat. The piston continues

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the upward stroke and compressed air then ﬂows by the open discharge valve into the discharge line and on to the reservoirs (Figure 3 ).

Figure 2 Intake and Compression of Air

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1.2. NOT COMPRESSING AIR (UNLOADED)

When the air pressure in the reservoir reaches the maximum setting of the governor, the governor allows air to pass from the reservoir into the cavity beneath the unloader pistons. This lifts the unloader piston and plungers. The plungers move up and hold the inlet valves off their seats (Figure 4 ).

Figure 4 Not Compressing Air (Unloaded)

With the inlet valves held off their seats by the unloader pistons and plungers, air is pumped back and forth between the two cylinders. When air is used from the reservoir and the pressure drops to the cut-in setting of the governor, the governor closes and 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.

2. LUBRICATION

The Bendix Tu-Flo 501 air compressor is lubricated by the engine oil, therefore it is recommended that the engine oil be checked regularly and changed at proper intervals.

3. COOLING

The Bendix Tu-Flo 501 air compressor cylinder head is cooled by the engine cooling system, therefore it is recommended that the cooling system be checked regularly.

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4. MAINTENANCE

4.1. AIR STRAINER (FILTER)

Refer to the Operator’s Manual for the interval that the air strainers (ﬁlters) should be cleaned or replaced. The operating conditions, experience and type of strainer used may designate more frequent service of the air strainers.

4.2. POLYURETHANE SPONGE STRAINER (FIGURE 5 )

Figure 5 Polyurethane Sponge Strainer

Remove and wash all parts. The straine r 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 squeeze d dry before replacing it in the strainer. Be sure to replace the gasket if entire strainer was removed from compressor intake.

4.3. DRY ELEMENT — PLEATED PAPER AIR STRAINER (FIGURE 6 )

Figure 6 Dry Paper Strainer

Remove spring clips from side of mounting baf fle and remove cover. Replace pleated paper filter and reinstall cleaner cover making sure the filter is in position. Be sure to replace air strainer gasket if entire strainer is removed from compressor intake.

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4.4. COMPRESSORS WITH INTAKE ADAPTERS (FIGURE 7 )

Figure 7 Adapter to Engine Air Cleaner

The compressor receives clean air from engine air cleaner. When the engine air cleaner is serviced or the

ﬁlter is changed, the intake adapter and hose should be inspected. Inspect connecting hoses for ruptures or loose connections. Replace hose if required or tighten connections if needed. If intake adapter is loose, remove it, clean strainer plate (if applicable) and replace adapter gasket. Then reinstall adapter; tighten all hose connections securely.

4.5. EVERY 50,000 MILES (80,000 KM) OR 6 MONTHS

Remove discharge head ﬁttings and inspect the compressor discharge port and discharge line for excessive carbon deposits. If excessive carbon is noted, the discharge line must be cleaned or replaced and compressor checked more thoroughly, paying special attention to air induction system, oil supply and return system, and proper cooling. If necessary, repair or replace compressor. Check for proper belt pulley alignment and belt tension. Adjust, if required, paying special attention not to overtighten belt tension. Check for noisy compressor operation which could indicate a worn drive gear coupling or a loose pulley. Adjust and/or replace as required. Check all compressor mounting bolts; retighten evenly, if necessary. Check for leakage and proper unloader mechanism operation. Replace any defective parts.

4.6. EVERY 200,000 MILES (322,000 KM) OR 24 MONTHS

Perform a thorough inspection by disassembling the compressor. Clean and inspect all parts thoroughly; repair or replace all worn or damaged parts or replace compressor depending upon the results of inspection and experience.

CAUTION – In the event it becomes necessary to drain the engine cooli ng system to prevent damage from freezing, be sure the cylinder head of t he compressor is drained also.

4.7. OPERATION TESTS

Vehicles manufactured after the effective date of FMVSS 121, with the minimum required reservoir volume, must have a compressor capable of raising air system pressure from 85 to 100 psi in 25 seconds or less, with the engine operating at maximum governed speed. The vehicle must be certi ﬁed of this performance on new vehicles with all allowances for air systems with greater than minimum required reservoir volume.

4.8. AIR LEAKAGE TESTS

Air leakage past the discharge valves can be detected by removing the discharge line, applying air back through the discharge port and listening for air escaping. The discharge valves and the unloader piston

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can be checked for leakage by building up the air system until the governor cuts out, then stopping the engine. With the engine stopped, listen for air escaping at the air compressor intake. To pinpoint leakage if noted, apply a small amount of oil around the unloader pistons. If there is no leakage noted at the unloader pistons, the discharge valves may be leaking. If it is not functioning as described or leakage is excessive, it is recommended that it be repaired or replaced.

