Air Processing Unit ZB44..

Systems for Commercial Vehicles Service Manual Air Processing Unit ZB44..

Disclaimer The information contained herein is intended for the exclusive use of trained persons within the commercial vehicle industry, and must not be passed on to any third party. All recommendations regarding products and their servicing or usage are with reference to products and should not be considered applicable to products from other manufacturers. This information does not purport to be all-inclusive and no responsibility is assumed as a result of its use. We cannot accept any liability nor offer any guarantee regarding data accuracy, completeness or timeliness. The information does not represent any guarantee or ensured characteristics of the Products or Systems described. No liability can be accepted based on the information, its use, recommendations or advice provided. In no event may we be held liable for any damage or loss except in the case of wilful intent or gross negligence on our part, or if any mandatory legal provisions apply. This disclaimer is an English translation of a German text, which should be referred to for all legal purposes. Any legal disputes arising from the use of this information shall be subject to German law.

Contents Safety and Environment Guidelines. 4. Introduction. 5. Service Intervals. 5.2 Basic Principles..................... 6 2. Components. 9 Serviceable Components of the Air Processing Unit............ 9.. 3. 0 3. Removal and Replacement of the Desiccant Cartridge (A). 0 3.2 Removal and Replacement of the Heater Assembly (B). 3.3 Removal and Replacement of the Silencer Assembly (C)........ 2 3.4 Removal of the Air Processing Unit from the Vehicle......... 3 3.5 Removal and Replacement or Service of the Oil Separator Unit (D)..... 4 3.6 Disassembling and Assembling the Purge Valve (E).......... 7 3.7 Disassembling and Assembling the Tyre Inflator (F).......... 9 3.8 Replacement of the Double Pressure Sensor (H).......... 20 3.9 Removal and Replacement of the Time Switch Piston (I)........ 2 3.0 Refitting the Air Processing Unit to the Vehicle.......... 23 3

Safety and Environment Guidelines Note: The safety advice listed below is applicable to general service and diagnostic work on braking systems. Also observe any recommendations from the axle or vehicle manufacturer concerning towing, jacking-up and securing the vehicle. Before and during working on or around compressed air systems and devices, the following precautions should be observed: Always wear safety glasses when working with air pressure. 2 Never exceed the vehicle manufacturer s recommended air pressures. 3 Never look into air jets or direct them at anyone. 4 Never connect or disconnect a hose or line containing pressure; it may whip as air escapes. 5 When removing or servicing a product, ensure all pressure related to the specific system it is contained in has been depleted to 0 bar. Be aware that if the vehicle is equipped with an air dryer system, it can also contain air pressure along with its purge reservoir, if fitted, even after pressure has been drained from the other reservoirs. 6 If it is necessary to drain the air pressure from reservoirs, etc., keep away from brake actuator push rods and levers since they may move as system pressure drops. On vehicles fitted with air suspension, it is advised when undertaking such work, to support the chassis from sudden lowering and therefore prevent any possibility of being trapped between the chassis and axle or ground. 7 Park the vehicle on a level surface, apply the parking brakes, and always chock the wheels as depleting vehicle air system pressure may cause the vehicle to roll. 8 When working under or around the vehicle, and particularly when working in the engine compartment, the engine should be shut off and the ignition key removed. Where circumstances require that the engine be running, EXTREME CAUTION should be taken to prevent personal injury resulting from contact with moving, rotating, leaking, heated or electrically charged components. Additionally, it is advisable to place a clear sign on or near the steering wheel advising that there is work in progress on the vehicle. 9 Examine all pipework for signs of kinks, dents, abrasion, drying out or overheating. Be aware that kinks in pipework may result in air pressure being trapped in the pipework and associated equipment. Replacement hardware, tubing, hose, fittings, etc. must be of equivalent size, type and strength as original equipment and be designed specifically for such applications and systems. Check the attachment of all pipework; it should be installed so that it cannot abrade or be subjected to excessive heat. 0 Components with stripped threads or damaged/corroded parts must be replaced completely. Do not attempt repairs requiring machining or welding unless specifically stated and approved by the vehicle or component manufacturer. Never attempt to install, remove, disassemble or assemble a device until you have read and thoroughly understood the recommended procedures. Some units contain powerful springs and injury can result if not properly dismantled and reassembled. Use only the correct tools and observe all precautions pertaining to use of those tools. 2 Before removing any device note its position and the connections of all pipework so that the replacement/serviced device can be properly installed. Ensure that adequate support or assistance is provided for the removal/installation of heavy items. 3 Use only genuine replacement parts, components and kits as supplied by or the vehicle manufacturer. 4 The serviced or replaced product must be checked for correct function and effectiveness. 5 If products have been dismantled, serviced or replaced, whose performance could affect braking performance or system behaviour, this should be checked on a roller dynamometer. Bear in mind that a lower performance may be experienced during the bedding-in phase if new brake pads/ linings and/or brake discs/drums have been fitted. 6 Prior to returning the vehicle to service, make certain that all components and the complete brake systems are leak free and restored to their proper operating condition. Welding To avoid damage to electronic components when carrying out electrical welding, the following precautions should be observed: In all cases, before starting any electrical welding, remove all connections from any electronic control units or modules, noting their position and the order in which they are removed. 2 When re-inserting the electrical connectors (in reverse order) it is essential that they are fitted to their correct assigned position - if necessary this must be checked by PC Diagnostics. Disposal of Waste Equipment by Business Users in the European Union This symbol on the product, packaging or in user instructions, indicates that this product must not be disposed of with other general waste. Instead, it is your responsibility to dispose of the waste electrical and electronic parts of this product by handing them over to a company or organisation authorised for the recycling of waste electrical and electrical equipment. For more information about arrangements for waste equipment disposal please contact your distributor or local representative. 4

