Document 2Kp0Xn4BO3k2ggL9MLoR1V8g

BULLETIN NOVEMBER 24, 1976 underi\0. Q89 brakes FOR BRANCHES. DISTRIBUTORS AND CUSTOMERS. CHASSIS AFFECTED ALLENTOWN0^HAYWARD0^OAKVILLE BRAKE improvements (All with Stopmaster II 15 x 7 Wedge Brakes) PURPOSE To advise of improved parts for the self-adjusting mechanis PLAINTIFF'S EXHIBIT MAC-71 RECOMMENDATION Install the new parts listed in bulletin when overhauling the brakes or if existing adjusters bottom out with a useable amount of lining left. INFORMATION Early production of Stopmaster II brake assemblies had a limited travel adjusting bolt. These brakes reach their maximum adjustment before the lining is worn to the rivet heads. A new adjusting bolt is used in current production brake assemblies that permits additional lining wear. This bolt does not have the retainer ring to serve as a stop, thereby allowing full length of the bolt for adjustment. A new actuator is required with this bolt. See Figure 1 for details of this change. PRINTED IN U S A . FULL LENGTH THREADS IN ACTUATOR RETAINER RING NOT USED SEAL ACTUATOR ADJUSTING BOLT -- CURRENT NON^URRENT FIGURE 1 ADJUSTING BOLT AND ACTUATOR ACTUATOR COUNTER BORED FOR RETAINER RING CLEARANCE RETAINER RING TO LIMIT BOLT TRAVEL Stopmaster II assemblies can be identified by the slotted adjusting pawl guide hole and keyed adjusting pawl as shown in Figure 2. Late production assemblies also have the designation 'STOPMASTER II" stamped on dust shield. SERVICE NOTE A special, longer adjusting bolt is available for service use to permit full lining wear with refinished drums. This bolt is 0.100 inch longer than the standard bolt and ib . ^signed for use with drums having a diameter greater than 15.060 inches but less than 15.120 inches. It is intended for use with regular service thickness linings and can be identified by a large letter 'S" on bolt shaft. (Continued Over) Service Operations, Allentown, Pa. U.S.A. CERCULATIO Service Manager Shop Foreman Night Foreman Night Foreman Inspector Leadman Inspector Leadman Inspector Leadman Unit Over haul Room Shop Office Mack New Parts: Component Current Production Service Part Non-Current Production Adjusting Bolt 8235-2297-L-3158 8235-2297-E-3307 8235-2297-D-2370 Actuator 8235-2297-N-3212 8235 -A2297 -N-3212 8235-2297 -F-2372 Retainer Ring 8235-1779-Z -650 Interchangeability of these parts is affected. The new adjusting bolt cannot be used with the old actuator. However, the old adjusting bolt can be used with the new actuator if the retainer ring is discarded. CAUTION Because of the greater adjustment range provided by the new adjusting bolt and actuator, it is possible for the linings to wear down to the rivets, resulting in brake drum damage. For this reason, lining wear should be checked periodically after installation of these parts and new linings installed when required. {// Q / FIGURE 2