BENDIX BW2539 User's Manual
Contents
1. CONTROL PORT CONTROL PORT CAP NUT VENT PORT DELIVERY MOUNTING HOLES SUPPLY PORT CAP NUT FIGURE 1 SS 1 SHUT OFF VALVE DESCRIPTION The SS 1 shut off valve figure 1 is a pilot operated air controlled on off non graduating non exhausting pneumatic control valve The valve is primarily used to delay sequence or control airflow from various devices in the air brake system It can be operated either in a pilot or automatic mode using different air connection methods The SS 1 valve is a general purpose valve used in a variety of applications on trucks buses tractors trailers and converter dollies It is offered in a variety of pressure settings to accommodate applications where automatic operation is required The most common application of the SS 1 valve is in the tractor protection system of a truck tractor Important Note The SS 1 shut off valve is application specific due to its pressure settings It is therefore important to use the proper part number when replacement is required IN ADDITION The SS 1 shut off valve and SV 1 synchro valves are identical in appearance and similar in operation but have substantial internal differences and must not be confused or used interchangeably The SV 1 synchro valve incorporates an internal exhaust passage through its piston which allows delivery pressure to be vented to atmosphere while the SS 1 does not Refer to Service Data Sheet SD 03 4020 for m2. ations and systems 9 Components with stripped threads or damaged parts should be replaced rather than repaired Do not attempt repairs requiring machining or welding unless specifically stated and approved by the vehicle and component manufacturer 10 Prior to returning the vehicle to service make certain all components and systems are restored to their proper operating condition 11 For vehicles with Antilock Traction Control ATC the ATC function must be disabled ATC indicator lamp should be ON prior to performing any vehicle maintenance where one or more wheels on a drive axle are lifted off the ground and moving OPERATING AND LEAKAGE TESTS OPERATING TESTS General Two accurate air gauges are necessary to perform these tests Depending upon installation it may be necessary to remove the valve to properly test it When testing valves installed in an automatic application the correct opening pressures of the valve should be known before beginning tests consult vehicle manual Refer to figure 3 and use the appropriate Operational test Pilot 1 Install an accurate gauge in the supply line and the other gauge in the delivery line 2 With full system pressure present at the supply port of the SS 1 valve apply and release full system pressure to the control port and note that delivery pressure increases to supply port pressure with no perceptible lag 3 With full system pressure present at the control port
3. c application requirements PREVENTIVE MAINTENANCE Important Review the Bendix Warranty Policy before performing any intrusive maintenance procedures The warranty may be voided if intrusive maintenance is performed during the warranty period No two vehicles operate under identical conditions as a result maintenance intervals may vary Experience is a valuable guide in determining the best maintenance interval for air brake system components At a minimum the SS 1 valve should be inspected every 6 months or 1500 operating hours whichever comes first for proper operation Should the SS 1 valve not meet the elements of the operational tests noted in this document further investigation and service of the system or valve may be required If the SS 1 valve fails to function as described or leakage is excessive it should be replaced with a genuine Bendix service unit of the same part number available at Bendix authorized parts outlets WARNING PLEASE READ AND FOLLOW THESE INSTRUCTIONS TO AVOID PERSONAL INJURY OR DEATH When working on or around a vehicle the following general precautions should be observed at all times Always wear safety glasses 1 Park the vehicle on a level surface apply the parking brakes and always block the wheels 2 Stop the engine and remove ignition key when working under or around the vehicle When working in the engine compartment the engine should be shut off and the ign
