User manual BENDIX TC-4 MODULATING CONTROL VALVE

[. . . ] Experience is a valuable guide in determining the best maintenance interval for air brake system components. At a minimum, the TC-4TM valve should be inspected every 6 months or 1500 operating hours, whichever comes first, for proper operation. Should the TC-4TM valve not meet the elements of the operational tests noted in this document, further investigation and service of the valve may be required. Check for proper operation before placing vehicle in operation. OPERATING AND LEAKAGE TESTS If valve is to be tested on vehicle, block the vehicle wheels. [. . . ] With air exhausted from the service (control) port of the relay valve, the relay valve responds, exhausting the air from the spring brakes (allowing the brakes to apply). With sufficient air pressure in the emergency/parking reservoir, modulation of the spring brake application is possible; the amount of braking force governed by the position of the TC-4TM valve lever. With reference to Figure 2, note that the exhaust of the TC-4TM valve is connected to a delivery line of the foot brake valve. This prevents the compounding of spring brake and service brake application forces on the slack adjusters. NOTE: The valve is correctly modulating the brake application. If the valve does not function as described, or if leakage is excessive, it is recommended that it be replaced with a new or remanufactured unit or repaired with genuine Bendix parts available at Bendix outlets. 2. Install shims (11 ) and graduating spring (12). Install piston return spring (14) on piston; holding this assembly vertical, place the body over the top of the piston assembly, then turn over letting the assembly fall into place. Install the torsion spring (8) over the lever (7) noting that parts are in correct relation to body as previously marked. Place the ends of the torsion spring (8) in holes in the body. Check for correct handle assembly by noting the torsion spring and handle assembly will move the piston past the inlet seat surface. (This can be seen by looking at the supply port end of the valve. ) If handle is not assembled into body correctly, reassemble. Install inlet valve (4) and inlet valve spring (3). Install sealing ring (2) on cap nut (1); install cap nut (Torque to 50-100 inch pounds. ) 10. Install disc (6) in locking button (5) and install button into valve. Test valve as outlined in "Operating and Leakage Test" section. REMOVING AND INSTALLING REMOVING Block and hold vehicle by means other than air brakes. Identify air lines to TC-4TM valve to facilitate installation; disconnect lines. Mount valve securely with two mounting screws. Identify and connect air lines to valve. Remove cap nut (1) and cap nut sealing ring (2). Remove inlet valve spring (3) and inlet valve (4). Remove locking button (5) and rubber friction disc (6). Mark lever (7) in relation to body and torsion spring (8) in relation to handle so that proper position can be determined during assembly. [. . . ] 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 only genuine Bendix ® replacement parts, components and kits. [. . . ]