5. REMOVE

WARNING – When any component is serviced or removed from the air system, be sure to set the parking brake and block the vehicle wheels to prevent it from moving while service is being performed.

1. Drain air pressure from all reservoirs.

2. Drain engine cooling system and cylinder head of compressor.

3. Disconnect all air, water and oil lines leading to and from the compressor. 4. Remove compressor mounting bolts and drive belts as required.

5. Remove compressor from engine.

6. Use suitable puller to remove pulley or gear from compressor crankshaft after removing crankshaft nut. 7. Inspect pulley or gear and related parts for wear or damage. If any parts are found worn or damaged,

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6. DISASSEMBLE

Before disassembling the compressor, the following parts should be marked for correct alignment at reassembly. Scribe mark front and rear end covers in relation to cra nkcase. Mark drive end of crankshaft. Mark cylinder head in relation to crankcase and mark base plate or base adapter (Figure 8 and Figure 9 ).

Figure 8 Alignment Marks

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1. CRANKSHAFT NUT

2. ADAPTER COVER FLANGE WITH BEARING 3. END COVER O-RING

4. CRANKSHAFT BEARING 5. CONNECTING ROD BOLT 6. CONNECTING ROD BEARING 7. CONNECTING ROD WITH CAP 8. PISTON WITH PIN

9. PISTON RING SET

10. LOCK WRIST PIN WIRE 11. PISTON WRIST PIN 12. CYLINDER HEAD

13. DISCHARGE VALVE SPRING 14. DISCHARGE VALVE

15. DISCHARGE VALVE SEAT 16. CYLINDER HEAD GASKET 17. INLET VALVE BUSHING 18. INLET VALVE SEAT 19. INLET VALVE SPRING 20. INLET VALVE

21. INLET VALVE STOP 22. INLET VALVE GUIDE 23. BACK-UP RING 24. O-RING

25. REAR COVER WITH BEARING 26. THRUST WASHER

27. AIR COMPRESSOR CRANKSHAFT 28. AIR COMPRESSOR CRANKCASE 29. CRANKCASE GASKET

30. CRANKCASE COVER

31. CRANKCASE COVER O-RING 32. CRANKSHAFT BUSHING 33. CRANKSHAFT KEY

1. Remove all attachments such as governor, air strainer inlet ﬁttings, discharge ﬁttings and pipe plugs. 2. Remove six cylinder head capscrews and tap the head with a soft mallet to break the gasket seal. Remove

head and gasket.

3. Remove inlet valve springs from the head, and inlet valves from their guides in the crankcase. Remove inlet valve guides from the valve seats on crankcase taking care not to damage seats.

4. Scrape off gasket material from cylinder head and crankcase.

5. Unscrew discharge valve seats from cylinder head and remove discharge valve and springs.

6. To remove the discharge valve stops, support the machined surface of the cylinder head on an arbor press bed and carefully press the stops from the top of the head and out the bottom. Be sure to allow suf ﬁcient clearance for the stops between the press bed and bottom of cylinder head. Discard inlet valve and springs. If the discharge valves, springs, and valve seats are defective, replace them.

7. Remove base plate or adapter mounting capscrews. Use a soft hammer or mallet to break seal. Clean seal material from surfaces.

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8. Before removing the connecting rods, mark each rod and its cap. Connecting rods are matched to their own cap for proper bearing ﬁt and parts should not be interchanged. Straighten the lock tabs on connecting rod locks and remove bolts and bearing caps. Push the piston with connecting rod out top of cylinders of the crankcase (Figure 10 ).

Figure 10 Connecting Rod Out Top of Cylinders

9. Reassemble bearing caps on their respective connecting rods. 10. Remove piston rings from piston.

11. Remove pistons from connecting rods by removing wrist pin lock wires or teﬂon plugs and press the wrist pins from pistons and connecting rods. If wrist pin bushing is excessively worn, press out worn bushing and press in new bushing.

12. Remove key from crankshaft. Through drive type compressors may have a crankshaft key at each end. Remove drive end cover. Remove end cover.

13. Remove both small seal rings from crankcase and O-ring from the front end cover.

14. Remove capscrews from rear end cover and remove rear end cover. Use care in removing end cover so as not to damage main bearing if bearing is used.

