System Saver TWIN Air Dryer. Maintenance Manual 35 Revised 11-02

Transcription

1 System Saver TWIN Air Dryer Maintenance Manual 35 Revised 11-02

2 Service Notes This publication provides maintenance and service procedures for Meritor WABCO s System Saver TWIN air dryers. The information contained in this publication was current at the time of printing and is subject to revision without notice or liability. 1. You must understand all procedures and instructions before you begin maintenance and service procedures. 2. You must follow your company s maintenance and service guidelines. 3. You must use special tools, when required, to avoid serious personal injury and damage to components. Meritor WABCO uses the following notations to warn the user of possible safety problems and to provide information that will prevent damage to equipment and components. WARNING A WARNING indicates a procedure that you must follow exactly to avoid serious personal injury. NOTE: A NOTE indicates an operation, procedure or instruction that is important for proper service. A NOTE can also supply information that will help to make service quicker and easier. CAUTION A CAUTION indicates a procedure that you must follow exactly to avoid damaging equipment or components. Serious personal injury can also occur. T This symbol indicates that you must tighten fasteners to a specific torque. Visit Our Web Site Visit the Meritor WABCO website for additional product and service information: meritorauto.com Drivetrain Plus Technical Electronic Library (TEL) on CD The CD includes product and service information on Meritor s Drivetrain Plus component lineup. $20. Order TP How to Order Call Meritor s Customer Service Center at Copyright 2002 Meritor WABCO

3 Table of Contents Section 1: Introduction System Overview TWIN Support Documentation How the TWIN Air Dryer Works TWIN Air Drying Cycle System Components Air Dryer Parts Wiring Harness Options Standard Wiring Harness Wiring/Plumbing Kit for E-Type Compressor Section 2: Troubleshooting and Testing Routine Maintenance Troubleshooting the TWIN Air Dryer System Pressure Relief Valve Meritor WABCO TWIN Air Dryer Troubleshooting Guide System Tests Heater Resistance Leak Test Section 3: Installing Replacement Parts Desiccant Cartridge Left Piston Cover Left Piston Assembly Right Piston Cover Right Piston Assembly Charging Valve Assembly Solenoid and Armature Assembly Heater Assembly Purge Valve Assembly Outlet Check Valve Assembly Orifice Assembly Purge Silencer (Muffler) Air Dryer Assembly Appendix I: Glossary A Appendix II: Application Information General Requirements A Operating Environment Requirements Installation Instructions for Special Applications A Bulk-Unloading or Central Tire Inflation (CTI) Air Systems Installing a Back-Pressure Control Valve Holset E-Type Compressor Systems A Function Econ Valve A Econ Valve Operation Replacing the Econ and Check Valves on a Holset E-Type Compressor System Replacing the Solenoid Valve Installing a Turbo Cutoff Valve A Installation Instructions Vehicle Air System E A Quick-Reference Guide inside back cover

4 Notes

5 Section 1 Introduction Section 1Introduction System Overview This maintenance manual provides an overview of the Meritor WABCO System Saver TWIN Air Dryer. If you are servicing a Meritor WABCO System Saver Series Single Air Dryer, use Maintenance Manual 34. A typical Meritor WABCO System Saver TWIN installation is illustrated below. Figure 1.1. Figure 1.1 GOVERNOR COMPRESSOR INTAKE LINE UNLOADER PORT RESERVOIR TO GOVERNOR LINE SYSTEM SAVER TWIN AIR DRYER COMPRESSOR DISCHARGE LINE COMPRESSOR CONTROL (PURGE) PORT DRYER INLET PORT DRYER OUTLET PORT CHECK VALVE SYSTEM RESERVOIR SYSTEM RESERVOIR TO BRAKE SYSTEM SUPPLY TANK CHECK VALVE c TWIN Support Documentation TP-94104, Installing the Meritor WABCO System Saver TWIN Air Dryer, provides complete installation instructions for the TWIN Air Dryer. TP is shipped with all TWIN dryers. For additional copies, contact Meritor Customer Service at PB contains a complete listing of System Saver TWIN replacement parts. TP-9773 is a poster-size troubleshooting guide. It also illustrates the various components that make up the System Saver TWIN air dryer. TP is a pocket-size version of TP TP-9672, Air Dryer Application Guide, provides an in-depth look at System Saver TWIN air dryer applications. T-97106V ($20.00) is a 30-minute videotape covering application, maintenance and service information for System Saver TWIN air dryers. Literature and videos are available on our web site (meritorwabco.com) or call the ArvinMeritor Customer Service Center ( ) to order. How the TWIN Air Dryer Works TWIN air dryer cartridges contain desiccant material that filters and dries compressed air. The process begins when supply tank pressure drops below cut-in pressure (approximately 100 psi). When this happens, the governor turns the compressor on. The compressor sends air to the supply port of the dryer, and an air drying cycle begins. Revised Page 1

6 Section 1 Introduction TWIN Air Drying Cycle Figure 1.2 Figure Dryer Inlet 2 Dryer Outlet 3 Governor Port 4 Purge Valve b Air drying cycle begins Air enters the dryer at the supply port (Port 1) Air flows past piston in to the first (right) cartridge. Air flows through cartridge where it is dried; moisture and contaminants are filtered out through the desiccant material in the cartridge. Dry, clean air flows to the delivery port (Port 2) of the dryer for delivery to the supply tank. Some air is diverted to the second cartridge where it moves upward through the desiccant. This cleans and dries (regenerates) the desiccant. While the compressor is running, a mild flow of air will vent to atmosphere through the purge valve. 1 Dryer Inlet 2 Dryer Outlet Air drying cycle continues, cartridge functions reversed Incoming air enters the second (left) cartridge for drying and then flows to the delivery port. Small amount of dried air flows into the first (right) cartridge to regenerate desiccant. Alternating air drying cycles continue, one cartridge to the other, every 60 seconds as long as the compressor is running. Figure Governor Port 4 Purge Valve b Figure b 1 Dryer Inlet 2 Dryer Outlet b 3 Governor Port 4 Purge Valve b At 60 psi or greater, the air dryer switches cartridges every 60 seconds Switching is controlled by timer/solenoid. Pistons shift from right to left, reversing airflow pattern. A mild purge, or puff of air, can be heard at the purge valve at the time of shift. 1 Dryer Inlet 2 Dryer Outlet 3 Governor Port 4 Purge Valve Dryer purges Supply tank reaches cutout pressure. Governor unloads compressor. Governor supplies air to unloader port (Port 4) of dryer. Moisture and contaminants pass through purge valve and out of dryer. A burst of air occurs when dryer purges; airflow from purge valve ceases for duration of unloaded cycle. Page 2 Revised 11-02

