User manual BENDIX SR-1 SPRING BRAKE VALVE

[. . . ] This air remains under piston A as system pressure builds. 1 reservoir pressure below approximately 55 P. S. I. the spring above piston A forces it into contact with inlet and exhaust valve A causing the exhaust to seal and the inlet to open. With air system pressure above approximately 55 P. S. I. [. . . ] The single check valve in the SR-1TM valve assists this exhaust of air pressure by allowing the air below piston B to flow back out the open exhaust of the park control valve. When air pressure below piston B has dropped sufficiently, piston B moves down, opening the inlet of valve B and providing an additional exhaust passage for air exhausting through the SR-1TM valve from the spring brakes. 1. Place parking control valve in the "park" position. Observe that the spring brake actuators apply promptly. In the delivery port of the valve install a test gauge known to be accurate. Place the parking control valve in the "release" position. Observe that the spring brake actuators release fully. With the parking control valve in the "release" position, note the gauge pressure reading. (Check the vehicle manual for the correct spring brake actuator hold-off pressure. ) If the pressure reading is incorrect, the valve must be repaired or replaced. Place the parking control valve in the "park" position, the gauge reading should drop to zero promptly. A slow release of pressure may indicate faulty operation of the single check valve (within the modulating valve. ) 4. Place the parking control valve in the "release" position. Locate the number one service reservoir and drain it completely. Apply the foot brake valve several times and note that the pressure reading on the gauge decreases each time the foot brake valve is applied. After several applications, pressure on the gauge will drop to the point where release of the spring brake actuators will no longer occur. PREVENTIVE MAINTENANCE Important: Review the Bendix Warranty Policy before performing any intrusive maintenance procedures. A warranty may be voided if intrusive maintenance is performed during the warranty period. No two vehicles operate under identical conditions, as a result, maintenance intervals may vary. Experience is a valuable guide in determining the best maintenance interval for air brake system components. At a minimum, the SR-1TM valve should be inspected every 6 months or 1500 operating hours, whichever comes first, for proper operation. Should the SR-1TM valve not meet the elements of the operational tests noted in this document, further investigation and service of the valve may be required. LEAKAGE CHECK With the air system fully charged and the parking control valve in the "release" position, coat the exhaust port and around the valve corner with a soap solution. If the SR-1TM spring brake valve does not function as described above, or leakage is excessive, it is recommended that it be repaired or replaced with a genuine Bendix service replacement valve. 5 SERVICE CHECKS OPERATING CHECKS Block all wheels and hold by means other than vehicle brakes. Charge air brake system to governor cut-out pressure. Note: A maintenance kit for the SR-1TM spring brake valve is available from any authorized Bendix outlet. [. . . ] Remove the small piston (15) and the small and large o-rings (16). Remove piston o-rings (18) & (19). TESTING THE REBUILT SR-1TM SPRING BRAKE VALVE Test the rebuilt SR-1TM spring brake valve by performing the operation and leakage test outlined in the "Service Checks" section of this manual. CLEANING & INSPECTION Inspect all parts for excessive wear or deterioration. Inspect the valve seats for nicks or burrs. Use only genuine Bendix ® replacement parts, components and kits. [. . . ]