Document oDvLvp0kwLREB6RmZYxrkjOJ8

CHECK-OUT OF AIR BRAKE SYSTEMS PUBLISHED AS A SERVICE TO FLEET OPERATORS BY Copyright 1964 SPNY 005961 jst --,*r-^ I- N_G<; SCF-ABEX-0875 J PROCEDURE FOR COMPLETE A RECOMMENDED BY All equipment, even identical installations, should be checked out before going into service, out again, regularly, as part of standard preventive maintenance. The same procedure cat confirm driver complaints. Proper testing saves many hours of work and many unnecessa. All the equipment required can be made easily from parts on hand. The first too! requires ( gage of known accuracy, drain cock, shut-off cock and another glad hand. The second tool i of known accuracy, flexible hose and a male and female tee fitting. (This Completely drain all air tanks in the sys tem. At the time the drain cocks are open, hold a hand below it to determine if there is excess oil or contamination. If this is found, take the necessary measures to ! correct the source of difficulty. Install the check gage with glad hands in the emergency air line and dose the shut off cock. Do not connect service line at this time. Start engine. With no air pressure in sys tem apply foot valve and note when stop lights light, which should be approxi mately 5 PSI. Release foot valve and continue to charge system. Time required for pressure build-up to governor cut-out between 100-105 PSI should not exceed 5 minutes. At the same time, low pressure warning device- should remain on until the pressure has built up to approximately 60 PSI. At this point, the warning buzzer must, stop sounding or the warning light must go out. As the pressure builds up, check the accuracy of the gage in the cab with that of the test gage.. Make sufficient brake applications to re duce the air pressure to the point where the governor should cut in between 80-85 PSI, resuming compression. With the engine stopped, let air out of the wet tank and watch the gage in the cab. The gage should read the pressure in the dry tank and thus it should remain con stant. This determines that the one way - check valve between the dry tank and the wet tank is holding pressure. Attach the service line to the trailer and open shut-off cock. Start engine and charge the complete system up to the pressure of governor cut out. Stop the engine. Apply full pressure to the brakes through the foot pedal. At this point all the lines are fully charged and the system is under maximum pressure. Now go around all the air lines and listen, you may hear a leak at any of the valves, fittings, bends or chambers. Start at the compressor and while listening, look. Watch for sharp bends in the lines. Notice that no tubing is squashed to slow down the flow of air, see that hoses are in good condition. With the brakes fully applied, .pressure drop should not exceed three pounds per minute. With full governor cut out pressure and the brakes released, the drop should not exceed two pounds per minute. - Apply emergency control valve in cab. See that the trailer brakes are set up and the tractor air is retained. This checks the tractor protection system. SPNY 005962 cBRAKE SYSTEM CHECK-OUT IH should be checked e effectively used to costly replacements. ilad hand, tee, an air ven simpler--a gage jcedure will require two men for best results.) Insert separate test gage between trailer brake hose and a brake chamber. Open drain cock wide. Note reading on gage at brake chamber. This is the full emergency pressure if the trailer breaks away or when the trailer is spotted. Note reading on dash board gage. This is the tractor pressure you would have left after the break away or after spotting a trailer. Start engine, close drain cock, open shut off cock, charge trailer brakes, and fill air system to governor cut off pressure. Open drain cock slightly to simulate a leak in the tractor system. Read gage on the test tool when the trailer brakes go into emergency. If you do not have con trolled emergency application pressure on the relay emergency valve, read gage at trailer brake to see what braking pressure you would have in case of a tractor leak. Read dash board gage to see what pres sure you would retain in the tractor in the event of a leak. If the relay emergency valve has controlled emergency pressure, then note test tool gage pressure when the trailer brakes start to apply. Note test tool gage pres sure when the trailer brakes are fully applied. On this slow leak test, if trailer brakes do not apply, you do not have a no-bleedback relay emergency valve. Put test tool in service line and connect up the emergency line glad hands. Close the drain cock, open the shut-off cock and charge the trailer brakes to governor cut out pressure. Apply foot pedal fully. Read test tool gage. It will tell you what pressure the foot valve is able to pass. It will also tell what pressure is being applied to the relay emergency valve. Read gage at brake chamber. This will tell if the relay emer gency valve is passing all the pressure it receives. Release foot valve and apply hand valve to mnYiTnuTn position. Read pressure at test tool gage. It will tell you what pres sure the hand valve is able to pass. Release hand valve application. Remove test tool but do not join up the service line glad hands. Apply hand valve and notice how long it takes before the relay emer gency valve goes into emergency. For a complete brake system check, the pressure in at least one chamber of each axle should be checked against application pressure. At the same time, checking each slack adjuster and chamber for proper movement and adjustment. SPNY 005963 AMERICAN BRAKEBLOK HIGH CAPACITY FRICTION MATERIALS... The Result of 60 Years of Engineering, Formulating and Manufacturing to the Highest Standards of The Industry American Brakeblok brake linings are formu lated to deliver STOPPING POWER for multi stop operation in light through extra heavyduty trucks . . . over all types of terrain . . . in all climates. Known to the trucking industry as "America's Safety Brake Lining", American Brakeblok offers the extra advantage of nationwide, im mediate availability. Wherever your trucks and trailers operate, in every state, American Brake blok replacement linings are available from NAPA jobbers--your best source of supply for automotive replacement parts. Call your NAPA jobber. Ask him to survey your equipment, and show you the American Brakeblok linings that are engineered speci' fically for your requirements. For information as to the locations of NAPA jobbers write to: Light and Heavy-Duty Strip ABB Thick Blocks FRICTION MATERIALS GROUP 900 W. Maple Road, Troy, Michigan 48084 I UTHO IN U.S.A. SPNY 005964 Form C299--25M-7/64