15. Remove both small seal rings from crankcase and O-ring from end cover.

16. If compressor is equipped with ball type main bearings, press crankshaft and ball bearings from crankcase. Then press bearings from crankshaft.

17. Remove unloader spring, spring saddle and spring seat from the inlet cavity of crankcase using a long nose pliers.

18. Remove unloader plunger and guides.

19. Position a shop cloth over the inlet cavity and apply air pressure to governor mounting pad unloader port to blow the unloader pistons out of their bores and into the inlet cavity.

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7. CLEAN AND INSPECT

Clean all parts using cleaning solvent to remove all dirt, oil and grease. Use compressed air to dry parts.

7.1. CYLINDER HEAD

Scrape off all cylinder head gasket material from mounting surface. Remove all carbon deposits from discharge cavities and any rust and scale from cooling cavities of cylinder he ad. Scrape all foreign matter from the body surfaces and use compressed air to blow dirt from all cavities. Ins pect cylinder head for cracks or damage. Inspect discharge valve seats for nicks, cracks and excess ive wear and replace if necessary. Discharge valve stop should be inspected for wear and replaced if excessive peening has occurred. To determine if excessive peening has occurred, measure discharge valve travel. Valve travel should not exceed .057 inch (1.448mm). To remove discharge valve stops, refer to Step No. 6 in DISASSEMBLE.

Valve stop bores in the cylinder head must be inspected f or excessive scoring. Replace with new cylinder head body if excessive scoring is present.

7.2. CRANKCASE

Scrape all gasket material from crankcase mounting surface and cylinder head mounting. Clean all carbon and dirt from inlet and unloader passages. Use compr essed air to blow excessive dirt and carbon deposits from unloader passages. Clean all oil passages i n crankcase.

Inspect crankcase surfaces for cracks and d amage.

On compressors with ball bearing main beari ngs, the difference between the O.D. of the outer race and the I.D. of the crankcase bore should be .0000 - .0015 inch (.000 - .0381mm) loose to maintain the correct press ﬁt. Replace crankcase if the ﬁt is too loose.

On compressors with sleeve-type main bearings, the difference between the O.D. of the crankshaft journal and main bearing I.D. must not exceed .006 5 inch (.1651mm). If clearance is greater than .0065 inch (.1651mm), the end cover or main bearing must be replaced.

Check the unloader bore bushings to be sure they are not worn, rusted or damaged. If bushings are to be replaced, they can be removed by r unning a 1/8‟ pipe thread tap into the bushing and inserting a 1/8‟ pipe

threaded rod and pulling the bus hing straight up and out. Do not use an easy-out for removing these bushings. If inlet valve seats are worn or damaged, so they cannot be reclaimed by facing, they should be replaced. Cylinder bores should be checked with an inside micrometer or calipers (Figure 11 ).

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Figure 11 Measuring Cylinder Bores

Cylinder bores which are scored or out-of- round by more than .001 inch (.0254mm) or tapered more than .002 inch (.0508mm) should be rebored or honed oversize. Over-sized pistons and piston rings are available in .010 inch (.2540mm), .020 inch (.5080 mm) and .030 inch (.7620mm) oversizes. Cylinder bores must be smooth, straight and round. Clearance between cast iron pistons and cylinder bores should be between .002 inch (.0508mm) minimum and .004 inch (.1016mm) maximum (Figure 12 ).

Figure 12

7.3. PISTONS

Check pistons for scores, cracks or enlarged ring grooves. Measure piston with a micrometer in relation to cylinder bore diameter.

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Clearance between the cast iron pistons and cylinder bores should be between .002 inch (.0508mm) minimum and .004 inch (.1016mm) maximum (Figure 12 ).

Check the fit of the wrist pin to the pistons and connecting rod bushings. Wrist pin should be a light press fit in the piston. If wrist pin is a loose fit, the piston and pin assembly should be replaced. Check the fit of wrist pin in connecting rod bushing by rocking the piston. This clearance should not exceed .0007 inch (.0178mm). Replace the wrist pin bushings if excessive clearance is found.

Wrist pin bushings should be reamed after being pressed into the connecting rods. Wrist pin clearance is between .5314 - .5317 inch (13.500 - 13.505mm). Install new wrist pin lock wires.

Check the ring gap with rings positioned in cylinder bores and ﬁt of piston in ring grooves. Refer to Figure 12 for correct gap and groove clearances speciﬁcations.