7 Section 1 Introduction System Components Air Dryer Parts Figure 1.6 Air Dryer Base: The aluminum casting to which all air dryer components are assembled. Base contains threaded mounting holes. Refer to Figure a Figure 1.7 Desiccant Cartridge: A cylindrical steel housing that contains the filter element and desiccant necessary to filter and dry the air that passes through it. For easy maintenance, all Meritor WABCO air dryer cartridges are of spin-on/spin-off design. Refer to Figure a Figure 1.8 Heater Assembly: Located in the air dryer base, the heater keeps the water that collects in the air dryer from freezing. The assembly consists of a cylindrical resistive-type heating element and a small circular thermostat. The thermostat turns the heater on at 45 F (7 C) and turns it off at 86 F (30 C). Refer to Figure a Figure 1.9 Orifice and Check Valve Assembly: Controls the flow of air for regeneration. There are three sizes: 0.8 mm for systems with compressor ratings less than 21 CFM, 1.0 mm for compressor ratings between 21 and 35 CFM, and 1.3 mm for compressor ratings greater than 35 CFM. Refer to Figure a Revised Page 3

8 Section 1 Introduction Air Dryer Parts, Continued Figure 1.10 Charging Valve: Keeps control valves from shuttling while the system is filling and pressure is too low to ensure proper operation. Refer to Figure a Figure 1.11 Outlet Check Valve: Prevents air from flowing back through the air dryer and escaping out the purge valve during the compressor unload cycle, or while the vehicle is shut off. It is located in the outlet port of the air dryer. Refer to Figure a Figure 1.12 Purge Valve: Allows collected moisture and contaminants to be expelled from the air dryer during the unloaded cycle. The purge valve remains open for the entire compressor unload cycle. Refer to Figure NOTE: While the compressor is running, a mild flow of air will vent to atmosphere through the purge valve. This is a normal condition a Figure 1.13 Solenoid and Armature Assembly: Controls timing and operation of right and left piston assemblies. This determines which cartridge dries and which one regenerates. Refer to Figure a Page 4 Revised 11-02

9 Section 1 Introduction Air Dryer Parts, Continued Figure 1.14 Pressure Relief Valve: Protects the dryer from over-pressurization. May be installed using a street-t fitting, shown in Figure 1.14, or directly into the dryer casting on dryers with the appropriate port (Port 31). Refer to Figure a Figure 1.15 Piston Assemblies (Left and Right): Control air-flow direction between TWIN cartridges. Both piston assemblies have their own covers. Refer to Figure Left Piston Kit 2 Left Piston Cover Kit 3 Right Piston Kit 4 Right Piston Cover Kit Figure 1.16 Purge Silencer: Optional equipment. Used to reduce the noise level of dryer purge. Refer to Figure a Wiring Harness Options Two types of power harnesses are used with the TWIN; the Standard Wiring Harness and the E-Type Wiring Harness. The wiring harness is included with the original installation. For part numbers and other ordering information, refer to PB-96135, the TWIN parts book. Standard Wiring Harness Figure 1.17 The TWIN uses a standard two-circuit power harness for heater and timer/solenoid in most applications (standard compressors). Refer to Figure a Revised Page 5

10 Section 1 Introduction Wiring Harness Options, Continued Wiring/Plumbing Kit for E-Type Compressor Figure b A three-circuit power harness must be used with Holset E-Type compressors. An Econ valve and check valve assembly, as well as a special solenoid valve, are also required. Refer to Figure Three-circuit power harness 2. Econ valve 3. Solenoid valve 4. Check valve assembly An exploded view of the TWIN air dryer components appears in Figure Figure Left Piston Kit 2 Orifice Kit 3 Desiccant Cartridge 4 AIR DRYER BASE 5 Right Piston Kit 6 Right Piston Cover Kit 7 Solenoid & Armature Parts (3 Kits) 8 Charging Valve Kit b 9 Purge Valve Kit 10 Outlet Check Valve Kit 11 Heater Kit 12 Left Piston Cover Kit 13 Manufacturing Location Code 14 Part Number 15 Date Code First 2 Digits = Build Week/Last 2 Digits = Build Year Page 6 Revised 11-02

11 Section 2Troubleshooting and Testing Routine Maintenance Section 2 Troubleshooting and Testing To keep your Meritor WABCO System Saver TWIN operating efficiently, the following routine maintenance is recommended: Interval Weekly. Weekly, or as recommended by the vehicle OEM, whichever is most frequent. Every 2-3 years or more often depending on usage, vocation and condition of compressor. Whenever compressor is rebuilt. Required Action Check the exhaust from the air dryer. Check for moisture in the system by draining the supply tank. Replace the desiccant cartridge with new cartridges. Troubleshooting the TWIN Air Dryer System WARNING To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service. Engage the parking brake to prevent the vehicle from moving before you begin maintenance or service procedures that require you to be under the vehicle. Serious personal injury can result. Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Serious personal injury can result. Remove all air from the air system before servicing any component in the air system. Pressurized air can cause serious personal injury. Pressure Relief Valve Check the build date on the part identification tag to determine whether or not it has an integral pressure relief valve. Refer to Figure 2.1. If the build date is 11/96, or higher, it has an integral pressure relief valve which can be seen at the back of the dryer. Refer to Figure 2.2. Dryers without integral relief valves must use a pressure relief valve and street Tee fitting. Figure 2.1 Figure b a 1 ID Tag 2 Pressure Relief Valve Assembly 1 Pressure Relief Valve Revised Page 7

