BENDIX BW1594 User's Manual
Contents
1. Bendix SL 5 Stop Light Switch amp Bendix DS 2 Combined Stop Light Switch amp Double Check Valve LEAF SPRING FULCRUM CONTACT STRIP SHORTING BAR TERMINAL RIVET PISTON DIAPHRAGM SHUTTLE OUTLET PORT FIGURE 1 DS 2 COMBINED STOP LIGHT SWITCH amp DOUBLE CHECK VALVE SECTIONAL DESCRIPTION The Bendix SL 5 stop light switch is an electro pneumatic 5 psi non grounded switch that operates in conjunction with the brake valve and stop lights by completing the electrical circuit and lighting the stop lights when a brake application is made The DS 2 combined stop light switch and double check valve as the name implies combines a SL 5 stop light switch with a DC 4 double check valve to perform the function of both It operates in conjunction with the brake valve and hand control valve by directing the flow of air from whichever delivers the higher pressure into a common delivery line and to the stop light switch closing the electrical circuit to the stop lamps The stop light switch can be used with either 12 or 24 volt systems The stoplight switch is not a serviceable item and if found defective in either device the complete unit must be replaced The shuttle valve in the DS 2 valve is serviceable and may be replaced Both the SL 5 switch and the DS 2 valve have been tested and meet the requirements of FMVSS 121 OPERATION The stop switch mechanism is identical in th2. and always block the wheels Always wear safety glasses 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 ignition 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 10 11 If the work is being performed on the vehicle s air brake system or any auxiliary pressurized air systems make certain to drain the air pressure from all reservoirs before beginning ANY work on the vehicle If the vehicle is equipped with an AD IS air dryer system or a dryer reservoir module be sure to drain the purge reservoir Following the vehicle manufacturer s recommended procedures deactivate the electrical system in a manner that safely removes all electrical power from the vehicle Never exceed manufacturer s recommended pressures 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 Use onl
3. e SL 5 switch and the DS 2 valve When a brake application is made air pressure from the brake valve enters the cavity below the diaphragm The air pressure below the diaphragm moves the piston until it contacts the leaf spring The leaf spring travels past a fulcrum at which point the leaf springs snaps a shorting bar which mates with the contact strips The stop light electrical circuit 1 is completed lighting the stop lights before the brake application pressures reach 6 psi The snap action spring design minimizes arcing The double check valve is activated by air being introduced through either of the two 2 inlet ports The greater pressure pushes the shuttle along its guides and closes the opposite inlet port The air is then directed out the common delivery line and to the stop light switch PREVENTIVE MAINTENANCE Important Review the Bendix Warranty Policy before performing any intrusive maintenance procedures A 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 DS 2 SL 5 valve should be inspected every 6 months or 1500 operating hours whichever comes first for proper operation and electrical connections Should the DS 2 SL 5 valve not meet t
4. e the DS 2 valve INSTALLING 1 Replace the SL 5 switch or DS 2 valve in the port from which it was removed Do not install with the terminals pointing down 2 Secure electrical connections 3 Reinstall air line connections to DS 2 valve DISASSEMBLY Double Check Valve 1 Remove three cap screws and cap 2 Remove o ring seal from cap 3 Remove shuttle valve CLEANING AND INSPECTION 1 Blow dust or other foreign material out of body Do not immerse in cleaning fluid 2 Inspect shuttle valve and o rings for excessive wear or deterioration Inspect valve seats for nicks or burrs Replace all parts that were discarded and any parts not founds to be serviceable during inspection using only genuine Bendix replacement parts ASSEMBLY Before assembling the DS 2 double check valve lubricate all o rings and o ring grooves with Bendix silicone lubricant Pc No 291126 or equivalent NOTE When using pipe thread sealant during assembly and installation take particular care to prevent the sealant from entering the valve itself Apply the sealant beginning with the second thread back from the end TEST Repeat Operating and Leakage Test 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 1 Park the vehicle on a level surface apply the parking brakes
5. he elements of the operational tests noted in this document further investigation and service of the valve may be required OPERATING AND LEAKAGE TEST 1 Install an accurate air gauge in the service line or brake chamber Apply brake valve gradually Stop lamps should light at 6 psi or less and go out after the brake application is released This checks the electrical function of the stop light switch in either the SL 5 switch or DS 2 valve 2 DS 2 valve only Apply the foot valve and coat the exhaust port of the hand valve or other alternate source Reverse the above applying the hand valve or other alternate source and coat the exhaust port of the foot valve In either mode a leakage of not more than a 1 bubble in 5 seconds is permissible 3 SL 5 switch or DS 2 valve When pressurized no leakage is permitted from the body of the valve or switch If the SL 5 switch or DS 2 valve does not function as described above or if leakage is excessive the valve or switch should be replaced with a new unit or in the case of the double check portion of the DS 2 valve repaired with genuine Bendix parts REMOVING AND INSTALLING REMOVING 1 Block vehicle wheels or hold by means other than vehicle service brakes 2 Disconnect electrical connections from terminal screws 3 SL 5 switch Remove the switch using a wrench on the hex portion of the body 4 DS 2 valve Disconnect air lines and remov
6. y 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 applications and systems 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 Prior to returning the vehicle to service make certain all components and systems are restored to their proper operating condition For vehicles with Antilock Traction Control ATC the ATC function must be disabled ATC indicator lamp shoud be ON prior to performing any vehicle maintenance where one or more wheels on a drive axle are lifted off the ground and moving BW1594 2006 Bendix Commercial Vehicle Systems LLC All rights reserved 7 2006 Printed in U S A
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