7.4. CRANKSHAFT

Check crankshaft threads, keyways, tapered ends and all machined and ground surfaces for wear, scores or damage. Standard crankshaft journals are 1.1250 - 1.1241 inch (28.575 - 28.552mm) diameter. If the crankshaft journals are excessively scored or worn or out-of-round and cannot be reground, the crankshaft must be replaced. Connecting rod bearing inserts are available in .010 - .020 inch (.254 - .508mm) and .030 inch (.762mm) undersizes for compressors with reground crankshafts.

Main bearing journals must be maintained so the ball bearings are a snug fit or so that no more than .0065 inch (.1651mm) clearance exists between the precision sleeve main bearing and the main bearing journals on the crankshaft. In crankshafts fitted with oil seal rings, the oil seal ring groove or grooves 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 through the crankshaft.

7.5. END COVER

Check end covers for cracks and external damage. If main bearings are installed in the end cover, check for excessive wear and ﬂat spots and replace them if required. The oil seals should be replaced using a press.

7.6. CONNECTING ROD BEARINGS

Used (old) bearing inserts must 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 journal and the connecting rod bearing must not be less than .0003 inch (.00762mm) or more than .0021 inch

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8. REPAIR

8.1. DISCHARGE VALVES, VALVE STOPS AND SEATS (FIGURE 13 )

Figure 13 Discharge Valve, Valve Stop and Seat

If the discharge valve seats merely show signs of slight wear, they can be dressed by using a lapping stone, grinding compound and grinding tool. If the discharge valve stops are to be replaced, an application of a sealer is required, such as Loctite Retaining Compound #75. Be sure that the press ﬁt between the discharge valve stop outside diameter and the valve stop bore in the cylinder head is a minimum of .0008 inch (.02032mm) and a maximum of .0028 inch (.07112mm). If this ﬁt cannot be maintained, a new cylinder head body must be used. Be sure to completely support the outside top of the cylinder head casting while pressing in the replacement stops. Install the new discharge valve springs and valves. Screw in the discharge valve seats. Discharge valve travel should be between .041 - .057 inch (1.0414 - 1.4478mm).

8.2. DISCHARGE VALVES LEAK AGE TEST

To test for leakage by the discharge valves, apply 100 psi air pressure through the cylinder head discharge port and apply a soap solution to the discharge valves and seats. A slight leakage in the form of soap bubbles is permissible. If excessive leakage is found, leave the air pressure applied and with the use of a

ﬁbre or hardwood dowel and a hammer, tap the discharge valves off their seats several times. This will help the valves to seat and should reduce the leakage. With the air pressure still applied at the discharge port of the cylinder head, check for leakage around the discharge valve stops exposed on the top of the cylinder head casting. No leakage is permitted.

8.3. INLET VALVES AND SEATS

Inlet valves and springs should be replaced. If the inlet valve seats show signs of slight nicks or scratches, they can be redressed with a ﬁne piece of emery cloth or by lapping stone, grinding compound and grinding tool. If the seats are damaged to the extent that they cannot be reclaimed, they must be replaced. The dimensions from the top of the cylinder block to the inlet valve seat should not exceed .113 inch (2.870mm) nor be less than .101 inch (2.565mm) (Figure 14 ).

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Figure 14 Inlet Valve and Seat

9. REASSEMBLE

NOTE – Al l ﬂange mounted compressors must be assembled without a gasket between the crankcase and ﬂange adapter and some compressors do n ot require gaskets on the end cover. Install the new crankcase gaskets only where they were removed during disassembly. Failure of the compressor would result if gaskets are used when not req uired.

1. On compressors which use a ball type main bearing, press the ball bearing onto the correct end of the crankshaft. Position the ball bearing and the crankshaft in the crankcase making sure the drive end of the crankshaft is positioned in the crankcase as marked before disassembly. Carefully press the crankshaft and ball bearing into the crankcase using an arbor press.

2. On compressors with a front ball bearing, place two small seal rings in the countersunk holes at the front of the crankcase, as well as an end cover gasket. Install the front end cover in proper position as marked before disassembly taking car e not to damage the new oil seal.

3. On compressors with a rear ball bearing, place two small seal rings in countersunk at the rear of the crankcase. In one application a gasket is used and in another a large O-ring is placed in the counterbore at the rear of the crankcase. These are in addition to the seal rings. Install the rear end cover in the proper position as marked before disassembly. On some compressors the area for the two small seal rings has been increased slightly and the seal ring thickness increased. When the thicker O-rings are used, a retaining ring will also be used as shown in Figure 15 .