12 Section 2 Troubleshooting and Testing Meritor WABCO TWIN Air Dryer Troubleshooting Guide Condition Possible Cause Suggested Repair Air dryer does not work properly. Air dryer mounted too close to heat source, such as engine exhaust stack or muffler. Air delivered to air dryer exceeds 175 F (79 C). Lines blocked with dirt. Loose fittings. Air dryer not switching every 50 to 60 seconds during compressor loaded cycle. Verify proper installation. Extend length of compressor discharge line as required, or install cooling coil. Clear or replace lines. Tighten or seal fittings. Verify solenoid operating properly. Water in air system Desiccant saturated. Check timer (solenoid) and make necessary repairs. NOTE: If timer is working properly but dryer does not switch, check for sludge on valves. Clean the dryer. If condition is not corrected: Check pistons and make necessary repairs. Replace desiccant cartridge(s). Dryer leaks heavily from purge valve every other 60-second timer cycle. Dryer frozen (water in air dryer is freezing). Excessive amount of oil released from exhaust of air dryer. or Sludge build-up on air dryer base. Improper air pressure maintained at dryer; psi allows partial switching but does not seal valves for a second cycle. Problem with heater assembly. Power supply to heater interrupted or short-circuited. Low voltage to heater unit. Wrong voltage air dryer used (e.g., 24-volt in 12-volt system). Problem with air compressor. Worn turbocharger oil seals (turbocharged compressors only.) Install back-pressure control valve in system between outlet of dryer and source of air take-off. Replace heater assembly. Repair or replace power supply circuit. Replace fuse if needed. Ensure voltage is at least 10.5 volts (12-volt system) or 20 volts (24-volt system). Replace with proper air dryer. Repair or replace compressor. Replace desiccant cartridge(s). Repair or replace turbocharger. Page 8 Revised 11-02

13 Section 2 Troubleshooting and Testing Condition Possible Cause Suggested Repair Dryer does not purge when compressor unloads. Air pressure does not build in brake system. Air continues to flow from purge valve after air compressor unloads. NOTE: This could be accompanied by a loss of engine power. Internal valves not switching. Wrong air line or no air line connected to dryer Port 4. Control line from governor unloader port to air dryer leaking. Purge valve stuck closed. Problem with governor. Cutout pressure never reached by air compressor. Leak in air system. Problem with compressor. Air dryer control port (Port 4) plumbed wrong. Obstruction in air compressor discharge line or air dryer outlet line. Air compressor discharge line plumbed to air dryer outlet port (Port 2). CTI Applications: Back-pressure control valve installed incorrectly. Faulty compressor discharge hose. Compressor intake is turbocharged and there is no turbo cutoff valve in system. Orifice blocked, internal passages blocked, valve components covered with sludge. O-rings in bad condition (cut, worn). Connect air lines properly. Repair any leaks. Replace purge valve. Repair or replace governor. Check air system for leaks. If condition is not corrected: Check/repair compressor. Tighten all air line connections, test system for leaks, make necessary repairs. Repair or replace the compressor. Repair or replace problem air system components. Verify proper installation. Check lines for crimps or blockages. Make necessary repairs. Verify proper installation. Make necessary repairs. Verify installation of back-pressure control valve. Check for pinhole leaks along length of compressor discharge line from compressor to air dryer. If found, replace hose. Make sure replacement hose is capable of sustained high temperature use. Install a turbo cutoff valve. Clean as needed, replace worn parts. Make sure O-rings are properly installed and in good condition. Revised Page 9

14 Section 2 Troubleshooting and Testing System Tests Heater Resistance Figure 2.3 Solenoid Check Turn ignition on. Do not start engine. To ensure power to solenoid, check at cable with volt-ohmmeter, or test light. Refer to Figure 2.4. Go to TWIN dryer and listen for the solenoid to click. There should be one click every seconds. If not, solenoid is defective. Figure Heater 2 3 To avoid damaging components, Meritor WABCO recommends performing this resistance check with the heater in place. 1. Set volt-ohmmeter to ohms. 2. With wires connected and properly secured, attach one probe to the heater connector and the second to the lead on the thermostat. Refer to Figure Measure the resistance. 12-volt system: If ohms, resistance is acceptable. If the resistance is less than 1.0 ohm or more than 2.0 ohms, replace heater. 24-volt system: If ohms, resistance is acceptable. If the resistance is less than 5.0 ohms or more than 7.0 ohms, replace heater. 4. Reinstall components and vehicle harness. Leak Test 1. Drain the air from all system tanks. 2. Close the draincocks on all reservoirs. 3. Start the vehicle. Allow the air system pressure to build while the engine idles. 4. There will be a light airflow from the purge valve. This is normal and will continue until the air compressor unloads. After seconds, and if the system pressure has built to at least 60 psi, there will be a mild purge, or exhaust of air, as the dryer switches cartridges. If there is no purge, the solenoid may be bad. Refer to Solenoid Check box for a quick solenoid test. When the air system reaches cutout pressure, the dryer will purge completely. After purging, the dryer will not exhaust any air until the compressor starts up again. 1 Standard Harness P/N R Ground ( ) 3 Locating Pin 4 Positive (+) 5 Timer/Solenoid 6 Heater 5. Shut off the engine. 6. Apply a soap solution to each connection that contains pressurized air. Check the connections to see if soap solution bubbles. No soap bubbles Soap bubbles appear. 1 Connections are sealed properly. Connections not sealed properly. To repair: 1. Drain all reservoirs. 2. Remove leaking connection. 3. Inspect the connectors and ports for damaged threads or cracks. Replace if necessary. 4. Apply pipe sealant or Teflon tape to connection. Repeat leak test until all connections are sealed a Page 10 Revised 11-02

15 Section 3 Installing Replacement Parts Section 3Installing Replacement Parts WARNING To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service. Remove all pressure from the air system before you disconnect any component including the desiccant cartridge. Pressurized air can cause serious personal injury. Park the vehicle on a level surface. Block the wheels to prevent the vehicle from moving. Serious personal injury can result. A Component Replacement Guide appears on the inside back cover. Desiccant Cartridge NOTE: You may replace one or both TWIN cartridges. Figure Replacement kit contains one cartridge and one O-ring. Refer to Figure Loosen and remove the old cartridge. Use strap wrench if necessary. 3. Remove and discard O-ring from dryer base a Figure a 4. Inspect and clean seal seats. Repair any damage. NOTE: If seats are damaged so badly that a tight seal cannot be maintained, replace the air dryer. 5. Lubricate and install new O-ring on stem. 6. Thread replacement cartridge onto the base until the seal touches the base. Then, tighten the cartridge one-half (½) additional turn. Do Not Overtighten. Refer to Figure O-Ring 2 Seal Seat 3 Seal Revised Page 11