4. d delivery ports Apply a soap solution around control port cap nut and supply port cap nut No leakage is permitted Apply soap solution to the exhaust port leakage must not exceed a 1 bubble in less than 5 seconds 100 sccm Excessive leakage would indicate faulty piston o rings 2 Apply 120 psi to the supply port only Apply soap solution to the exhaust port Leakage must not exceed a 1 bubble in less than 5 seconds 100 sccm Excessive leakage would indicate a faulty inlet valve or inlet valve seat If the SS 1 valve does not function as described or if leakage is excessive it is recommended that it be replaced with a new unit available from authorized genuine Bendix parts outlets REMOVING AND INSTALLING REMOVING 1 Read the Warning Section previously presented in this manual and make certain to block and hold vehicle by means other than air brakes Drain the air brake system completely 3 Clean the exterior of the SS 1 shut off valve as well as the fittings and air lines attached to the valve Identify the air lines to facilitate reinstallation disconnect the lines remove and retain the mounting bolts and then the valve Remove the exhaust check from the vent port if the shut off valve was so equipped INSTALLING 1 endix Mount the SS 1 valve securely using the mounting hardware retained during removal Using the identification made during removal connect the air lines
5. d from the control port the piston return spring moves the piston away from the inlet valve As the piston moves the inlet valve re seats itself preventing airflow to the delivery port If air pressure at the supply port remains constant is not reduced then delivery port pressure remains equal to supply port pressure provided that devices connected to it do not dissipate delivery port pressure If supply port pressure is removed after control pressure is removed then delivery port air pressure will hold the inlet valve away from its seat against the force of the inlet valve return spring Air present at the delivery port will flow through the valve body in the reverse direction from the delivery port past the inlet valve and into the supply port Flow will continue until the delivery port pressure which acts upon the area of the inlet valve is reduced and equal to the force exerted by the inlet valve spring When delivery port pressure and spring force are equal the inlet valve re seats in the body and air pressure remaining in the delivery line is trapped between the closed inlet valve and air devices connected to the delivery port The amount of 2 CONTROL VALVE SS 1 VALVE RESERVOIR RESERVOIR Pilot Operation TRACTOR PROTECTION CONTROL VALVE SUP HOSE COUPLING DOUBLE GLAD HAND BRAKE VALVE CHECK VALVE Pilot Operation Tractor Protection Application SS 1 VALVE RESERVOIR Automatic Operation Comm
6. ition key should be removed Where circumstances require that the engine be in operation EXTREME CAUTION should be used to prevent personal injury resulting from contact with moving rotating leaking heated or electrically charged components 3 Do not attempt to install remove disassemble or assemble a component until you have read and thoroughly understand the recommended procedures Use only the proper tools and observe all precautions pertaining to use of those tools 4 Ifthe work is being performed on the vehicle s air brake system or any auxiliary pressurized air systems make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle If the vehicle is equipped with an AD IS air dryer system or a dryer reservoir module be sure to drain the purge reservoir 5 Following the vehicle manufacturer s recommended procedures deactivate the electrical system in a manner that safely removes all electrical power from the vehicle 6 Never exceed manufacturer s recommended pressures 7 Never connect or disconnect a hose or line containing pressure it may whip Never remove a component or plug unless you are certain all system pressure has been depleted 8 Use only genuine Bendix replacement parts components and kits Replacement hardware tubing hose fittings etc must be of equivalent size type and strength as original equipment and be designed specifically for such applic
7. nnection methods that can be used In general the SS 1 valve can either be connected in the system to function as a pilot operated remote mounted on off valve or it can be connected in a manner that allows the valve to operate automatically at preset pressures as system pressure increases or decreases Figure 3 displays examples of air system connections Two examples of connections that result in pilot operation are shown and one that illustrates automatic operation It should be noted that since the SS 1 valve is a pressure sensitive valve under certain air system conditions it might temporarily operate in an automatic fashion even in a system where its intended function is that of a pilot on off valve Regardless of how the SS 1 shut off valve is connected the internal valve operation is the same PILOT controlled remotely by another valve With no air pressure present at the control port supply port air pressure if present along with the inlet valve spring hold the inlet valve on its seat in the body The piston is held away from the inlet valve by the piston return spring When sufficient air pressure is applied to the control port the control piston moves against the resistance of its return spring As the control piston moves it contacts the valve and continued piston movement drives the inlet valve from its seat and allows supply air to flow through the body and out the delivery port When air pressure is remove
