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A convenient method to indicate the above relationship is to
use a metal scribe to mark the parts with numbers or lines.
Do not use a marking method that can be wiped off or
obliterated during rebuilding, such as chalk. Remove all
compressor attachments such as governors, air strainers
or inlet fittings, discharge fittings and pipe plugs.

Cylinder Head

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

The discharge valve stops should be inspected for wear
and replaced if excessive peening has occurred. To
determine if excessive peening has occurred, measure the
discharge valve travel. Discharge valve travel must not exceed
.057 inches. To remove the discharge valve stops, support
the machined surface of the cylinder head on an arbor press
bed and gently press the stops from the top of the head and
out the bottom. Be sure to allow sufficient clearance for the
stops between the press bed and the bottom of the cylinder
head. The valve stop bores in the cylinder head must be
inspected for excessive scoring. A new head body must be
used if scoring is excessive. Discard the inlet valves and
springs, the discharge valves and springs and the discharge
valve seats if defective.

Crankcase Base Plate or Adapter

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

Connecting Rod Assemblies

(Note:

Before removing the connecting rods, mark each
connecting rod and its cap. Each connecting rod is
matched to its own cap for proper bearing fit, and
these parts must not be interchanged.)

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

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

Crankcase

Remove the key or keys from the crankshaft and any burrs
from the crankshaft where the key or keys were removed.

(Note:

Through Drive Compressors may have a crankshaft
key at both ends.)

Remove the four cap screws securing front or drive-end end
cover or flange adapter. Remove the end cover, taking care
not to damage the crankshaft oil seal or front main bearing,
if any. Remove both of the small seal rings from the
crankcase, and the o-ring from around the front end cover.
Remove the four cap screws securing the rear end cover
and remove the rear end cover taking care not to damage
the rear main bearing, if any. Remove both of the small seal
rings from the crankcase and the o-ring from around the end
cover. If the compressor has ball type main bearings, press
the crankshaft and ball bearings from the crankcase, then
press the ball bearings from the crankshaft. Remove the
unloader spring, spring saddle, and spring seat from the
inlet cavity of the crankcase, using long nose pliers. Remove
the unloader plungers and guides. Cover the inlet cavity with
a shop rag and apply air pressure to the governor mounting
pad unloader port to blow the unloader pistons out of their
bores and into the inlet cavity.

CLEANING OF PARTS

General

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

Cylinder Head

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

Crankcase

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

Oil Passages

Thoroughly clean all oil passages through the crankshaft,
crankcase, end covers, and base plate or base adapter.
Inspect the passages with a wire to be sure. Blow the
loosened foreign matter out with air pressure.

Summary of Contents for TU-FLO 501

Page 1: ... The crankcase is a one piece casting combining the cylinder block and the crankcase The upper portion of the casting houses the cylinder bores and inlet valving and the lower portion the crankshaft and main bearings Various mounting and drive configurations required by the numerous vehicle engine designs are obtained by bolting different mounting flanges end covers and base adapters to the crankc...

Page 2: ...into the cylinder on the down stroke 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 the upward stroke and compressed air then flows by the open discharge valve into the discharge line and on to the reservoirs see Fig 5 As the piston reaches the top of its stroke and starts down the discharge valve spr...

Page 3: ...mpressor Discharge Line Optional Ping Tank Optional Bendix PuraGuard QC Oil Coalescing Filter The Air Brake Charging System supplies the compressed air for the braking system as well as other air accessories for the vehicle The system usually consists of an air compressor governor discharge line air dryer and service reservoir from fittings connections lines chambers or valves etc Refer to TableAi...

Page 4: ... Flo 501 compressors are connected to the engine s pressurized oil system a continuous flow of oil is provided to the compressor which is eventually returned to the engine Oil is fed into the compressor in various ways for example through the rear end cover the drive end of the crankshaft or through the front flange adapter An oil passage in the crankshaft conducts pressurized oil to the precision...

Page 5: ...ers which allow the compressor intake to be connected to the engine air cleaner In this case the compressor receives a supply of clean air from the engine air cleaner When the engine air filter is changed the compressor intake adapter should be checked If it is loose remove the intake adapter clean the strainer plate if applicable and replace the intake adapter gasket and reinstall the adapter sec...

Page 6: ... by removing the discharge line applying shop air back through the discharge port and listening for escaping air Also the discharge valves and the unloader pistons can be checked for leakage by building up the air system until the governor cuts out then stopping the engine With the engine stopped listen for escaping air at the compressor intake To pinpoint leakage if noted apply a small quantity o...