Introduction. Service Intervals The service interval is the length of time from the vehicle first entering service, or from the last service, until the point in time or distance travelled by the vehicle (whichever is the earlier) when it is recommended that the specified braking system device is serviced using a genuine service kit or replaced with a new part, or in the case of ABS subjected to a system functionality check. This service interval is provided for preventative maintenance purposes so as to minimize the probability of a vehicle breakdown. The service interval does not preclude the intermediate testing of the device on the vehicle to ensure that it is functioning in a correct manner, or the correct maintenance of other devices in the system that may influence the service interval. The service interval can be influenced by the application and the operating conditions of the vehicle. The following service intervals are based on the assumption that each device is positioned so it cannot be inadvertently abused or that external rubber boots/seals are not exposed to abnormal influences. In general, service kits contain all of the components that can deteriorate with use, such as rubber parts (O-rings, special seals, bonded inlet/exhaust valves, exhaust flaps), plastic and metal parts (filter elements and springs), fasteners and the correct grease. The range of kits is designed to enable each device to be serviced in part or completely. service kits are only designed for use with genuine devices and are only to be used in the manner detailed in these service instructions. After servicing, the device must also be checked in accordance with service instructions to ensure correct operation before the vehicle is placed back in service. Service interval Service Notes Refer to vehicle manufacturer. 30 000 km recommended. Refer to vehicle manufacturer. year recommended. Clean the oil separator and replace the O-Rings (If necessary the service interval can be revised, depending on the amount of oil carryover). Replace the desiccant cartridge. Replace the oil separator, if necessary. Failure of the air processing unit to purge or non-replacement of the desiccant cartridge at the recommended interval can cause a reduction in the service interval of downstream components. Additional checks In addition to the above, and any legally required periodic vehicle inspections, it is recommended that simple routine inspections of a general nature are carried out to maintain the braking system at a high level of functionality. These simple routine inspections should be () the weekly checking for excess water in the reservoirs by operation of the reservoir drain valves, and (2) the 6 monthly / (50,000 km) checking of the complete braking system for excessive air leakage during a maximum pressure foot brake application with the vehicle stationary and the parking brake released. 5