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Figure 15 Use of Retaining Ring

4. On compressors with a sleeve bearing either front or rear, place the two small seal rings in the countersunk holes in the crankcase. Where seal rings are used, an end cover gasket MUST NOT be used. Place the O-ring seal in the groove around the ﬂange adapter or the end cover, and af ﬁx the thrust washer.

5. Install the ﬂange adapter or end cover in the proper position as marked before disassembly taking care not to damage the sleeve bearing.

6. Secure the ﬂange adapter, front or rear cover to the crankcase by tightening the capscrews to the following torque values.

a. 7/16‟ Capscrews, Cast Iron Flange Adapter, 38 - 45 ft-lbs. (51.5 - 61 N•m)

b. 7/16‟ Capscrews, Cast Aluminum End Cover, 25 - 30 ft-lbs. (34 - 40.7 N•m)

c. 5/16‟ Capscrews or Stud and Nut, All End Covers, 15 - 18 ft-lbs. (20.3 - 24.4 N•m)

d. 7/16‟ Capscrews, Through Drive Compressor with Cast Iron End Covers, 25 - 30 ft-lbs. (34 - 40.7 N•m)

7. If new wrist pins are being installed, they should be pressed into the connecting rods so that the oil hole in the bushing lines up with the one in the rod.

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8. The new bushings should be reamed or honed to provide .0001 - .0006 inch (.00254 - .01524mm) clearance on the wrist pin. Position the connecting rod in the piston and press in the wrist pin. Some compressors will have the wrist pin secured in the piston by a lock wire extending through matching holes in wrist pin and piston boss, anchored in a hole in the side wall of the piston. If the original pistons are used, the wrist pin must be pressed in so the hole in the wrist pin aligns with that of the piston. Secure same by inserting the new lockwire through the hole in piston and wrist pin and lock the wire by snapping the short 90 degree section into the lockwire hole in the bottom of the piston.

Later design compressors will have the wrist pin secured by Teflon buttons in either end of the wrist pin, allowing the wrist pin to float. The Teflon buttons may be used with either new or old wrist pins.

9. The late design pistons have two rings above the wrist pin and one below. Install piston rings in the correct location with ring pipmarks up. Stagger the position of ring gaps. Prelubricate piston, rings, wrist pin and connecting rod bearings with clean engine oil before installing them in the compressor.

10. Remove connecting rod bearing cap from connecting rod. Turn crankshaft so that one of the connecting rod journals is in the downward center position. Install crankshaft journal rod bearing in connecting rod and rod cap.

11. Stagger piston rings so that the ring gaps are 120 degrees apart. Apply engine oil to rings, piston and wrist pin. Use ring compressor and compress piston rings.

12. Install piston/rod assembly into correct cylinder (the one it was removed from). Tap ring compressor

ﬂush with block.

13. Use hammer handle and tap piston into cylinder bore, guiding rod/bearing onto crankshaft journal. 14. Attach bearing cap to connecting rod making sure that a lock strap is positioned on the cap. Tighten the

rod bolts to 120 - 150 inch pounds or 10 - 12 ft-lbs. (13.5 - 16.3 N•m). Bend lock strap prongs against hex head of bolts.

15. Install remaining piston and connecting rod in the same manner.

16. A new unloader kit (Figure 16 ) should be used when reassembling the compressor. The pistons in the kit are prelubricated with a special lubricant and require no further lubrication. Install unloader pistons in their bores taking care not to cut O-ring. Position unloader plungers in their guides and slip them in and over the tops of the pistons. Install unloader spring seat in crankcase inlet cavity. A small hole is drilled in crankcase for this purpose. Position the saddle between unloader piston guides so its forks are centered on guides. Install unloader spring making sure it seats over the spring seats both in crankcase and on saddle. Install inlet valve guides, then position valves in their guides. There should be a loose sliding ﬁt between the guides and valves.

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Figure 16 Unloader Mechanism

17. Install the inlet valve springs in the cylinder head by applying a turning motion to the spring after it is in the head. The turning motion should dig the spring wire into the spring seat in the bottom of the spring bore in the head. Should this procedure fail after repeated attempts, use a very small quantity of grease to hold them in place, just enough to keep the springs from falling out. Place the cylinder head gasket on the cylinder block. Carefully align the cylinder head assembly on the block and install the capscrews, tightening them evenly to a torque of 25 - 30 ft-lbs. (34 - 40.7 N•m).

