SD-01-333 Bendix® Tu-Flo® 550 Air Compressor DISCHARGE VALVE STOP UNLOADER COVER AIR DISCHARGE WATER OUTLET DISCHARGE VALVE WATER INLET DISCHARGE VALVE SEAT AIR INLET CRANKCASE DISCHARGE VALVE SPRING PISTON RINGS GOVERNOR MOUNTING PAD CRANKCASE PISTON CONNECTING ROD CRANKSHAFT ® PIECE NO.
UNLOADER COVER PLATE AIR DISCHARGE AIR DISCHARGE WATER AIR INLET WATER WATER GOVERNOR FIGURE 1 - CYLINDER HEAD CAT MACK (MACK STYLE) MACK EXTENDED MACK "FOXHEAD" CUMMINS DETROIT DIESEL CAT BASE MOUNT FIGURE 2 - FLANGE CONFIGURATIONS Various mounting and drive configurations, as shown in Figure 2, are supplied as required by the vehicle engine designs. A nameplate identifying the compressor piece number and serial number is attached to the side of the crankcase. (Reference Figure 3.
AIR DISCHARGE PORT DISCHARGE PORT GOVERNOR PORT UNLOADER PISTON AIR INLET PORT AIR INLET PORT DISCHARGE VALVE CLOSED INLET VALVE OPEN GOVERNOR PORT DISCHARGE VALVE CLOSED INLET VALVE HELD OPEN BY UNLOADER PISTON PISTON MOVING DOWN FIGURE 4 - OPERATIONAL-LOADED (INTAKE) AIR DISCHARGE PORT FIGURE 6 - OPERATIONAL-UNLOADED GOVERNOR PORT force the pistons upward and the inlet valves return to their seats. Compression is then resumed.
The Air Brake Charging System supplies the Discharge Line Optional “Ping” Tank Air Dryer 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.
2. Naturally aspirated Engine Air Cleaner - Compressor inlet is connected to the engine air cleaner or the vacuum side (engine air cleaner) of the supercharger or turbocharger. 3. Pressurized induction - Compressor inlet is connected to the pressure side of the supercharger or turbocharger. OIL INLET See the tabulated technical data on page 14 of this manual for specific requirements for numbers 2 and 3 above.
COMPRESSOR TURBOCHARGING PARAMETERS POLYURETHANE SPONGE STRAINER Air entering the compressor inlet during the loaded cycle must not exceed 250 degrees Fahrenheit (121 degrees Celsius). A metal inlet line is suggested to help meet this parameter. The following compressor crankshaft rotative speed and inlet pressure relationships may not be exceeded. Crankshaft Maximum Compressor R.P.M. Every month, 150 operating hours or 5,000 miles, whichever occurs first, remove and wash all of the parts.
INTAKE ADAPTER When the engine air cleaner is replaced: Some compressors are fitted with compressor intake adapters, which allow the compressor intake to be connected to the engine air induction system. 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.
speed), and record the time taken to raise the system pressure a selected range (for example, from 90 to 120 psi, or from 100 to 120 psi, etc.) and record it in the vehicle’s maintenance files. Subsequent build-up times throughout the vehicle’s service life can then be compared to the first one recorded. (Note: the 40 second guide in the test above does not apply to this build-up time.
material (5) from the cover plate, cylinder head and crankcase. 1. Remove the unloader pistons (7), o-rings (6) and springs (8). 2. Inspect the unloader piston bushings (9) for nicks, wear, corrosion and scoring. It is recommended that the compressor be replaced if it is determined that the unloader bushing is damaged or worn excessively. Before disassembling the discharge valve mechanism, measure and record the discharge valve travel (from closed to completely open). 3.
2 3 1 23 23 4 5 24 25 6 7 CYLINDER HEAD 24 8 26 9 27 23 24 25 15 16 17 18 10 11 12 13 14 36 19 CRANKCASE BASE MOUNT 28 35 24 37 33 32 30 29 34 32 42 44 38 NAMEPLATE 20 39 40 19 CRANKCASE 32 BALL BEARING (MACK EXTENDED FLANGE) 31 32 FLANGE MOUNT 20 21 ITEM QTY 1 6 2 4 3 4 4 1 5 1 6 2 7 2 8 2 9 2 10 2 11 2 12 2 13 2 14 2 15 2 10 DESCRIPTION Cylinder Head Cap Screws Unloader Plate Cap Screws Unloader Plate Lock Washers Unloader Plate Unloader Plate Gasket O-ring Unloader Spring Unl
END COVERS PISTON RINGS Check for cracks and external damage. If the crankshaft main bearing (32) is installed in the end cover (34), check for excessive wear and flat spots and replace if necessary. Check the pistons for scores, cracks or enlarged ring grooves; replace the pistons if any of these conditions are found. Measure each piston with a micrometer in relation to the cylinder bore diameter to be sure the diametrical clearance is between .002 in. minimum and .004 in. maximum.
with a special lubricant piece number 239379 and need no additional lubrication. Install the springs and unloader pistons in their bores being careful not to cut the o-rings. Install the unloader cover gasket and unloader cover and secure the cover cap screws. Tighten the cap screws to 175-225 in. lbs. in a crossing pattern after first snugging all screws. INSTALLING CRANKSHAFT Press new sleeve bearings in the end cover and crankcase.