Page 7: ...g caps on their respective connecting rods Remove the piston rings from the pistons If the pistons are to be removed from the connecting rods remove the wrist pin lock wires or teflon plugs and press the wrist pins from the pistons and connecting rods If the pistons are removed from the rod inspect the bronze wrist pin bushing Press out and replace the bushing if it is excessively worn See inspect...

Page 8: ...replaced Check the unloader bore bushings to be sure they are not worn rusted or damaged If these bushings are to be replaced they can be removed by running a 1 8 in pipe thread tap into the bushing and inserting a 1 8 in pipe threaded rod and pulling the bushing straight up and out Do not use an easy out for removing these bushings If the inlet valve seats are worn or damaged so they cannot be re...

Page 9: ...rings and valves Screw in the discharge valve seats Discharge valve travel should be between 041 in to 057 in To test for leakage by the discharge valves apply 100 pounds of 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...

Page 10: ...st pin Pistons installed in compressors manufactured prior to November 1976 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 and secure same by insert...

Page 11: ...hose tools 4 If the work is being performed on the vehicle s air brake system or any auxiliary pressurized air systems make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle If the vehicle is equipped with an AD IS airdryersystemoradryerreservoirmodule be sure to drain the purge reservoir 5 Following the vehicle manufacturer s recommendedprocedures deac...

Page 12: ...trol ATC the ATC function must be disabled ATC indicator lampshouldbeON priortoperforminganyvehicle maintenance where one or more wheels on a drive axle are lifted off the ground and moving TABULATED DATA 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 Min...

Page 13: ...y cycles 15 0 24 Leaks air 16 0 25 Safety valve releases air 11 0 23 Noisy 18 0 25 Reservoir Safety valve releases air 13 0 24 INDEX Air Coolant Engine Oil Compressor leaks coolant 17 0 25 Oil consumption 6 0 21 Oil Test Card results 1 0 16 Oil is present On the outside of the compressor 2 0 17 At the air dryer purge exhaust or surrounding area 3 0 17 In the supply reservoir 4 0 18 20 At the valve...

Page 14: ...ing in a temperate climate See Bendix and or other air dryer manufacturer guidelines as needed When the temperature of the compressed air that enters the air dryer is within the normal range the air dryer can remove most of the charging system oil If the temperature of the compressed air is above the normal range oil as oil vapor is able to pass through the air dryer and into the air system Larger...

Page 15: ...ck fire truck e g Line haul single trailer w o air suspension air over hydraulic brakes e g Line haul single trailer with air suspension school bus e g City transit bus refuse bulk unloaders low boys urban region coach central tire inflation 5 or less 5 or less 8 or less 12 or less Table A Maintenance Schedule and Usage Guidelines Recom mended Every Month Max of every 90 days Every Month Every 3 Y...

Page 16: ...REME CAUTION should be used to prevent personal injury resulting from contact with moving rotating leaking heated or electrically charged components 3 Do not attempt to install remove disassemble or assemble a component until you have read and thoroughly understand the recommended procedures Use only the proper tools and observe all precautions pertaining to use of those tools 4 If the work is bei...

Page 17: ...for the Bendix AD IS or AD IP air dryers or 5003838 for the Bendix AD 9 air dryer is available to redirect the air dryer exhaust 3 0 Oil at air dryer purge exhaust or surrounding area c 2 0 Oil on the Outside of the Compressor Find the source and repair Return the vehicle to service ð Repair or replace as necessary If the mounting bolt torques are low replace the gasket ð Replace the fitting gaske...

Page 18: ...range return the vehicle to service For vehicles with accessories that are sensitive to small amounts of oil consider a Bendix PuraGuard QC oil coalescing filter ð If outside the normal range go to Symptom 4 0 c Also see the Table A on page 15 column 3 for recommended air dryer cartridge replacement schedule Maintenance a ð Go to Test 2 on page 26 ð See Table A column 1 on page 15 for recommended ...

Page 19: ... inlet insulation may be added here or if the inlet fitting is a typical 90 degree fitting it may be changed to a straight or 45 degree fitting For more information on how to help prevent discharge line freeze ups see Bendix Bulletins TCH 08 21 and TCH 08 22 Appendix B Shorter discharge line lengths or insulation may be required in cold climates Temperature Other ð Check compressor air inlet line ...

Page 20: ...ines tests all air brake system pneumatic components need to be able to pass including minimum levels of tolerance to contamination 5 0 Oil present at valves e g at exhaust or seen during servicing Air brake system valves are required to tolerate a light coating of oil ð A small amount of oil does not affect SAE J2024 compliant valves ð Check that regular maintenance is being performed and that th...

Page 21: ...y be undersized for the application d Compressor unloader mechanism malfunction e Damaged compressor head gasket ð Using dash gauges verify that the compressor builds air system pressure from 85 100 psi in 40 seconds or less with engine at full governed rpm Return the vehicle to service ð Go to Test 2 on page 26 ð See Table A column 1 on page 15 for some typical compressor applications If the comp...