18. Position the base plate or base adapter gasket on the crankcase and install the base plate adapter as marked before disassembly. Tighten the six capscrews securing the cast iron base adapter evenly to a torque of 38 - 45 ft-lbs. (51.5 - 61 N•m) and 12 - 16 ft lbs. (16.26 - 21.69 N•m) for base plate or aluminum cover.

10. TESTING

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 ef ﬁciency or build-up test can be run which is not too dif ﬁcult. An engine lubricated compressor must be connected to an oil supply line of at least 15 psi during the test and an oil return line must be installed to keep the crankcase drained.

Connect to the compressor discharge port a reservoir with a volume of 1500 cu. in. including the volume of connecting line. With the compressor operating at 2100 RPM, the time required to raise the reservoir’s pressure from 85-100 psi should not exceed 7 seconds. During this test, the compressor should be checked for gasket leakage and noisy operation as well as unloader operation and leakage.

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11. TROUBLESHOOTING

The following is a listing of the most commonly experienced compressor deﬁciencies and their probable causes. Table 1 Troubl eshooting Chart

Condition Possible Cause Remedy

Compressor passes

excessive oil as evidenced by presence of oil at exhaust ports of valving or seeping from air strainer.

Restricted air intake. Check engine or compressor air cleaner and replace if necessary. Check compressor air inlet line for kinks. Recommended maximum air inlet restriction is 25‟ of water.

Restricted oil return (to engine).

Check for excessive bends, kinks, and restrictions in the oil return line.

Poorly ﬁltered inlet air. Check for damaged, defective or dirty air ﬁlter on engine or compressor.

Insuf ﬁcient compressor cooling (compressor runs hot).

For air-cooled compressor or air-cooled portions of the compressor:

A. Remove accumulated grease, grime, or dirt from the cooling ﬁns. Replace components found damaged.

B. Air-cooled compressors should not be used on engines equipped with fan clutches.

For water-cooled compressor or water-cooled portions of the compressor

A. Check for proper coolant line sizes. Minimum recommended size is 1/2‟ O.D.

tubing.

B. Check the coolant ﬂow through the compressor.

C. Water temperature should not exceed 200°F.

Contaminants not being regularly drained from system reservoirs.

Check reservoir drain valves to insure that they are functioning properly. It is recommended that the vehicle should be equipped with functioning automatic drain valves, or have all reservoirs drained to zero psi daily.

Compressor runs loaded an excessive amount of time.

Check for systems leaks and repair. Excessive engine

crankcase pressure.

Test for excessive engine crank-case pressure and replace or repair crankcase ventilation components as necessary. (An indication of crankcase pressure is a loose or partially lifted dipstick.)

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Table 1 Troubleshooting Chart (cont.)

Excessive engine oil pressure.

Check the engine oil pressure with a test gauge and compare the reading to the engine speciﬁcations. Minimum oil supply line size is 1/4‟ O.D. tubing.

Faulty compressor. Replace or repair the compressor only after making certain none of the preceding installation defects exist.

Noisy compressor operations

Loose drive gear or pulley. If the compressor crankshaft surface or its keyway is damaged, it is an indication of loose drive components. If damage to the compressor crankshaft is detected, replace the compressor or the crankshaft. When installing the drive gear or pulley, torque the crankshaft nut to 100 foot pounds. DO NOT BACK OFF THE CRANKSHAFT NUT TO ALIGN THE COTTER PIN AND CASTELLATED NUT. (Some compressors do not use castellated nuts.) DO NOT USE IMPACT WRENCHES. Excessively worn drive

coupling or gears.

Replace as necessary. (Non-metallic gears should be replaced when the compressor is changed.) 501 drive gear should be metal type on Detroit Diesel engine.

Compressor cylinder head or discharge line restrictions.

Inspect the compressor discharge port and discharge line for carbon build-up. If carbon is detected, check for proper cooling to the compressor. Inspect the discharge line for kinks and restrictions. Replace discharge line as necessary.

Worn or burned out bearings.

Check for clean engine oil and proper oil pressure in the compressor. Minimum required oil pressure: 5 psi engine idling, 15 psi

maximum governed engine rpm. Check for excessive oil temperature should not exceed 240°F.

Faulty compressor. Replace or repair the compressor after determining none of the preceding installation defects exist.