Introduction.2 Basic principles The ZB44.. range of air processing units combines the functions of a conventional air dryer with those of a pressure regulator and multi-circuit protection valve in one monoblock housing..2. Features Classic air drying functionality Multi-circuit protection valve functionality Integrated unloader function Integral safety function (air dryer) Exhaust safety function (Multi-circuit protection valve, EC) Two integrated pressure sensors (Optional) ESS Compressor control (Optional but recommended) Regeneration either via reservoir or by time switch High pressure tyre inflation with safety valve (Optional) System pressure tyre inflation (Optional) Air suspension supply (Optional) Heater (Optional) Oil separator (Optional) Silencer type (Optional).2.2 Functionality The air processing unit is fitted in the compressor discharge line of an air braking system to remove water, dirt, carbon and oil from the compressed air and therefore prevent it entering the vehicle air reservoirs during the Charge phase. It controls the system pressure (unloader function). It also maintains a pre-set pressure in the unaffected circuits of a multi circuit braking system in the event of a failure in one circuit (multi-circuit protection valve function). When the increasing air pressure in the braking system reaches a preset value (cut-out pressure), the unloader valve signals the purge valve to open and the air processing unit enters the Purge phase. This allows the trapped dirt and condensate to be expelled and the desiccant to be regenerated with clean, dry air from a separate purge reservoir or with air from the brake system using an integral timer. During this phase, air delivered by the compressor is discharged to atmosphere and does not enter the braking system. When, due to normal usage, the air pressure in the braking system drops, to the closing pressure of the unloader valve, it signals the purge valve to close and the Charge phase begins again..2.3 Air dryer element Drying function During the Charge phase, compressed air enters the air processing unit through port and passes through the oil separator element to remove particles and oil from the air using the cyclotron principle. This helps to maintain the quality of the desiccant bed, prolonging its life and effectiveness. It continues up the outside of the inner desiccant cartridge and then passes down through the desiccant bed to remove the water vapour. The now clean, dry air opens the delivery check valve, flows through the multi-circuit protection valve, and is delivered from ports 2, 22, 23 and 24 to charge the vehicle braking system. 6

Introduction Unloader function The pressure after the delivery check valve also flows to the unloader valve. When the increasing system pressure reaches the preset cut-out pressure, the unloader valve sends a pressure signal to the purge valve. Purge function The pressure from the unloader valve causes the purge valve to open which connects the initial drainage chamber to atmosphere through exhaust port 3 and the accumulated condensate. Oil and solid matter is then ejected. If the compressor control function is not used and the purge valve is open, air from the compressor discharges directly to atmosphere through the purge valve seat and exhaust port 3. Regeneration function The resulting drop in pressure in the initial drainage chamber causes air to flow back through the desiccant bed and allows the delivery check valve to close. At the same time clean, dry air flows back through the desiccant bed, collecting water from the desiccant and regenerating it ready for the next Charge phase. The wet air then flows down the outside of the inner desiccant cartridge and is discharged to atmosphere through the exhaust port 3. Subsequent operation of the braking system will cause the downstream air pressure to fall. When the pressure drops to the cut-in pressure, the pressure signal from the unloader valve to the purge valve drops to zero and the purge valve closes. The Charge phase will then begin again and the braking system pressure will build. For air processing units with time switch the compressed air required for regeneration is taken from the supply air reservoirs mounted downstream in the system. The regeneration time is determined by the pneumatic time switch and depends on the supply volume and the operating pressure of the pneumatic system. Air processing units without time switch require a separate reservoir for the regenerating air, the size of which depends on the system volume and the cut-out pressure. During the Charge phase the separate purge reservoir is charged through port 25. Timing function (optional) During the Charge phase, some of the clean dry air from the desiccant bed passes through the timing choke and charges the integral timing reservoir. During the Purge phase, the loss of pressure in the inlet cavity will close the delivery check valve. Some dry air from the brake service reservoirs is permitted to return through the multi-circuit protection valve then through the purge choke. This air flows back through the desiccant bed and the oil separator and collects water from the desiccant regenerating it ready for the next charge cycle. After a predetermined time, determined by the size of the timing choke, the air pressure in the timing reservoir will drop sufficiently for its piston to close and stop the return feed from the brake system. This stops the purge phase, but the compressor remains unloaded. The sizes of the timing choke and the purge choke are designed to match the system requirements such that the Purge phase is completed well within the compressor off-load cycle and sufficient air is returned to fully regenerate the desiccant..2.4 Multi-circuit protection element Basic function The multi-circuit protection valve consists of four individual pressure protection valves connected together in various configurations and each having limited feedback capability. Air is supplied through the delivery check valve in the air dryer element, and is delivered from ports 2-24 to circuits to 4 respectively. Circuits and 2 may have a bypass feature (optional). When the opening pressure of each valve element is reached, the diaphragm will lift, allowing air to flow past the valve seat into the respective delivery port and to circuits 23 and 24 from circuits 2 and 22 depending on the valve configuration. Due to air usage or leakage etc, when the falling pressure reaches the closing pressure, the diaphragm will drop and the supply-to-delivery path will close. Opening pressure The opening pressure is the pressure required to open a valve element when the respective downstream circuit is at zero pressure. If a circuit is not at zero pressure, the downstream pressure will also be acting on the diaphragm. This means that a lower pressure will be required to open the valve element, i.e. the actual opening pressure is dependent on the downstream pressure and is therefore usually lower than the stated value for the valve. 7