16 Section 3 Installing Replacement Parts Left Piston Cover Figure Remove 2 Install in-lbs ( N m) O-rings not included in cover replacement kit. T a 1. Remove the old cover. Use a 5 mm Allen wrench to loosen the mounting bolts. Remove bolts. Lift cover off of dryer. Refer to Figure 3.3. NOTE: If you are replacing the left piston assembly, refer to the following instructions. 2. If you are replacing the cover only: The two small O-rings that fit in the air passages and the two large O-rings that fit in the grooves in the outer diameter of the cover guide are not included in the cover replacement kit. Remove these O-rings from the old cover, clean, apply Meritor WABCO-recommended lubricant, and install them in the new cover. 3. Install the replacement cover. T ighten bolts to inch-pounds ( N m). T Left Piston Assembly Figure a These O-rings are installed in the cover, but are included with the piston assembly replacement kit. They should be replaced whenever you replace the piston assembly. 1. Review Figure 3.4 to make sure you have all of the parts required to replace the left piston assembly. Use the grease included with the replacement kit to lubricate O-rings and seals. 2. Remove the left piston cover (refer to instructions, above). Remove the two small O-rings from the breather holes and the two large O-rings from the grooves in the outer diameter of the cover guide. Clean the cover. Save cover and mounting bolts for reassembly. Seals, O-rings and springs are included in a separate replacement kit from the hard parts (piston, spool and lip seal). Refer to PB-96135, the TWIN Parts Book. Page 12 Revised 11-02

17 Left Piston Assembly, Continued Figure 3.5 Section 3 Installing Replacement Parts 3. Remove the left piston and spring assembly from the piston bore. Inspect and clean the bore area. Refer to Figure a Figure a 4. Lubricate and install the large replacement O-ring in groove on head of piston guide. Refer to Figure 3.6. Figure 3.7 Lip of seal must face away from dryer. Figure a a 5. If O-rings and spool are already installed on the piston, lubricate the rubber parts, then go to Step 6. If not: a. Install lubricated O-ring in first groove of piston guide. b. Use snap ring pliers to install snap ring in snap ring groove on shaft of piston. c. Install lubricated lip seal in groove of spool. Insert spool with lip seal onto piston. Lip of seal must face away from the dryer. d. Install lubricated O-ring in groove on piston shaft. e. Use snap ring pliers to install snap ring in snap ring groove under spool. f. Install lubricated O-ring in groove on piston shaft. Refer to Figure Install the two large, lubricated O-rings in the grooves in the outer diameter of the cover guide. Install the small lubricated O-ring in the breather hole on the cover. Refer to Figure Install spring in left piston cover. Insert piston assembly into left piston cover. Stem of piston will face away from dryer. Refer to Figure Replace the left piston cover. (Refer to instructions under Left Piston Cover. ) Revised Page 13

18 Section 3 Installing Replacement Parts Right Piston Cover Figure 3.9 The right piston cover replacement kit contains only the cover. When you remove the old cover, retain the mounting bolts for reassembly. Also, remove and save the two small, air passage O-rings. Refer to Figure 3.9. The right piston cover houses the solenoid/ armature and charging valve assemblies. Carefully remove and save these assemblies. Clean and inspect them before reinstalling in the new cover. You must also remove the right piston assembly when replacing the cover. If you are replacing any of these assemblies, you should follow the instructions that appear in this manual: Right Piston Assembly, (in this section) Charging Valve Assembly, (in this section) Solenoid and Armature Assembly, (in this section) Figure Unscrew the power harness and disconnect it from the solenoid. Remove and save the solenoid. Refer to Figure Carefully remove the armature assembly end cap and O-ring from the solenoid. Save these for reassembly. 3. Use a 5 mm Allen wrench to loosen and remove the three long piston cover bolts from the armature plate. Remove the armature assembly. Lift the cover off of the dryer. Save parts for reassembly. 4. Loosen and remove the short piston cover bolt. Save bolt for reassembly. 5. Remove the right piston cover. Remove and save the two small O-rings from the cover breather holes. Page 14 Revised 11-02

19 Right Piston Cover, Continued Section 3 Installing Replacement Parts Figure Loosen and remove the charging valve nut remove carefully, this is a spring-loaded valve. Remove the charging valve assembly from the right piston cover. Refer to Figure Carefully remove the right piston assembly from the dryer cavity. This will help avoid damage to the assembly when the new cover is installed. 8. Clean and lubricate the two small O-rings removed from the old cover. Install them in the breather holes in the replacement cover. 9. Replace the charging valve assembly in the right piston cover. Figure Insert the piston assembly into the piston cover cavity. Do not damage the lip seal during this procedure. Use the flat side of a small, flat screwdriver to tuck the assembly into the cover. Refer to Figure Install the cover, charging valve down, over the piston assembly. 12. Replace the short mounting bolt. Finger tighten only. 13. Replace solenoid and armature assembly. Refer to Solenoid and Armature Assembly in this section. 14. Connect the power harness to the solenoid. Make sure connection is tight. 15. Test the installation. Revised Page 15

20 Section 3 Installing Replacement Parts Right Piston Assembly Figure a 1. Review Figure 3.13 to make sure you have all of the parts required to replace the right piston assembly. Use the grease provided with the replacement kit to lubricate O-rings. 1 These O-rings are installed in the cover, but are included with the piston assembly replacement kit. They should be replaced whenever you replace the piston assembly. Seals, O-rings and springs are a separate replacement kit from hard parts (piston, spool and lip seal). Refer to PB-96135, TWIN Parts Book, for additional information. NOTE: You do not have to remove the charging valve when replacing only the right piston assembly. 1. Disconnect the power harness. Remove the solenoid and armature assembly. Remove the right piston cover. 2. Remove right piston assembly. Clean piston bore thoroughly. 3. Install large lubricated O-ring in groove on head of piston. 4. If O-rings and spool are already installed on the replacement piston, lubricate the rubber parts. Then, go to Step 5. If not: a. Use snap ring pliers to install a snap ring into snap ring groove closest to piston head. b. Insert lubricated lip seal in groove of spool. c. Install lubricated O-ring in groove on piston shaft. d. Install spring over piston shaft. e. Install spool with lip seal into piston shaft. Lip of seal will face away from air dryer. f. Install snap ring in groove on piston shaft to hold spool in place. g. Install O-ring into groove on piston shaft. 5. Insert piston and spring assembly into the right piston cover. Remove the two small O-rings from the piston cover. Lubricate the two new O-rings included in the right piston assembly replacement kit and install them in the piston cover. 6. Replace the right piston cover, armature and spring assembly, and solenoid. For detailed instructions: Right Piston Cover, (in this section) Solenoid and Armature Assembly, (in this section) Page 16 Revised 11-02