PISTONS AND CONNECTING RODS If the pistons are to be replaced ensure that the correct pistons are being installed. Note that the pistons for the Tu-Flo® 550 compressor are similar to those of other Bendix compressor models but may be identified by the piston diameter and the distance to the center of the wrist pin from the top of the piston as shown in Figure 13. PISTON RINGS Check each ring end gap in a cylinder bore before installation.
Connect to the compressor discharge port, a reservoir with a volume of 1500 cubic inches, including the volume of the connecting line. With the compressor operating at 2100 R.P.M., the time required to raise the reservoir(s) pressure from 85 psi to 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.
COMPRESSOR TROUBLESHOOTING IMPORTANT: The troubleshooting contained in this section considers the compressor as an integrated component of the overall air brake charging system and assumes that an air dryer is in use. The troubleshooting presented will cover not only the compressor itself, but also other charging system devices as they relate to the compressor. WARNING! PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH: 9.
Appendix A Advanced Troubleshooting Guide for Air Brake Compressors The guide consists of an introduction to air brake charging system components, a table showing recommended vehicle maintenance schedules, and a troubleshooting symptom and remedy section with tests to diagnose most charging system problems. INDEX Symptom Page Number Air Symptom Page Number Coolant Air brake charging system: Slow build (9.0) .....................................A-9-10 Doesn’t build air (10.0) .........................
Introduction to the Air Brake Charging System Powered by the vehicle engine, the air compressor builds the air pressure for the air brake system. The air compressor is typically cooled by the engine coolant system and lubricated by the engine oil supply.
Table A: Maintenance Schedule and Usage Guidelines Regularly scheduled maintenance is the single most important factor in maintaining the air brake charging system. Vehicle Used for: No. of Axles Column 1 Column 2 Typical Compressors Spec'd Discharge Line (See footnote 7) I.D. Length 1/2 in. 6 ft. Column 3 Recommended Air Dryer Cartridge Replacement1 Column 4 Recommended Reservoir Drain Schedule2 Column 5 Acceptable Reservoir Oil Contents3 at Regular Drain Interval e.g.
Air Brake Charging System Troubleshooting Look for: How to use this guide: Find the symptom(s) that you see, then move to the right to find the possible causes (“What it may indicate”) and remedies (“What you should do”). Review the warranty policy before performing any intrusive compressor maintenance. Unloader or cylinder head gasket replacement and resealing of the bottom cover plate are usually permitted under warranty. Follow all standard safety procedures when performing any maintenance.
Symptom: What it may indicate: What you should do: 2.0 Oil on the Outside of the Compressor Engine and/or other accessories leaking onto compressor. Find the source and repair. Return the vehicle to service. 2.1 Oil leaking at compressor / engine connections: (a) Leak at the front or rear (fuel pump, etc.) mounting flange. Repair or replace as necessary. If the mounting bolt torques are low, replace the gasket. (b) Leak at air inlet fitting. Replace the fitting gasket.
Symptom: What it may indicate: 4.0 Oil in Supply or Service Reservoir (air dryer installed) (If a maintained Bendix PuraGuard® system filter or Bendix® PuraGuard QC™ oil coalescing filter is installed, call 1-800-AIR-BRAKE (1-800-247-2725) and speak to a Tech Team member.) ® What you should do: Maintenance (a) If air brake charging system maintenance has not been performed.
Symptom: 4.0 Oil in Supply or Service Reservoir* (air dryer installed) (continued) What it may indicate: What you should do: Temperature (e) Air compressor discharge and/or air dryer inlet temperature too high. Check temperature as outlined in Test 3 on page A-14. If temperatures are normal go to 4.0(h). Inspect coolant line. Replace as necessary (I.D. is 1/2"). (f) Insufficient coolant flow. Inspect the coolant lines for kinks and restrictions and fittings for restrictions. Replace as necessary.
Symptom: 4.0 Oil in Supply or Service Reservoir* (air dryer installed) (continued) What it may indicate: What you should do: Other (cont.) (i) Poorly filtered inlet air (poor air quality to compressor). Check for leaking, damaged or defective compressor air inlet components (e.g. induction line, fittings, gaskets, filter bodies, etc.). Repair inlet components as needed. Note: Dirt ingestion will damage compressor and is not covered under warranty. Inspect the engine air cleaner.
Symptom: What it may indicate: 6.0 Excessive oil consumption in engine. A problem with engine or other engine accessory. 7.0 Oil present at air dryer cartridge during maintenance. Air brake charging system is functioning normally. What you should do: See engine service manual. The engine service manual has more information. Oil shown leaking from an air dryer cartridge. Air dryers remove water and oil from the air brake charging system. A small amount of oil is normal.