Introduction Static closing pressure The static closing pressure is the pressure at which the valve element will close in the event of slow air usage (e.g. leakage) from any circuit while the compressor is not charging. The closing pressure is determined by the area of the diaphragm and the preload of the graduating spring. It is always lower than the opening pressure. Dynamic closing pressure In the event of a rapid pressure drop in a circuit, the dynamic closing pressure will be maintained in the other circuits. It is always higher than the static closing pressure and is determined by the rate of air pressure loss in the circuit, the amount of air being recharged and by the reservoir volume of the individual circuits. Non-return valves The non-return valves retain pressure in circuits 23 and 24 in the event of a pressure drop in circuits 2 and 22. Exhaust safety function (EC function) The exhaust safety function of the multi-circuit protection valve ensures that once applied the spring brakes cannot be released unless there is at least sufficient pressure in the service brake system to achieve the prescribed residual service braking performance of the laden vehicle. Charging sequence Parallel charging This configuration is not designed to charge each circuit sequentially. In an initially empty air system there is no fixed opening sequence. This is particularly true if the system is already partly charged since the opening pressure of circuits 23 or 24 could be much lower than that for circuits 2 or 22. (See opening pressure section above). To ensure circuit 2 or 22 open first and in a reasonable time, circuits 2 and 22 have a bypass feature. Series charging This configuration is designed so that at least one of the circuits 2 and 22 will open before circuits 23 and 24. Between circuit 2/22 and 23/24 there are non-return valves. Circuits 2 and 22 may also have a bypass feature to speed up the filling of these circuits. Bypass The bypass feature is an air passage in each circuit 2 and 22 which connects the supply to the respective delivery ports (2 and 22) when their valve elements are closed. As a result, pressure can build in the unaffected circuits and they will charge normally. The connections have a small non-return valve to prevent loss of air in the reverse direction. 8

2 Components Serviceable Components of the Air Processing Unit Exploded View A D I H B F E C Part Identification and Service Kits For Service Kit Part Number see www.knorr-bremsecvs.com Item Description Comments / Variants A B C D E F H I Desiccant cartridge Heater assembly Silencer Oil separator Purge valve High pressure tyre inflator Double pressure sensor Time switch For standard applications For low temperature applications (-45 ºC) Heater 2 V 27x Heater 24 V 27x Heater 24 V Bayonet - ISO570 Oil separator complete Oil separator seals For standard applications For low temperature applications (-45 C) 9

3. Removal and Replacement of the Desiccant Cartridge (A) Part Identification Item Description Qty Desiccant cartridge 2 O-ring Note that component numbering may not correspond to that shown on separate Service Kit leaflets. 2 For Service Kit Part Number see www.knorr-bremsecvs.com Service Steps Step Service task Removal with the air processing unit still fitted to the vehicle Before starting work on the vehicle please refer to the safety and environment guidelines on page 4. 2 Clean the outside of the air processing unit and its surroundings to prevent entry of dirt. 3 Vent the air processing unit cartridge by charging the compressed air system until the cut-out pressure of the unloader valve has been reached and the air processing unit has subsequently purged. 4 Switch off the engine. To remove the air processing unit from the vehicle please refer to section Removal of the Air Processing Unit from the Vehicle. Removing the cartridge Unscrew desiccant cartridge () counter-clockwise, using suitable strap wrench. 2 Remove O-ring (2). 3 Wipe the body with a clean rag. Protect the clean air chamber and cartridge mounting thread from dirt. Fitting the cartridge Lightly lubricate the gasket at the base of the new cartridge () with grease. 2 Lubricate new O-ring (2) with grease. 3 Fit O-ring (2) over the cartridge retaining thread. 4 Screw desiccant cartridge () up to stop. 5 Fully tighten desiccant cartridge () by turning a further ½ turn using a suitable strap wrench. 6 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. 7 Charge the air system to just below cut-out pressure and check the new desiccant cartridge for leakage. 0