(26)

Excessive build-up and recovery time. Compressor should be capable of building air system from 85 - 100 psi in 40 seconds with engine at full governed rpm. Minimum compressor performance is certiﬁed to meet Federal requirements by the vehicle manufacturer. Do not downsize the original equipment compressor.

Dirty air induction ﬁlter. Inspect engine or compressor air ﬁlter and replace if necessary.

Restricted induction line. Inspect the compressor air induction line for kinks and restrictions and replace as necessary.

Restricted discharge line or compressor discharge cavity.

Inspect the compressor discharge port and line for restrictions and carbon build-up. If a carbon build-up is found, check for proper compressor cooling. Replace faulty sec tions of the discharge line.

Slipping drive components. Check for faulty drive gears and couplings and replace as necessary. Check the condition of drive belts and replace or tighten, whichever is appropriate.

Excessive air system leakage.

Build system pressure to governor cutout and allow the pressure to stabilize for one minute. Using the dash gauge, note the system pressure and the pressure drop after two minutes.The pressure drop should not exceed: A. 2 psi in each reservoir for a single vehicle.

B. 6 psi in each reservoir for a tractor and trailer.

C. 8 psi in each reservoir for a tractor and 2 trailers.

(27)

Sticking unloader pistons and plungers.

Check the operation of the unloading pistons in the inlet cavity of the compressor. Both pistons should have the plunger ﬂanges resting on the inlet cavity ﬂoor when the compressor is loaded (pumping air). If the pistons and plunger are not fully retracted, check for proper operation of the compressor air governor. If the governor is operating properly, replace the unloader pistons and plungers and inspect their bores in the cylinder block. Clean and lubricate as necessary. Inspect for bent, kinked or blocked tubing leading to or from the governor.

Faulty compressor. Replace or repair the compressor after determining none of the preceding installation defects exist.

Compressor fails to unload Faulty governor or governor installation.

Test the governor for proper operation and inspect air lines to and from the governor f or kinks or restrictions. Replace or repair the governor or its connecting air lines.

Faulty or worn unloader pistons or bores.

Inspect for worn, dirty or corroded unloader pistons and their cylinder block bores. Replace as necessary.

Compressor leaks oil Damaged mounting gasket. Check the compressor mounting bolt torque. If the mounting bolt torque is low, replace the compressor mounting gasket before retorquing the mounting bolts.

Cracked crankcase, cylinder block or end cover.

Visually inspect the compressor exterior for cracked or broken components. Cracked or broken crankcases or mounting ﬂanges can be caused by loose mountin g bolts. The end cover can be cracked by over-torquing ﬁtting or plugs installed in the end cover. Replace or repair the compressor as necessary.

Loose end cover or cylinder block capscrews.

Check the capscrew torques and tighten as necessary.

Loose oil supply or return line ﬁttings.

Check the torque of external oil line ﬁttings and tighten as necessary.

Porous compressor casting. Replace the compressor if porosity is found. Mounting ﬂange or end

cover, O-ring or gasket missing, cut, or damaged.

Replace as necessary.

Compressor constantly cycles (compressor remains unloaded for a very short time.)

Leaking compressor. Remove the compressor inlet air strainer or

ﬁtting. With the compressor unloaded (not compressing air), check for air leakage around the unloader pistons. Replace as necessary.

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Faulty governor. Test the governor for proper operation and repair or replace as necessary.

Excessive system leakage Test for excessive system leakage as instructed under Excessive build-up and recovery time, Remedy 5. Reduce leakage wherever possible.

Excessive reservoir contaminants.

Drain reservoirs. Compressor leaks coolant Improperly installed plugs

and coolant line ﬁttings

Check torque of ﬁttings and plugs and tighten as necessary. Over-torqueﬁttings and plugs can crack the head or block casting.

Freeze cracks due to improper anti-freeze strength.

Test anti-freeze and strengthen as necessary. Check coolant ﬂow through compressor to assure the proper anti-freeze mixture reaches the compressor.

Faulty compressor (porous castings).

If casting porosity is detected, replace the compressor.

Compressor head gasket failure

Restricted discharge line. Clear restriction or replace line.

Loose head bolts. Tighten evenly to a torque of 25 - 30 t-lbs. (34 - 40.7 N•m).

Faulty compressor or head gasket.

Check for rough or poorly machined head or block surfaces. Replace necessary components.

12. SPECIFICATIONS

12.1. COMPRESSOR DATA

Table 2 Compressor Data Chart

Number of cylinders 2

Bore Size 2.625 in.

Stroke 1.50 in.