21 Section 3 Installing Replacement Parts Charging Valve Assembly Figure a NOTE: You do not have to remove the right piston cover or solenoid when replacing the charging valve assembly. 1. Check Figure 3.14 to make sure you have all of the parts needed to replace the charging valve assembly. Use the grease provided with the replacement kit to lubricate the O-ring and spring. Figure a 2. Remove dust cap from charging valve nut. Then, loosen and remove the nut remove nut carefully, this is a spring-loaded valve. Remove the old charging valve from the right piston cover. Refer to Figure Clean the charging valve bore and seat. Use the grease included with the replacement kit to lube the area. Figure a 4. Install piston and spring in cover bore. Refer to Figure Install lubricated O-ring in bore groove of special nut. 6. Install washer on nut. Insert nut into cover bore. Carefully guide piston into the bore in the nut. Figure Install lubricated rubber dust plug at end of nut. Refer to Figure a Revised Page 17

22 Section 3 Installing Replacement Parts Solenoid and Armature Assembly This assembly requires two replacement kits: Solenoid and Mounting Sleeve and Other Solenoid Parts. You will need both kits to complete the installation. (Refer to PB-96135, the TWIN parts book.) CAUTION To avoid damaging the solenoid, make sure you install the proper solenoid, 12-volt or 24-volt. Solenoid voltage is determined by the vehicle's electrical system. NOTE: Solenoid and Armature Assembly is installed on the right piston cover. Figure (2 Kits) Figure a 1. Check Figure 3.18 to make sure you have all of the parts needed to replace the solenoid and armature assembly. Use the grease included in the replacement kit to lubricate all O-rings. 2. Remove the old solenoid and armature assembly: a. Disconnect power harness. b. Lift solenoid off of cover. Refer to Figure c. Remove the three piston cover mounting bolts that hold the solenoid mounting plate in place. Retain bolts for use in reassembly. d. Remove breather from end of nut. e. Unscrew nut and remove from solenoid. f. Remove the O-rings, one from each side, from the solenoid. g. Remove the armature retaining plate. h. Remove Armature and Spring assembly a 1 Insert O-Ring Figure Inspect and clean the solenoid bore. Do not lube this area apply lube to O-rings only. 4. Install lubricated O-ring in groove on solenoid sleeve. 5. Insert the open end of the sleeve through hole in retaining plate. Refer to Figure Insert sleeve with armature and spring into cavity a Page 18 Revised 11-02

23 Solenoid and Armature Assembly, Continued Section 3 Installing Replacement Parts 7. Position armature retainer plate on cover, lining up holes on plate with holes in the cover. 8. Install the three long bolts through the armature retainer plate. T ighten all four bolts to in-lbs ( N m). T Figure Install lubricated O-ring on sleeve and position against mounting plate. 10. Position solenoid over sleeve, writing side facing dryer. Install lubricated O-ring in bore on dryer side of solenoid. Refer to Figure Install lubricated O-ring over end of sleeve. 12. Install nut at end of sleeve. Screw breather onto nut. Finger tighten. 13. Connect the power harness to the solenoid. Follow these steps to test solenoid. Turn ignition on. Ensure power to solenoid. Listen for click to sound after seconds. Click occurs: Solenoid O.K. No click: Voltage not sufficient or solenoid damaged or improperly installed. Heater Assembly NOTE: Select 12- or 24-volt replacement kit, depending upon vehicle voltage. Figure Check Figure 3.22 to make sure you have all of the parts needed to replace the heater assembly. 2. Disconnect the power harness. 3. Remove the two screws holding wiring connector in place a Figure Remove wiring harness and O-ring to access retainer screw. Refer to Figure Remove retainer screw. 6. Remove thermostat retainer a Revised Page 19

24 Section 3 Installing Replacement Parts Heater Assembly, Continued Figure Remove and discard the old heater assembly. 8. Inspect and clean the heater cavity. Area must be free of dust and oil. 9. If not assembled, attach power leads to thermostat and wiring connector. Insert the heater and thermostat with power leads into the heater cavity. Refer to Figure Figure Install the retainer and tighten the screw that holds the element and thermostat in place. 11. Install lubricated O-ring in base of wire connector. 12. Gently press wire connector into place in heater cavity. Tighten down the two mounting screws. Refer to Figure Connect heater assembly to power harness. 1 Mounting Screws Page 20 Revised 11-02

25 Section 3 Installing Replacement Parts Purge Valve Assembly Figure Review Figure 3.26 to make sure you have all of the parts required to replace the purge valve assembly. Use the grease included with the replacement kit to lubricate O-rings. NOTE: The shim may not be included with the kit. If it is not included, it is not required. If it is included, install it between the spring and valve body. 1 Shim Refer to Note a Figure Remove old purge valve assembly from bottom of air dryer. Refer to Figure Remove snap ring, valve body and spring. Pull valve assembly out of dryer base. Remove O-ring. 3. Inspect and clean valve bore. 4. Apply a thin layer of grease to the valve bore (use grease included in replacement kit). 5. Install lubricated O-rings: one in dryer base, one on valve head. 6. Install spring in valve head. 1 Spring 2 Valve Head 3 Valve Assembly 7. Insert valve body, wide end toward dryer, onto the piston shaft. NOTE: If a shim is included in the kit, install it between the spring and valve body. 8. Install the retainer ring. Revised Page 21

26 Section 3 Installing Replacement Parts Outlet Check Valve Assembly Figure a 1. Review Figure 3.28 to make sure you have all of the parts required to replace the outlet check valve assembly. Use grease provided with the replacement kit to lubricate O-rings and seals. Figure b 2. Remove the snap ring from dryer Port 2. Then, remove the old check valve assembly. Refer to Figure Inspect and clean valve bore. Remove any excess debris. Figure Install lubricated O-ring in groove on underside of check valve. Refer to Figure Install check valve in bore with shaft facing dryer a Figure Install perforated washer over top of spring. Refer to Figure While holding spring and washer in place, install snap ring in the bore groove a Page 22 Revised 11-02

27 Orifice Assembly Section 3 Installing Replacement Parts NOTE: Select 0.8 mm, 1.0 mm or 1.3 mm orifice replacement kit. Check the part number of the air dryer to determine orifice size. (Refer to PB-96135, the TWIN parts book.) Figure 3.32 Figure a 1. Review Figure 3.32 to make sure you have all of the parts required to replace the orifice assembly. Use the grease included with the replacement kit to lubricate O-rings and seals. 2. To access the orifice assembly, unscrew and remove the desiccant cartridge from the dryer base. Remove the O-ring. Save the cartridge and O-ring for reassembly. Refer to Desiccant Cartridge in this section for information about removing the desiccant cartridge. 3. Remove the old snap ring and orifice assembly from the base of the dryer. Refer to Figure Inspect and clean the orifice bore. 5. Install the perforated washer in dryer bore a Figure a 6. Install the spring on top of the perforated washer. Refer to Figure Install lubricated O-ring in groove on check valve stem. 8. Insert check valve into bore with the stem facing away from dryer. Revised Page 23