3.2 Removal and Replacement of the Heater Assembly (B) Part Identification Item Description Qty Heater assembly 2 Screw Note that component numbering may not correspond to that shown on separate Service Kit leaflets. For Service Kit Part Number see www.knorr-bremsecvs.com 2 M27x (2V & 24V) Bayonet - ISO570 Service Steps Step Service task Removal of the heater assembly Clean the outside of the air processing unit and the surroundings of the heater area. 2 Unscrew electrical connector locking ring and unplug connector (not shown). 3 Undo screw (2). 4 Remove heater assembly (). Replacement of the heater assembly Fit new heater assembly () into body. 2 Tighten new screw (2) to a torque of 3.5 Nm. 3 Refit the electrical connector and hand tighten the locking ring (not shown).

3.3 Removal and Replacement of the Silencer (C) Part Identification Item Description Qty Silencer assembly For Service Kit Part Number see www.knorr-bremsecvs.com Service Steps Step Service task Removal of the silencer assembly Remove silencer assembly () Replacement of the silencer assembly Locate new silencer assembly () over its spigot on the base of the air processing unit. 2 Lightly tap the silencer assembly () in the direction of the spigot so that it snaps into place. 3 Check the fixation of new silencer. Repeatedly charge and vent the air system between cut-out and cut-in pressure. Silencer must not be blown out by venting air. 2

3.4 Removal of the Air Processing Unit from the Vehicle Fig. Fig. 2 Service Steps Step Service task Before starting work on the vehicle please refer to the safety checks on page 4. 2 Vent the system air pressure completely. 3 Disconnect air lines after noting which port they are connected to for correct reinstallation. 4 Unscrew and remove the three M2 mountings (bolts, Fig. or nuts, see Fig. 2). 5 Remove the air processing unit and cover the ports to prevent entry of dirt. 3

3.5 Removal and Replacement or Service of the Oil Separator Unit (D) Part Identification and Service Kits 6 Item Kit Description Qty t Oil separator unit 2 t O-ring Ø 92 x 2.5 mm 3 t O-ring Ø 42 x 2.5 mm 4 t Screw M 4 x 40 mm 2 5 t O-ring Ø 33 x 5 mm 6 Desiccant cartridge t Oil Separator complete Oil Separator seals Note that component numbering may not correspond to that shown on separate Service Kit leaflets. 5 For Service Kit Part Number see www.knorr-bremsecvs.com 2 3 Fig. 4

Service Steps Removing the oil separator Step Service task Clean the outside of the air processing unit and its surroundings to prevent entry of dirt. 2 Secure the ZB44.. either to a simple fixture or using the mounting bolts/studs to make it stable. 3 Unscrew desiccant cartridge (6) counter-clockwise, using suitable strap wrench. 4 Remove the screws (4) and O-ring (5). 5 Fit a suitable pulling tool (7) into oil separator unit (Fig. 3). For detailed specification and correct fitting of recommended tool see page 6. 6 Pull out the oil separator unit () using pulling tool (7). If the oil separator unit () is not being replaced (depending on kit purchased), clean the the original unit () with 7 water using a high pressure hose or alternatively with gasoline. Also clean the housing using a soft cloth. Fitting the oil separator Step Service task Check that the sealing surfaces of the oil separator unit () and the cartridge neck (not shown) are clean. Fit the new O-rings (2 and 3) (Fig. on Page 5) and lightly grease them. 2 Put 2 rods (Ø 2.5 mm) (Fig. 4) into the threads for screws (4) to guide the oil separator into the body (Fig. 4). 3 Place the new oil separator unit () or cleaned original unit (dependent on kit purchased) into the body. Push the unit down until it is correctly seated. 4 Fit and tighten screws (4) to a torque of 2.5 Nm. 5 Lightly lubricate the gasket at the base of the cartridge (6) with grease. 6 Lubricate new O-ring (5) with grease. 7 Fit O-ring (5) over the cartridge retaining thread. 8 Screw desiccant cartridge (6) up to stop. 9 Fully tighten desiccant cartridge (6) by turning a further ½ turn using a suitable strap wrench. 0 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. Charge the air system to just below cut-out pressure and check the desiccant cartridge for leakage. 6 5 4 7 Fig. 2 Fig. 3 Fig. 4 5

