User manual BENDIX SR-2 TRAILER SPRING BRAKE VALVE

[. . . ] Air passing through the service reservoir check 1 SD-03-4510 valve flows out the service reservoir port and then opens the spring brake reservoir check valve, allowing air to fill the spring brake reservoir. As air is filling the spring brake reservoir, it also flows by the open control inlet and out the delivery ports of the SR-2TM valve into the spring brake emergency ports releasing the spring brakes. SERVICE RESERVOIR CHECK VALVE SPRING BRAKE RESERVOIR CHECK VALVE SPRING BRAKE RESERVOIR CONTROL INLET & EXHAUST VALVE PRESS. PROTECTION INLET VALVE CONTROL PISTON SERVICE RESERVOIR PARK APPLICATION (Fig. 3) To park the trailer, either the trailer supply valve or the parking control valve, which are located in the cab, are actuated and the trailer supply line is exhausted. [. . . ] Shut off the engine leaving the ignition on and open the drain cock on the trailer service reservoir. The tractor air system should bleed down to approximately 45 psi with low pressure indication occurring at 60 psi. There should be no noticeable drop in pressure in the spring brake reservoir, and the trailer service reservoir test gauge should read zero psi. Allow one minute for the air pressure in the service reservoir to stabilize after obtaining a zero psi reading on the test gauge. The trailer spring brakes should remain released. Soap the trailer service reservoir drain cock and the exhaust port of the SR-2TM valve checking for leaks. A 1" bubble in 3 seconds is permissible. Leaving tractor air system pressure at approximately 45 psi, place the trailer supply valve in the exhaust position. After making sure the trailer spring brakes are applied, place the trailer supply valve in the charge position and the spring brakes should release. The trailer supply valve and possibly the parking control valve may have to be held in. NOTE: If the system functions as described, close the service reservoir drain cock as a final step in completing these tests. If the SR-2TM spring brake valve does not function as described above or leakage is excessive, repair the valve or replace it with a genuine Bendix service replacement valve. 3. NOTE: Do not attempt to remove the retaining ring and stem from the piston. REMOVAL AND DISASSEMBLY OF THE CONTROL PISTON (Reference Fig. Note and mark the position of the control piston cover (12) on the valve body. Remove the four 1/4" - 20 hex head cap screws (13) and lock washers which retain the cover to the body. Remove the cover, control piston assembly (14), and spring (3) from the valve body. From the control piston remove the three o-rings. Remove the reservoir port fitting (15) from the valve body. From the reservoir port fitting remove the o-ring (7). Remove the inlet valve spring (6) and inlet and exhaust valve (5). If so equipped, (Figure 1) remove the screw (19), washer (20) and diaphragm (11) from the exhaust port. [. . . ] 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. 8. Use only genuine Bendix® replacement parts, components and kits. Replacement hardware, tubing, hose, fittings, etc. [. . . ]