User manual BENDIX E-10 DUAL BRAKE VALVES

[. . . ] The air pressure moves the relay piston, which contains the exhaust seat and closes the secondary exhaust valve. As the secondary exhaust valve closes, the secondary inlet valve is moved off its seat allowing the secondary air to flow out the secondary delivery port. Because of the small volume of air required to move the relay piston, action of the secondary circuit of the valve is almost simultaneous with the primary circuit portion. delivery ports, the primary piston will mechanically move the relay piston, allowing the piston to close the secondary exhaust valve and open the secondary inlet valve and allow air to flow out the secondary delivery port. BALANCED: PRIMARY CIRCUIT When the primary delivery pressure acting on the piston equals the mechanical force of the brake pedal application, the primary piston will move and the primary inlet valve will close, stopping further flow of air from the primary supply line through the valve. The exhaust valve remains closed preventing any escape of air through the exhaust port. APPLYING: LOSS OF AIR IN THE SECONDARY CIRCUIT Should air be lost in the secondary circuit, the primary circuit will continue to function as described above under Normal Operation: Primary Circuit Portion. BALANCED: SECONDARY CIRCUIT When the air pressure on the secondary side of the relay piston approaches that being delivered on the primary side of the relay piston, the relay piston moves closing the secondary inlet valve and stopping further flow of air from the supply line through the valve. [. . . ] After a full application is released, the reading on the test gauges should fall off to zero promptly. It should be noted that the primary circuit delivery pressure will be about 2 PSI greater than the secondary circuit delivery pressure with both supply reservoirs at the same pressure. Important: A change in vehicle braking characteristics or a low pressure warning may indicate a malfunction in one or the other brake circuit, and although the vehicle air brake system may continue to function, the vehicle should not be operated until the necessary repairs have been made and both braking circuits, including the pneumatic and mechanical devices, are operating normally. Always check the vehicle brake system for proper operation after performing brake work and before returning the vehicle to service. 2. Remove the screw (9) securing the exhaust diaphragm (10) and washer (11) to the exhaust cover (12). Remove the four screws that secure the exhaust cover (12) to the lower body. Remove the Secondary inlet and exhaust valve assembly (13) from the lower body. Remove the four hex head cap screws securing the lower body to the upper body and separate the body halves. While applying thumb pressure to the primary piston, lift out and up on the three lock tabs of the primary piston retainer (15). Using a 3/8" wrench, hold the lock nut (16) on the threaded end of the stem (17) in the primary piston (2). Insert a screwdriver in the exhaust passage through the center of the valve and engage the slotted head of the stem. Remove lock nut (16), spring seat (18), stem spring (19), primary piston (2), and primary piston return spring (6). Caution: Before proceeding with the disassembly, refer to Figure 4 and note that the lock nut and stem are used to contain the primary piston return spring, stem spring and the relay piston spring. The combined force of these springs is approximately 50 pounds and care must be taken when removing the lock nut as the spring forces will be released. It is recommended that the primary piston and relay piston be manually or mechanically contained while the nut and stem are being removed. Using a screwdriver to restrain the stem, as in step nine, remove the lock nut (16), spring seat (18) and stem spring (19). Remove the relay piston (20), relay piston spring (21), primary piston and primary piston return spring (23) from the upper body. On valves manufactured after October 7, 1976, a small washer (24) will be found in the cavity in the lower side of the primary piston (22). Disassemble the primary piston by rotating the spring seat nut (25) counterclockwise. Coat the exhaust port and body of the brake valve with a soap solution. If the brake valve does not function as described above or leakage is excessive, it is recommended that it be replaced with a new or remanufactured unit, or repaired with genuine Bendix parts available at authorized Bendix parts outlets. REMOVAL 1. Identify and disconnect all supply and delivery lines at the brake valve. [. . . ] Following the vehicle manufacturer's recommended procedures, deactivate the electrical system in a manner that safely removes all electrical power from the vehicle. 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. must be of equivalent size, type and strength as original equipment and be designed specifically for such applications and systems. [. . . ]