Recommended pulling tool for Oil Separator Unit disassembly Holder with threaded bolt Adjustable pulling arms Thrust plate for threaded bolt Correct fitting of pulling tool Components of pulling tool Ø35 5 90º 3 6 max.3º 5º 0 min.50 90º 2.8 R 3 Ø20 Ø3 Dimensions of thrust plate 0-60 59 R3 6.5 Dimensions of pulling tool legs 5 6

3.6 Disassembling and Assembling the Purge Valve (E) 2 3 4 5 Part Identification Item Kit Description Qty Piston assembly 2 Compression spring 3 O-ring Ø 24 x.5 mm 4 Cover 5 Retaining ring included in kit Note that component numbering may not correspond to that shown on separate Service Kit leaflets. For Service Kit Part Number see www.knorr-bremsecvs.com 7

Service Steps Disassembling Step Service task Remove the retaining ring (5) while holding the cover (4) against the compression spring (2). 2 Remove the cover (4) carefully. 3 Remove the compression spring (2). 4 Remove the piston (). 5 Remove the old O-ring (3) from cover (4), and clean the cover (4). 6 Clean the purge valve housing in the body. Assembling Step Service task Lubricate the purge valve housing with grease. 2 Place the new piston assembly () into the housing. 3 Insert the new compression spring (2). 4 Lubricate new O-ring (3) with grease and fit into the groove in cover (4). 5 Place the assembled cover (4) into the housing and press down against the compression spring (2). 6 Fit new retaining ring (5), making sure that it is securely located in the groove. 7 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. 8 Charge the air system to just below cut-out pressure and check the new piston for leakage. Air must not leak through port 3 and silencer. 8

3.7 Disassembling and Assembling the Tyre Inflator (F) Part Identification Item Description Qty Compression spring 2 Valve tappet 3 Sealing ring 4 O-ring (7 x,5) 5 Threaded connector 6 Protective cap 2 4 3 5 Note that component numbering may not correspond to that shown on separate Service Kit leaflets. 6 For Service Kit Part Number see www.knorr-bremsecvs.com Service Steps Disassembling Step Service task Remove the rubber protective cap (6). 2 Screw-out the threaded connector (5) with sealing ring (3). 3 Remove the valve tappet (2) if it does not come out with the threaded connector (5). 4 Remove the compression spring (). 5 Clean the tyre inflator housing in the body. Assembling Step Service task Place the new compression spring () into the tyre inflator housing. 2 Lubricate new O-ring (4) with grease and fit into the groove in the valve tappet (2). 3 Lubricate the new assembled valve tappet (2) with grease. 4 Place the assembled valve tappet (2) into the new threaded connector (5). 5 Fit the new (metallic) sealing ring (3) to the threaded connector (5) and screw-in. 6 Tighten the threaded connector (5) to a torque of 50 Nm 7 Check operation by pushing valve tappet (2) twice. 8 Fit the new rubber protective cap (6). 9 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. 0 Charge the air system to just below cut-out pressure and check the new tyre inflator for leakage. 9

3.8 Replacement of the Double Pressure Sensor (H) Part Identification Item Description Qty O-ring 2 2 Screw 2 3 Double pressure sensor assembly Note that component numbering may not correspond to that shown on separate Service Kit leaflets. For Service Kit Part Number see www.knorr-bremsecvs.com 3 Service Steps 2 Step Service task Removal of the double pressure sensor. Remove the two screws (2). 2 Remove the double pressure sensor (3) and the two O-rings (). 3 Carefully clean the O-ring sealing surfaces. Replacement of the double pressure sensor Lubricate the two new O-rings () and place them into the body. 2 Push the new double pressure sensor (3) into the body and firmly hold in place against the O-rings () until the new screws (2) are fitted and fully tightened to a torque of 6 Nm. 3 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. 4 Prior to returning the vehicle to service, check the new double pressure sensor for function and electrical connection: during charging the air system, check the pressure signal on the dashboard. 20