28 Orifice Assembly, Continued Section 3 Installing Replacement Parts 9. Install lubricated O-ring in groove on orifice part. 10. Install plastic orifice in bore. Carefully guide check valve into center hole. Refer to Figure NOTE: Molded ribs on orifice must face away from dryer. 11. Install snap ring to hold orifice assembly in place. Figure Install large lubricated O-ring over the dryer base where cartridge screws on. 13. Install the desiccant cartridge. Refer to Desiccant Cartridge in this section. Purge Silencer (Muffler) NOTE: This is an optional part designed to reduce dryer purge noise level. Figure Remove snap ring. Remove old silencer from purge valve head. Do not damage purge valve head. 2. Clean purge valve head. 3. Insert replacement silencer into purge valve head. Secure with snap ring. Refer to Figure Purge Valve Head 2 Silencer Page 24 Revised 11-02

29 Air Dryer Assembly Section 3 Installing Replacement Parts NOTE: This procedure is for removing and replacing a unit. For instructions on an initial installation, refer to TP-94104, Installing a System Saver TWIN Air Dryer. Figure a 1. Drain all pressure from the air system. Disconnect all air lines. Use markers to label the lines for proper reinstallation. Refer to Figure Disconnect the heater electrical plug from the heater receptacle and the solenoid connector from the solenoid/timer. 1 Drain air pressure and disconnect these air lines before replacing the dryer. Figure Remove the air dryer mounting bolts. Remove the air dryer from its mounting bracket. Refer to Figure Attach the new unit to the frame or mounting bracket with new mounting capscrews and washers. Tighten the capscrews to lb-ft (30 40 N m). Refer to Figure T a Figure Connect heater electrical plug to heater receptacle. Connect solenoid cable to solenoid/timer. 6. Reconnect all system air lines. 7. Test the installation b lb-ft (30-40 N m) T Revised Page 25

30 Notes Page 26 Revised 11-02

31 Appendix I Glossary Appendix IGlossary Basic Air System/Air Dryer Terms Air Compressor Air Dryer Air Governor Compressor Load Cycle Compressor Unload Cycle Cut-in Pressure Cut-out Pressure Desiccant Drying Cycle Purge Purge Cycle Regeneration A device that pumps air to and builds air pressure in an air system. A device that cools, filters, and dries the air delivered by an air compressor. A device that controls the operation of the air compressor by constantly monitoring air pressure in the supply tank of the air system. The air governor initiates the compressor unload cycle when the cutout pressure is reached. It also controls the air dryer by sending an air signal at the beginning of the compressor unload cycle to the control port of the air dryer. This initiates the purge cycle. When the signal is stopped, the purge valve closes and the drying cycle begins. The time during which the air compressor is building air pressure in an air system. The time during which the air compressor is idling and is not building air pressure in an air system. The pressure level in the air system supply tank that triggers the compressor load cycle. The pressure level in the air system supply tank that triggers the compressor unload cycle. A granular substance that has a high affinity for water. It catches and retains moisture from the air stream. The time during which the air dryer cools, filters and removes moisture from the air delivered by the air compressor. The initial blast of air (decompression) from the air dryer purge valve at the beginning of the compressor unload cycle. The time during which the air dryer is undergoing purge and regeneration. It begins at the start of the compressor unload cycle and normally ends well before the beginning of the compressor load cycle. The mild backflow of air through the non-loaded air dryer cartridge and out the purge valve. A small amount of air from one cartridge is used to remove moisture from the other cartridge. This readies the cartridge for the next cycle. The cycle lasts seconds, then the timer switches it to the other cartridge. Revised Page 1-A

32 Notes Page 2-A Revised 11-02

33 Appendix IIApplication Information General Requirements Appendix II Application Information Compressor discharge line should have a continual downhill turn to the air dryer. There should be no water traps (low points or kinks) in the line before or after the dryer. Mount air dryer so that there is no direct splash or spray from a wheel. Keep air dryer at least 12 inches from any heat-producing sources like exhaust manifolds or pipes, transmissions, etc. Make sure there are no valves or other devices in the dryer-to-supply-tank line to prohibit or restrict the flow of air back from the supply tank to the air dryer. The purge valve must be fed by a direct line from the air governor. For applications where the working pressure in the system could be lower than 85 psi (for example, bulk unloading or central tire inflation), install a back-pressure control valve. Operating Environment Requirements Figure 1-A Operating Parameter Requirement Temperature (ambient operating range) Electrical Power (for heater and solenoid/timer power) Thermostat Range (On/Off temp) 40 F to 175 F ( 40 C to 80 C) 12 or 24 volts available 45 F, 86 F (7 C, 30 C) Revised Page 3-A

34 Appendix II Application Information Operating Environment Requirements, Continued Figure 2-A GOVERNOR COMPRESSOR INTAKE LINE UNLOADER PORT RESERVOIR TO GOVERNOR LINE SYSTEM SAVER TWIN AIR DRYER COMPRESSOR DISCHARGE LINE COMPRESSOR CONTROL (PURGE) PORT DRYER INLET PORT DRYER OUTLET PORT CHECK VALVE SYSTEM RESERVOIR SYSTEM RESERVOIR TO BRAKE SYSTEM SUPPLY TANK CHECK VALVE d Discharge Line: Diameter from compressor to air dryer 1/2" i.d. minimum Length from compressor to air dryer Determined by temperature of air at the inlet port of the air dryer. At normal vehicle operating temperature, length must be sufficient to keep temperature below 175 F (80 C). Recommendations for minimum/maximum length: Under 21 cfm: 6 ft. min./20 ft. max. Use copper-pipe stainless-steel braided-teflon tubing for the first 10 feet (minimum). Any line over 10 feet should be insulated. Over 21 cfm: 10 ft. min./20 ft. max. Use copper-pipe stainless-steel braided-teflon tubing for the first 10 feet (minimum). Any line over 10 feet should be insulated. Rated Compressor size: Less than 21 cfm TWIN with 0.8 mm orifice Between 21 and 35 cfm TWIN with 1.0 mm orifice Greater than 35 cfm TWIN with 1.3 mm orifice cfm = cubic feet/minute Pressure Requirements: Maximum 140 psi Minimum 85 psi Flow Capacity: Compressor rating 50 cfm maximum Compressor On-Time (normal running): Unlimited Maximum Duty Cycle: 100% Page 4-A Revised 11-02