Piston displacement at 1250 RPM 12 cu. ft.

Piston displacement per revolution 16.5 cu. in. Maximum recommended RPM (naturally aspirated) 3000

Minimum coolant ﬂow at maximum RPM 2.5 gal./min. Horsepower required at 3000 RPM against 100 PSI head

pressure

4.9 H.P.

Recommended minimum discharge line size 5/8 in. OD Copper Tube Recommended minimum oil return line size 5/8 in. OD Tubing

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Table 2 Compressor Data Chart (cont.)

Recommended minimum oil supply line size 1/4 in. OD Tubing Recommended minimum unloader line size 1/4 in. OD Tubing Recommended minimum inlet cavity line size (when

compressor is connected to engine air cleaner)

5/8 in. ID Tubing Recommended minimum coolant line size 1/2 in. OD Tubing Recommended maximum inlet air temperature 250°F

Recommended maximum discharge air temperature 400°F

(30)

12.2. MEASUREMENTS

Table 3 Measurements Chart

Application Inches Millimeters

Maximum Discharge Valve Travel .057 1.447

Crankcase with Ball Bearing Crankshaft Mains

O.D. of Bearing Race and I.D. of Case Clearance 0 - .0015 0 - .0381 Sleeve-Type Main Bearings-Difference Between O.D. of

Crankshaft and I.D. of Main Bearing Maximum

.0065 .1651

Cylinder Bore Out-of-Round Maximum .001 .0254

Cylinder Bore Taper Maximum .002 .0508

Oversized Pistons Available .010 .2540

.020 .5080

.030 .7620

Cylinder Bore to Piston Clearance .002 - .004 .0508 - .1016

Piston to Piston Pin Bushing Clearance Maximum .0007 .0177

New Reamed Piston Pin Bushing to Pin Clearance .5314 - .5317 13.498 - 13.505

Standard Crankshaft Journals 1.1250 - 1.1241 28.575 - 28.552

Oversized Rod Bearings Available .010 - .020 .254 - .508

.030 .762

Clearance Between Rod Journal and Rod Bearing

Not Less Than .0003 .00762

Not More Than .0021 .05334

Discharge Valve Stop Outside Diameter and Valve Stop Bore in Cylinder Head is

Minimum .0008 .02032

Maximum .0028 .07112

Discharge Valve Travel .041 - .057 1.0414 - 1.4478

Inlet Valve Seats Top of Cylinder Block to Inlet Valve Seat

Maximum .113 2.870

Air Compressor Bendix Tu-flo 501 (1)

SERVICE MANUAL SECTION

SERVICE MANUAL SECTION

AIR

AIR COMPRESSOR:

COMPRESSOR: B

BENDIX

ENDIX TU-FLO

TU-FLO 501

501

V

Vendor:

endor: BEN

BENDI

DIX

X

Model:

Model: 20

2000

00

Model:

Model: 30

3000

00

Model:

Model: 40

4000

00

Model:

Model: 70

7000

00

Model:

Model: 81

8100

00

Model:

Model: 82

8200

00

Model:

Model: 83

8300

00

V

Vendor Code:

endor Code: 04

04SBA

SBA

s04010, Formerly CTS-5145

s04010, Formerly CTS-5145

03/31/1996

03/31/1996

Table of Contents

Table of Contents

DESCRIPTION

1. OPERATION

1.1. INTAKE A ND COMPRESSION OF AIR (LOADED)

1.2. NOT COMPRESSING AIR (UNLOADED)

2. LUBRICATION

3. COOLING

4. MAINTENANCE

4.1. AIR STRAINER (FILTER)

4.2. POLYURETHANE SPONGE STRAINER (FIGURE 5 )

4.3. DRY ELEMENT — PLEATED PAPER AIR STRAINER (FIGURE 6 )

4.4. COMPRESSORS WITH INTAKE ADAPTERS (FIGURE 7 )

4.5. EVERY 50,000 MILES (80,000 KM) OR 6 MONTHS

4.6. EVERY 200,000 MILES (322,000 KM) OR 24 MONTHS

4.7. OPERATION TESTS

4.8. AIR LEAKAGE TESTS

5. REMOVE

6. DISASSEMBLE

7. CLEAN AND INSPECT

7.1. CYLINDER HEAD

7.2. CRANKCASE

7.3. PISTONS

7.4. CRANKSHAFT

7.5. END COVER

7.6. CONNECTING ROD BEARINGS

8. REPAIR