3.9 Removal and Replacement of the Time Switch Piston (I) Part Identification Item Kit Description Qty Piston (complete with K-ring) 2 O-Ring 3 Compression spring 4 Cover 5 Screw 4 included in kit Note that component numbering may not correspond to that shown on separate Service Kit leaflets. 2 3 For Service Kit Part Number see www.knorr-bremsecvs.com 4 5 Service Steps Step Service task Removal of the time switch Undo the four screws (5) while holding the cover (4) against the compression spring (Fig. ). 2 Remove cover (4) and O-ring (2) (Fig. 2). 3 Remove compression spring (3). 4 Remove piston () (Fig. 3). 5 Clean the cover (4) using a soft cloth. 6 Clean inside the housing with a soft cloth. Pay attention not to contaminate the nozzle in the housing. 4 5 4 2 3 Fig. Fig. 2 Fig. 3 2

Step Service task Installation of the time switch Check that the sliding surfaces in the body and cover (4) are clean. 2 Lubricate new O-ring (2), inside wall and sealing surface of cover (4), and central bore of housing with grease (Fig. 4). 3 Fit new O-ring (2) into cover (4) (Fig. 5). 4 Align the new piston () K-ring centrally on the piston (Fig. 6). 5 Push the piston () carefully into cover (4) to fully centralise the K-ring (Fig. 7). 6 Pull out piston () from cover (4) without displacing the K-ring. 7 Push piston () into housing, again without displacing the K-ring (Fig. 8). 8 If the K-ring moves out of alignment from a concentric position, start again from Step 4. 9 Place compression spring (3) onto piston () (Fig. 9). 0 Carefully place cover (4) onto housing and push it down until it is correctly seated - pay attention to keep correct alignment of K-ring within cover (4) (Fig. 0). Hold cover (4) down against compression spring (3) and fit screws (5) (Fig. ). 2 Tighten screws (5) to a torque of 6 Nm. 3 Refit (if necessary) the air processing unit to vehicle and check according to chapter 3.0. 4 Charge the air system until cut-out pressure is reached. During charging check the device generally for leakage. After cut-out, stop the engine and check if the regeneration air exhausting at port 3 stops within a maximum of 40 seconds from the time of cut-out. 2 2 4 4 Fig. 4 Fig. 5 Fig. 6 4 3 Fig. 7 Fig. 8 Fig. 9 22

4 4 5 Fig. 0 Fig. 3.0 Refitting the Air Processing Unit to the Vehicle Recommended Tightening Torques for Air Ports Conventional face sealing metric ports Max. torque [Nm] M2 x.25 25 M2 x.5 25 M2 x.75 25 M6 x.5 45 M22 x.5 60 Fig. Fig. 2 Service Steps Step Service task Locate the air processing unit in its position on the vehicle. 2 Fit and tighten the three M2 mountings (bolts, Fig. or nuts, Fig. 2) to a maximum torque of 25 Nm. Reinstall the air lines taking great care to ensure correct connection to ports. See above table for recommended 3 tightening torques. 4 Charge the air system to cut-out pressure. 5 Check all fittings and seals for leakage using soap and water. There should be no leakage. 6 Deplete the pressure in the system by operating the foot brake repeatedly until cut-in pressure is reached. 7 Ensure cut-in and cut-out pressures are correct (refer to vehicle manufacturer). 23