35 Installation Instructions for Special Applications Bulk-Unloading or Central Tire Inflation (CTI) Air Systems Appendix II Application Information Figure 3-A Bulk-unloading or CTI air systems require a back-pressure control valve. Refer to Figure 3-A. The back-pressure control valve maintains adequate pressure at the outlet of the dryer to ensure proper operation in high air usage applications. It is installed between the air dryer and the air distribution system, a minimum of five feet from the dryer. The arrow on the valve must point in the direction of the airflow. Refer to Figure 4-A. NOTE: These instructions are for adding a back-pressure control valve to an existing TWIN application. For new installations, refer to TP NOTE: Back-pressure control valve not required for Eaton CTI. 1 Arrow points in the direction of airflow. Installing a Back-Pressure Control Valve CAUTION The System Saver TWIN air dryer is designed and engineered to minimize moisture and contaminants in truck air brake systems. It is not designed to provide moisture-free or contaminant-free air in a bulk unloading application. The TWIN air dryer should not be used in bulk unloading applications if contaminants could cause load spoilage. The TWIN air dryer is not to be used in food-grade bulk unloading applications. WARNING To prevent serious eye injury, always wear safe eye protection when you perform vehicle maintenance or service. Block the wheels to prevent the vehicle from moving. Support the vehicle with safety stands. Do not work under a vehicle supported only by jacks. Jacks can slip and fall over. Serious personal injury can result. Remove all air from the air system before servicing any component in the air system. Pressurized air can cause serious personal injury. Revised Page 5-A

36 Appendix II Application Information Installing a Back-Pressure Control Valve, Continued Figure 4-A SYSTEM SAVER TWIN AIR DRYER UNLOADER PORT RESERVOIR TO GOVERNOR LINE TO BULK UNLOADER OR CTI DRYER OUTLET PORT COMPRESSOR DISCHARGE LINE CONTROL (PURGE) PORT DRYER INLET PORT C CHECK VALVE B SYSTEM RESERVOIR SYSTEM RESERVOIR TO BRAKE SYSTEM A SUPPLY TANK CHECK VALVE d Back-Pressure Control Valve (BPCV) NOTE: Locate the BPCV anywhere BETWEEN the air dryer and the air distribution system. Points A, B and C show several possible locations for the BPCV. If you select location C, air supply cannot be taken from Line B. Arrow on BPCV must point in direction of airflow. NOTE: The end user must provide bulk tank overpressure protection either in the system or on the trailer. 1. Drain all air from the system. 2. Determine where the back-pressure control valve will be installed. It must be at least 5 feet from the air dryer. Do not nipple mount the back-pressure control valve to the dryer. Refer to Figure 4-A for suggested mounting locations. 3. Find the directional arrow on the replacement valve. Install the valve so that the arrow points in the direction of airflow. Installation orientation is not important. It does not matter which end faces up or down. 4. Test the installation for leaks. For part number and order information, refer to PB If you need assistance determining the necessity of a back-pressure control valve in your application, contact Meritor Customer Service, Page 6-A Revised 11-02

37 Appendix II Application Information Holset E-Type Compressor Systems Function Meritor WABCO offers a special Holset E-Type wiring harness for systems using a Holset E-type compressor. This harness is shown in Figure In addition, an Econ valve, check valve and solenoid valve assembly are also required. Refer to Figure 5-A. E-type compressors can be identified by the serial number tag on the compressor. Tag will indicate: This is an E-Type compressor. For proper operation, the discharge line must be kept at reservoir pressure when the governor is in the unloaded position (compressor not pumping). If this is not done, the compressor will pass excessive oil into the air system. Figure 5-A A FROM AIR COMPRESSOR DISCHARGE LINE GOVERNOR COMPRESSOR INTAKE LINE UNLOADER PORT UNLOADER LINE RESERVOIR TO GOVERNOR LINE SYSTEM SAVER TWIN AIR DRYER FROM AIR GOVERNOR UNLOADER PORT FROM SUPPLY TANK TO AIR DRYER INLET PORT COMPRESSOR DRYER OUTLET PORT COMPRESSOR DISCHARGE LINE TEE FITTING CHECK VALVE DRYER INLET PORT CHECK VALVE SYSTEM RESERVOIR SYSTEM RESERVOIR TO BRAKE SYSTEM ECON VALVE (REFER TO INSET A) TO SUPPLY TANK SOLENOID VALVE (REFER TO INSET B) SUPPLY TANK CHECK VALVE b B TO ECON VALVE d NOTE: Normally-closed solenoid valve installed such that when ignition is on, solenoid is energized and solenoid valve is open, allowing air to flow from supply tank to compressor discharge line. Revised Page 7-A

38 Appendix II Application Information Econ Valve Econ Valve Operation The Econ valve allows supply tank pressure to reach the compressor discharge line during compressor idle. When the compressor is pumping, the Econ valve lets compressor air flow into the air dryer, then on to the supply tank. When cutout pressure is reached, the governor unloads the compressor, and pressurizes Port 4 of the dryer. This opens the purge valve in the dryer and expels moisture and contaminants. At the same time, the piston in the Econ valve shifts position and blocks the flow of air into the dryer. This also allows air to flow from the supply tank into the compressor discharge line. When the compressor starts pumping again, the cycle is repeated. A check valve at the supply tank prevents air from bypassing the dryer and going directly to the supply tank during the pumping cycle. Refer to Figure 5-A for an illustration of this system. Replacing the Econ and Check Valves on a Holset E-Type Compressor System NOTE: When the OEM installed the Holset E-type compressor system, a one-way check valve, Econ valve and solenoid valve were plumbed into the system between the air dryer and the supply tank. The Econ valve must be located two to seven feet from the compressor. 1. Remove air from the system tanks and disconnect the air lines from the Econ and check valves. To ensure proper replacement, use markers to identify the lines. Econ valve ports are identified below. Refer to Figure 6-A. Figure 6-A Econ Valve Ports Inlet Port (1/2"-14 NPTF, female) Outlet Port (1/2"-14 NPTF, male) Unloader Port (1/8" NPTF, marked UNL on valve) Make-up Air Port (1/8" NPTF) 2. Attach check valve to Econ valve or supply tank. 3. Reconnect the air lines. Test the system for leaks. Replacing the Solenoid Valve The solenoid valve can be mounted anywhere in the line between the Econ valve and the supply tank. Refer to Figure 5-A. 1. Remove air from all system tanks. Disconnect the air line from the solenoid valve. 2. Unplug the solenoid from the wiring harness. 3. Look at the existing installation and remember how the old solenoid valve is installed. The replacement valve will be installed the same way. 4. Remove the old solenoid valve. 5. Install the replacement solenoid valve exactly the way the old valve was installed: The normally-closed solenoid must be installed so that when the ignition is on, the solenoid is energized and the solenoid valve is open. 6. Reconnect the solenoid valve to the wiring harness. Insert plug until latch snaps over tab on the mating connector. 7. Test the system for leaks. Page 8-A Revised 11-02

