User manual BENDIX R-12-R-14 RELAY VALVES

[. . . ] For ease of servicing, the inlet/ exhaust valve can be replaced without the need for line removal. EXHAUST OR RELEASE When air pressure is released from the service port and air pressure in the cavity above the relay piston is exhausted, air pressure beneath the piston lifts the relay piston and the exhaust seat moves away from the exhaust valve, opening the exhaust passage. With the exhaust passage open, the air pressure in the brake chambers is then permitted to exhaust through the exhaust port, releasing the brakes. OPERATION APPLICATION Air pressure delivered to the service port enters the small cavity above the piston and moves the piston down. The exhaust seat moves down with the piston and seats on the inner or exhaust portion of the inlet/exhaust valve, sealing off the exhaust passage. At the same time, the outer or inlet portion of the inlet/exhaust valve moves off its seat, permitting supply air to flow from the reservoir, past the open inlet valve and into the brake chambers. ANTI-COMPOUNDING (SIMULTANEOUS SERVICE AND PARK APPLICATION) In those applications where the R-14TM relay valve is used to control spring brake chambers, the anti-compound feature may be utilized. [. . . ] Coat the exhaust port with a soap solution; a 1" bubble in 3 seconds leakage is permitted. Coat the outside of the valve where the cover joins the body to check for seal ring leakage; no leakage is permitted. If the R-14TM valve is used to control the spring brakes, place the park control in the released position and coat the balance port with a soap solution to check the diaphragm and its seat. Leakage equivalent to a 1" bubble in 3 seconds is permitted. Note: If the anti-compound feature is in use, the line attached to the balance port must be disconnected to perform this test. If the valves do not function as described above, or if leakage is excessive, it is recommended that the valves be replaced with new or remanufactured units or repaired with genuine Bendix parts, available at any authorized Bendix parts outlet. DISASSEMBLY Note: Prior to disassembly, mark the location of the mounting bracket to the cover and the cover to the body. Remove the four (4) cap screws and lockwashers securing the cover to the body. Remove the cover, sealing ring, and mounting bracket. Remove the piston and o-ring from the body. While depressing the exhaust cover, remove the retaining ring and slowly relax the spring beneath the exhaust cover. Remove the exhaust cover assembly and o-rings. Remove the inlet/exhaust valve return spring from the body. Remove the inlet/exhaust valve from the body. Remove the valve retainer from the inlet/exhaust valve. Remove the Phillips head screw and exhaust cover from the R-14TM valve cover. Remove the service port cap nut and o-ring from the R-14TM valve. Remove the diaphragm from the R-14TM valve cover. CLEANING AND INSPECTION 1. Wash all metal parts in mineral spirits and dry them thoroughly. (Note: When rebuilding, all springs and all rubber parts should be replaced. ) 2. Inspect all metal parts for deterioration and wear, as evidenced by scratches, scoring and corrosion. Inspect the exhaust valve seat on the relay piston for nicks and scratches which could cause excessive leakage. Inspect the inlet valve seat in the body for scratches and nicks, which could cause excessive leakage. [. . . ] Test the valves as outlined in the Operational and Leakage Test section before returning the valve to service. 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. Park the vehicle on a level surface, apply the parking brakes, and always block the wheels. Stop the engine and remove ignition key when working under or around the vehicle. [. . . ]