User manual BENDIX DD-3-SD-3 SAFETY ACTUATORS

[. . . ] ® Bendix® DD-3TM & SD-3TM Safety Actuators SERVICE DIAPHRAGM AUXILIARY DIAPHRAGM PUSH PLATE & SHAFT LOCKING ASSY. PISTON O-RING LOCKPORT DRAIN SLOT LOCKING PISTON CAP O-RING ROLLER SPRING FRONT SEAL EMERGENCY PORT SERVICE PORT SEPARATOR RETURN SPRING REAR SEAL ROLLERS (8) SPLASH PLATE EXHAUST DIAPHRAGM GASKET FIGURE 1 - DD-3TM SAFETY ACTUATOR DRAIN SLOT SERVICE PORT LOCKING PORT FIGURE 2 - SD-3TM SAFETY ACTUATOR 1 SD-02-4600 DESCRIPTION The DD-3TM and SD-3TM are air operated actuators with a mechanical push shaft lock. 1) is a double diaphragm device which provides braking for service, emergency, and parking. It is available in two sizes: type 24 and type 30. [. . . ] EVERY 3 MONTHS, 900 OPERATING HOURS, OR 25, 000 MILES When grease fitting is provided, grease with Lubriplate "Aero" lubricant. EVERY 12 MONTHS, 3600 OPERATING HOURS, OR 100, 000 MILES 3 5. Spread clamping rings slightly, just enough to slip rings off plates, It may be necessary to use a soft mallet to break the clamping rings loose. If clamping rings are to be reused, caution should be taken so they are not distorted. Remove auxiliary pressure plate, auxiliary diaphragm, service pressure plate, service diaphragm (with separator, if present). On SD-3TM actuators, pressure plate and service diaphragm only. Place non-pressure plate assembly on a smooth surface with the push plate down. Connect an air supply (shop air) line to the locking port. Push down on the actuator non-pressure plate; maintaining air pressure at the locking port. As the shaft is unlocked (released), ease the non-pressure plate back and remove the push plate and shaft assembly with push rod and return spring. While holding cap assembly down against roller spring tension, completely remove four (4) machine screws, release cap assembly, and remove. Remove retainer from cap by turning in clockwise direction until tabs of retainer line up with slots in cap. Remove roller spring (G), spring seat washer, and eight (8) rollers (F) (Fig. Remove collar (E), piston (C), and piston o-ring. NOTE: If necessary, apply air cautiously at the lock port to assist in removal of the above parts. Remove rear retaining spring by dislodging from groove of plate and remove rear seal. Inspect bearing in shaft bore on non-pressure plate, and remove only if it shows signs of wear and is to be replaced. The push rod should not be removed from the shaft unless it is damaged and requires replacement. To remove rod, place a heavy washer over the rod against the shaft; position a spacer (short length of pipe) and a second washer over the rod (and on top of the spacer). Install yoke lock nut(s) and turn down with a long-handled wrench, pulling the push rod from the shaft. Remove exhaust check valve from non-pressure plate. The studs in the non-pressure plate may be removed and replaced if necessary. [. . . ] Should leakage be detected at the clamping rings in either of the above tests, the clamping ring nuts should be tightened evenly but only enough to stop leakage. If the safety actuator does not function as described or leakage is excessive, it is recommended that it be returned to the nearest Bendix authorized distributor for a factory reconditioned actuator under the repair exchange plan. If this is not possible, the actuator can be repaired with genuine Bendix parts. OPERATING AND LEAKAGE CHECKS OPERATING - DD-3TM ACTUATOR With the actuator in the released position, make several brake applications and note that actuators apply and release properly. Operate parking control valve and observe that actuators apply. [. . . ]