39 Appendix II Application Information Installing a Turbo Cutoff Valve If your vehicle has a turbocharged engine and the air compressor draws its intake air from the pressurized side of the turbocharger (at the intake manifold or aftercooler), you may want to install a turbo cutoff valve on your Meritor WABCO air dryer. This installation will prevent leakage of turbo boost through the air compressor and out of the purge valve of the air dryer when the compressor is operating in the unloaded mode. Contact Meritor Customer Service for part number information ( ). Installation Instructions Installing the T-Fitting 1. Remove the unloader line from port 4 on the air dryer. 2. Install a standard braking system T-fitting that has three 1/8-inch NPTF ports on the unloader line. 3. Connect a line from the T-fitting to port 4 on the air dryer. Use 1/4-inch (6.3-mm) standard braking-system nylon tubing. 4. Connect a line from the remaining port on the T-fitting to the 1/8-inch MPT port marked UNL on the turbo cutoff valve. Use 1/4-inch (6.3-mm) standard braking-system nylon tubing. CAUTION Make sure there are no kinks or sags in the lines connected to the turbo cutoff valve. Moisture and dirt can build up and block the lines. The turbo cutoff valve and the air dryer will not work when these lines are blocked. 1. Park the vehicle on a level surface. 2. Stop the engine. 3. Drain pressurized air from all reservoirs to 0 psi (0 bar). 4. Disconnect the delivery line at port 1 on the air dryer. NOTE: If there is not enough room to install the turbo cutoff valve to port 1 on the air dryer, connect a 90 fitting to port 1 of the air dryer. Then connect the threaded end of the turbo cutoff valve to the fitting. 5. Install the threaded end of the turbo cutoff to port 1 on the air dryer. Make sure the arrow on the turbo cutoff valve points toward port Connect the delivery line from the compressor to the 1/2-14 NPT port marked with an arrow ( ) on the turbo cutoff valve. Revised Page 9-A

40 Appendix II Application Information Figure 7-A A FROM AIR COMPRESSOR DISCHARGE LINE GOVERNOR COMPRESSOR INTAKE LINE RESERVOIR TO GOVERNOR LINE FROM AIR GOVERNOR UNLOADER PORT TO AIR DRYER INLET PORT UNLOADER PORT UNLOADER LINE SYSTEM SAVER TWIN AIR DRYER PLUG COMPRESSOR DRYER OUTLET PORT COMPRESSOR DISCHARGE LINE TEE FITTING DRYER INLET PORT CHECK VALVE SYSTEM RESERVOIR SYSTEM RESERVOIR TO BRAKE SYSTEM TURBO CUTOFF VALVE (PLUMB ECON VALVE PER INSET A) SUPPLY TANK CHECK VALVE d Testing the Turbo Cutoff Valve 1. Close the drain cocks on all reservoirs. 2. Start the vehicle. Wait for the braking system to pressurize. 3. If you hear the air dryer exhaust air after the compressor cuts out, the air dryer is working correctly. You can also use the following test: 1. Apply the brakes of the vehicle several times to reduce pressure in the air system below the cut-in pressure of the governor. 2. If the air dryer exhausts air after the compressor cuts out, the air dryer is working correctly. Final Checks 1. Start the vehicle. Wait for the air system of the vehicle to reach maximum normal pressure. 2. Apply a soap solution to each connection that contains pressurized air. a. If soap bubbles do not appear, you correctly sealed the connections. b. If soap bubbles appear: Turn off the ignition. Depressurize all air tanks. Remove the leaking connection. Apply pipe sealant to the connection. Repeat Steps 1 and 2. Page 10-A Revised 11-02

41 TP REPLACEMENT CARTRIDGE PART NO. R Vehicle Air System E This layout is similar to the Cummins System E air system arrangement. Application Appendix II Application Information Used with high volume air compressors (Meritor WABCO, Holset, Bendix, Knorr, etc.). This air system arrangement may also be found on vehicles with other engine makes. Figure 8-A ENGINE AIR FILTER ENGINE TURBO HIGH VOLUME AIR COMPRESSOR OPTIONAL TURBO INLET Min 1/4 I.D. gov line (down to condenser tank) GOV Set compressor governor to 130 psi cutout. 15 FT (7/8" I.D.) TEFLON WIRE BRAID TUBING 2500 CU IN RECEIVER TANK HEATED SPITTER 175 PSI OUT IN SAFETY VALVE WABCO SS TWIN EXH 12 (5/8" I.D.) LINE 3-WAY NORMALLY OPEN SOLENOID VALVE WIRED TO IGNITION CIRCUIT SYSTEM STEM SAVER TWIN Ensure dryer has 1 mm orifices in regen circuit. SUPPLY TANK SPITTER 18 SCFM MAX ACCESSORY PORT CHECK VALVE PRIMARY TANK CHECK VALVE SECONDARY TANK BRAKE SYSTEM 2 SCFM Normal usage for brake system Maximum air supply volume is 8000 cubic inches (3 tanks) a Revised Page 11-A

42 Notes Page 12-A Revised 11-02

43

44 Meritor WABCO Vehicle Control Systems 3331 West Big Beaver Road, Suite 300 Troy, MI USA meritorwabco.com Information contained in this publication was in effect at the time the publication was approved for printing and is subject to change without notice or liability. Meritor WABCO reserves the right to revise the information presented or discontinue the production of parts described at any time. Copyright 2002 Maintenance Manual 35 ArvinMeritor, Inc. Revised All Rights Reserved Printed in the USA 16579/24240