Commercial Vehicle Systems Head Office Systeme für Nutzfahrzeuge GmbH Moosacher Strasse 80 80809 Munich Germany Tel: +49 89 3547-0 Fax: +49 89 3547-2767 www.knorr-bremsecvs.com Doc.- No. Y025030 (EN - Rev. 002) February 203 Europe Africa Austria GmbH Systeme für Nutzfahrzeuge Mödling Tel: +43 2236 409-2436 Fax: +43 2236 409-2434 Belgium Benelux B.V.B.A. Heist-op-den-Berg Tel: +32 525 7900 Fax: +32 524 9240 Czech Republic Systémy pro uzitková vozidla, CR, s.r.o. Liberec Tel: +420 482 363-6 Fax: +420 482 363-7 France Systèmes pour Véhicules Utilitaires France Lisieux Cedex Tel: +33 2 332 200 Fax: +33 2 332 303 Germany Hasse & Wrede GmbH Berlin Tel: +49 30 9392-30 Fax: +49 30 7009-08 Germany Systeme für Nutzfahrzeuge GmbH Berlin Tel: +49 80 223-7637 Fax: +49 30 9392-3426 Hungary Fékrendszerek Kft. Kecskemét Tel: +36 76 5 00 Fax: +36 76 48 00 Italy Sistemi per Autoveicoli Commerciali S.p.A. Arcore Tel: +39 039 6075- Fax: +39 039 6075-435 Netherlands Benelux B.V.B.A. Mydrecht Tel: +3 297 239-330 Fax: +3 297 239-339 Poland Polska SfN Sp. z o.o. Warsaw Tel: +48 22 887-3870 Fax: +48 22 53-470 Russia RUS Nizhniy Novgorod Tel: +7 832 57-666 Fax: +7 832 57-679 Russia Systeme für Nutzfahrzeuge LLC Moscow Tel: +7 495 234-4995 Fax: +7 495 234-4996 South Africa S.A. Pty. Ltd. Kempton Park Tel: +27 96-7800 Fax: +27 975-8249 Spain Bost Ibérica, S.L. Irun (Guipuzcoa) Tel: +34 902 00-569 Fax: +34 943 64-063 Sweden System for Tunga Fordon AB Lund Tel: +46 46 440 005 Fax: +46 46 4897 Switzerland Systeme für Nutzfahrzeuge GmbH Bassersdorf Tel: +4 44 888 77-55 Fax: +4 44 888 77-50 Turkey Ticari Araç Fren Sistemleri Tic. Ltd. Sti. Findikli - Istanbul Tel: +90 22 293-4742 Fax: +90 22 293-4743 United Kingdom Systems for Commercial Vehicles Ltd. Bristol Tel: +44 7 9846-00 Fax: +44 7 9846-0 America Brazil Sistemas para Veículos Comerciais Brasil Ltda. São Paulo Tel: +55 568 04 Fax: +55 5686 3905 USA Bendix Commercial Vehicle Systems LLC Elyria, OH Tel: + 440 329-900 Fax: + 440 329-905 Asia Australia Australia Australia Pty. Ltd. Granville NSW Tel: +6 2 8863-6500 Fax: +6 2 8863-650 China Brake Equipment (Shanghai) Co. Ltd. Shanghai Tel: +86 2 3858-5800 Fax: +86 2 3858-5900 China Asia Pacific (Holding) Limited Commercial Vehicle Systems Division Hong Kong Tel: +852 3657-9800 Fax: +852 3657-990 India Systems for Commercial Vehicles India Private Ltd. Pune Tel: +9 20 6674-6800 Fax: +9 20 6674-6899 Japan Commercial Vehicle Systems Japan Ltd. Saitama Tel: +8 49 273-955 Fax: +8 49 282-860 Korea Korea Ltd. Truck Brake Division Seoul Tel: +82 2 2273-82 Fax: +82 2 2273-84 The information contained herein is subject to alteration without notice and therefore may not be the latest release. Please check our website www.knorr-bremsecvs.com for the latest update or contact your local representative. The figurative mark K and the trademarks KNORR and KNORR-BREMSE are registered in the name of AG. Additional terms and conditions apply; please refer to our website knorr-bremsecvs.com for full Disclaimer. Note: If service work is carried out on a vehicle based on information provided herein, it is the responsibility of the workshop to ensure the vehicle is fully tested and in full functional order before the vehicle is returned into service. accepts no liability for problems caused as a result of appropriate tests not being carried out. Copyright AG - all rights reserved, including industrial property rights applications. AG retains any power of disposal, such as for copying and transferring. Munich, Germany Tel:+49 89 3547-0 Fax:+49 89 3547-2767 www.knorr-bremse.com, www.knorr-bremsecvs.com Group