Page 22: ...to build pressure continued f Restricted discharge line ð If discharge line is restricted ð By more than 1 16 carbon build up replace the discharge line see Table A column 2 on page 15 for recommended size and go to Test 3 on page 26 ð By other restrictions e g kinks Replace the discharge line See Table A column 2 on page 15 for recommended size Retest for air build Return vehicle to service or if...

Page 23: ...Replace the discharge line See Table A column 2 on page 15 for recommended size ð The discharge line must maintain a constant slope down from the compressor to the air dryer inlet fitting to avoid low points where ice may form and block the flow If instead ice blockages occur at the air dryer inlet insulation may be added here or if the inlet fitting is a typical 90 degree fitting it may be change...

Page 24: ...n page 27 ð Go to Test 2 on page 26 ð Go to Test 5 on page 27 12 0 Air dryer safety valve releases air a Restriction between air dryer and reservoir b Air dryer safety valve malfunction c Air dryer maintenance not performed d Air dryer malfunction e Improper governor control line installation to the reservoir f Governor malfunction ð Inspect delivery lines to reservoir for restrictions and repair ...

Page 25: ...at the head gasket may indicate a downstream restriction such as a freeze up or carbon blockage and or could indicate a defective or missing safety valve Find blockage go to 9 0 f for details and then replace the compressor Do not re use the safety valve without testing See Symptom 12 0 a ð If casting porosity is detected replace the compressor 18 0 Noisy compressor Multi cylinder compressors only...

Page 26: ...t 2 Air Brake System and Accessory Leakage Caution The temperatures used in this test are not normal vehicle conditions Above normal temperatures can cause oil as vapor to pass through the air dryer into the air brake system This test is run with the engine at normal operating temperature with engine at max rpm If available a dyno may be used 1 Allow the compressor to build the air system pressure...

Page 27: ...ines to and from the governor for restrictions e g collapsed or kinked Repair as necessary 2 Using a calibrated external gauge in the supply reservoir service reservoir or reservoir port of the D 2 governor verify cut in and cut out pressures are within vehicle OEM specification 3 If the governor is malfunctioning replace it Tests continued Test 4 Governor Malfunction 2 Perform proper reservoir dr...

Page 28: ...28 NOTES ...

Page 29: ...an inspects items drained and f days Use Test 2 Air Leakage Use Test 2 Air Leakage NO Re test with the BASIC Test after 30 days NO did not know when last drained Was the number of days since last draining known YES number of days was known 30 90 days END TEST Bendix Air System Inspection Cup BASIC Test Information Appendix A Information about the BASIC Test Kit Bendix P N 5013711 If the number of ...

Page 30: ...q Excessive engine oil loss amount described ______________ Is the engine leaking oil q no q yes Is the compressor leaking oil q no q yes q Other complaint ______________________________________ q No customer complaint Checklist for Technician è The Service Writer fills out these fields with information gained from the customer The Service Writer also checks off any complaints that the customer ma...

Page 31: ...days is 30 60 days high air use or 30 90 days low air use è if oil level is at or below acceptance line for number of daysè if oil level is above acceptance line for number of days è System OK Return to service Otherwise è if the number of days is unknown or outside the limits above if oil level is at or below 30 day acceptance line è if oil level is above 30 day acceptance line è STOP TEST Stop i...

Page 32: ...some periods of extended engine idling can not be avoided Discharge Lines The discharge line should slope downward form the compressor discharge port without forming water traps kinks or restrictions Cross overs from one side of the frame rail to the other if required should occur as close as possible to the compressor Fitting extensions must be avoided Recommended discharge line lengths and insid...

Page 33: ...aily reservoir draining is eliminated through the use of an automatic drain valve periodic manual draining is still required Alcohol Evaporator or Injector Systems Check for proper operation of these systems by monitoring alcohol consumption for a few days Reference Service Data Sheet SD 08 2301 for the Bendix Alcohol Evaporator Too little means the system is not receiving adequate protection and ...

Page 34: ...arts of valves and melting or burning non metallic air lines WARNING THIS PRACTICE IS UNSAFE AND CAN RESULT IN VEHICLE FIRE 2 Do not introduce pour fluids into air brake lines or hose couplings glad hands Some fluids used can cause immediate and severe damage to rubber components Even methanol alcohol which is used in Alcohol Evaporators and Injectors should not be poured into air lines Fluids pou...

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Page 36: ...BW1421 2004 Bendix Commercial Vehicle Systems LLC All rights reserved 9 2004 Printed in U S A 36 ...

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