8. on Control amp Supply FIGURE 3 TRACTOR PROTECTION SYSTEM air pressure trapped is dependant upon the specific part number of the valve Valves used in a tractor protection system application will trap less than 5 psi while other SS 1 valves will trap approximately 10 psi AUTOMATIC self actuating at a preset pressure Automatic operation of the SS 1 shut off valve occurs when the pressure at the supply and control port is the same This is referred to as common control and supply and can be accomplished by connecting the valve s control port to its supply port using a pipe or tubing tee With common control and supply pressure the valve opens delivers air on ascending air pressure and closes on descending pressure The pressures at which delivery and closure occur differ for various part numbers Opening and closing pressures are specified for the various part numbers It should be noted that as supply and control pressure descends delivery pressure will also decrease but will not be completely removed Refer to the Pilot operation in this section Important Consult Bendix cataloging and or Bendix Engineering for specific opening and closing control pressures when the SS 1 valve is used in the automatic mode When using the SS 1 _ shut off valve in this manner the control signal ramp rate should be limited by orificing or other methods Please contact Bendix Engineering with specifi
9. ore information on the SV 1 synchro valve Service Data Sheets can be obtained by calling 1 800 AIR BRAKE or by visiting www bendix com on the Internet 1 4 P T CONTROL PORT PISTON CAP NUT O RING PISTON RETURN PISTON O RING SPRING VENT PLUG WITH 1 8 P T VENT TM PISTON O RING 1 4 P T DELIVERY PORT i MOUNTING HOLE P i je HT INLET VALVE INLET VALVE SPRING CAP NUT O RING 4 4 PT SUPPLY PORT Two 28 inch mounting holes are provided in the die cast zinc body for panel or frame mounting Two steel hex cap nuts at the ends of the cylindrical valve body retain the internal components All air connection ports contain pipe threads Lettering embossed in the valve body identifies two of the four ports in the valve Refer to the chart below and figure 1 Body Ident Thread Size IMPORTANT A vented socket head vent plug is installed in some SS 1 valves however an exhaust check valve should be installed in the threaded vent port when the SS 1 valve is mounted outside the cab in unprotected environments See Figure 2 1 8 PIPE THREAD N Note Either style may be installed in the SS 1 valve FIGURE 2 EXHAUST CHECK VALVE STYLES OPERATION GENERAL Because the SS 1 shut off valve is a general purpose valve it can be connected in the air system in a variety of ways to accomplish its intended function Figure 3 displays only three of the many different co
10. remove all pressure from the supply port Note that delivery port pressure is reduced to 10psi or less Important Note Depending upon part number and valve application on the vehicle delivery port pressure may be required to be reduced to less than 5psi When used in tractor protection systems delivery pressure is generally required to be less than 5psi in this test Consult the vehicle manual for specifications Automatic 1 3 Install an accurate gauge in the common control and supply line install another gauge in the delivery line Gradually increase air pressure to the common supply and control line Note when pressure is first registered on the delivery line gauge and record the common control and supply pressure at that point Compare the recorded pressure with specifications in vehicle manual or for the valve part number being tested The recorded pressure should be plus or minus 7psi of the specified pressure Apply full system pressure to the common control and supply and note that delivery pressure increases to supply port pressure with no perceptible lag Remove all pressure from the common control and supply Note that delivery port pressure is reduced to 10psi or less Important Note Depending upon part number and valve application on the vehicle delivery port pressure may be required to be reduced to less than 5psi LEAKAGE TESTS ALL TYPES 1 With 120 psi air pressure present in supply control an
11. to the SS 1 valve Install the exhaust check valve if the SS 1 shut off valve was So equipped Perform tests as outlined in the Operating and Leakage Tests section before placing the vehicle back into service BW2539 2006 Bendix Commercial Vehicle Systems LLC All rights reserved 1 2006 Printed in U S A
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