Symptom: 9.0 Air brake charging system seems slow to build pressure. (continued) What it may indicate: (f) Restricted discharge line. (f) Dash gauges. Kinked discharge line shown. Engine Oil Quality Inadequate oil change intervals, the formulation of the oil and/or the quality of oil filter used can all lead to poor oil quality. These can increase the rate at which carbon builds up in the discharge line. Bendix recommends oil soot (solids) be maintained at less than 3%.
Symptom: 10.0 Air charging system doesn’t build air. What it may indicate: (a) Governor malfunction*. Go to Test 4 on page A-15. (b) Restricted discharge line. See 9.0(f). (c) Air dryer heater malfunction: exhaust port frozen open. Replace air dryer heater. (d) Compressor malfunction. Replace the compressor only after making certain the preceding conditions do not exist.
Symptom: 12.0 Air dryer safety valve releases air. Air dryer safety valve Technician removes governor. 13.0 Reservoir safety valve releases air 14.0 Air dryer doesn’t purge. (Never hear exhaust from air dryer.) 15.0 Compressor constantly cycles (compressor remains unloaded for a very short time.) 28 A-12 What it may indicate: What you should do: (a) Restriction between air dryer and reservoir. Inspect delivery lines to reservoir for restrictions and repair as needed.
Symptom: 16.0 Compressor leaks air Testing for leaks with soap solution. 17.0 Compressor leaks coolant 18.0 Noisy compressor (Multi-cylinder compressors only) What it may indicate: What you should do: (a) Compressor leaks air at connections or ports. Check for leaking, damaged or defective compressor fittings, gaskets, etc. Repair or replace as necessary. (b) Compressor unloader mechanism malfunction. Go to Test 6 on page A-15. (c) Damaged compressor head gasket(s).
Tests Test 1: Excessive Oil Leakage at the Head Gasket Exterior leaks at the head gasket are not a sign that oil is being passed into the air charging system. Oil weepage at the head gasket does not prevent the compressor from building air. Observe the amount of weepage from the head gasket. If the oil is only around the cylinder head area, it is acceptable (return the vehicle to service), but, if the oil weepage extends down to the nameplate area of the compressor, the gasket can be replaced.
Tests (continued) Test 4: Governor Malfunction 1. Inspect control lines to and from the governor for restrictions (e.g. collapsed or kinked). Repair as necessary. 2. Using a calibrated external gauge in the supply 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. Test 5: Governor Control Line 1.
Appendix B: Information about the BASIC™ Test Kit (Bendix P/N 5013711) Service writer records info - including the number of days since all air tanks were drained - and fills out symptom checklist. Technician inspects items. days Bendix® Air System Inspection Cup (BASIC™) Test Information START BASIC TEST Park vehicle on LEVEL ground. Chock wheels, drain air from system. Drain contents of ALL air tanks into BASIC™ cup Is there less than one unit of liquid? Vehicle OK. Return vehicle to service.
Appendix B continued: Information about the BASIC™Test Kit (Bendix P/N 5013711) ® Filling in the Checklist for the Bendix Air System Inspection Cup (BASIC™) Test Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer.
Appendix B continued: Information about the BASIC™Test Kit (Bendix P/N 5013711) ® Filling in the Checklist for the Bendix Air System Inspection Cup (BASIC™) Test Note: Follow all standard safety precautions. For vehicles using a desiccant air dryer. STEP C - How to Use the BASIC™ Test 1. Record days since air tanks were last drained. 2. Record amount of oil found: The Technician uses the chart (label) on the BASIC™ test cup to help decide the action to take, based on the amount of oil found.
Appendix C Technical Bulletin Bulletin No.: TCH-008-021 Page: 1 of 2 Subject: Air Effective Date: 11/1/92 Brake System - Cold Weather Operation Tips As the cold weather approaches, operators and fleets alike begin to look to their vehicles with an eye toward “winterization”, and particularly what can be done to guard against air system freeze-up. Here are some BASIC™“Tips” for operation in the cold weather.
Appendix C: Continued Bulletin No.: TCH-008-021 Page: 2 of 2 Effective Date: 11/1/92 High Duty Cycle Vehicles (City Transit Coaches, Refuse Haulers, Etc.) The maximum discharge line length is 16 feet. Length 10-16 ft. ½ in. I.D. min. Other Requirements None If the discharge line length must be less than 10 feet or greater than 16 feet, contact your local Bendix representative.
Appendix D Technical Bulletin Bulletin No.: TCH-008-022 Page: 1 of 1 Subject: Additional Effective Date: 1/1/1994 Cold Weather Operation Tips for the Air Brake System Last year we published Bulletin PRO-08-21 which provided some guidelines for “winterizing” a vehicle air brake system. Here are some additional suggestions for making cold weather vehicle operation just a little more bearable.
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