NUMBER: 5–50–01 S.M. REF.: 1.23.3 ENGINE: 50 DATE: May 2001 SUBJECT: IMPROVED THRUST PLATE PERIMETER SEAL INTRODUCTION Detroit Diesel has improved the perimeter seal used in the perimeter groove of the camshaft thrust plate. This change went into effect in August 15, 2000. DETAILS AND REASON Detroit Diesel has determined that an improved thrust plate perimeter seal (P/N 23528491) should be used in the perimeter groove of the camshaft thrust plate. The new seal provides greater reliability and less susceptibility to twisting during installation. In addition, the ribbed sides on the seal provide a means to check for proper positioning. The improved thrust plate perimeter seal is installed in the thrust plate groove as follows: 1. After passing a new perimeter seal between the thrust plate and cylinder head, carefully install it in the thrust plate groove with the ribbed edges against the sides of the groove and the beveled edge facing out. NOTE: The former thrust plate perimeter seal was redesigned to provide greater reliability and less susceptibility to twisting during installation. See Figure 1 for design configuration. Figure 1 Thrust Plate Perimeter Seal NOTICE: Failure to properly seat the perimeter seal in the thrust plate groove will result in seal damage. If the seal twists at initial installation or when pushing in the thrust plate, the seal can be cut and damage will result. Any seal damage can result in seal leakage during engine operation. 2. To check the thrust plate perimeter seal’s installation, rotate the thrust plate by hand and feel the seal to ensure it is fully seated in the thrust plate groove. If any ribs are felt on the outside edge, the seal is twisted and must be adjusted. NOTE: When pushing the thrust plate and seal into the gear case, the seal may appear to twist. Do not be concerned because it is only rolling a little. As long as the seal was not twisted when initially installed, the seal will straighten itself out because its profile is designed to resist rolling. 3. Apply Super Lube® to the inside bore of the gear case housing and not the seal. ADDITIONAL SERVICE INFORMATION Additional service information is available in the Detroit Diesel Series 50 Service Manual, 6SE50. The next revision to this manual will include the revised information. As a convenience to holders of the Series 50 Service Manual, information in service manual format is attached. The page(s) may be inserted into the manual. NOTE: Manual insert pages are numbered for insertion into the current Series 50 Service Manual dated June 2000. Service manuals are available from authorized Detroit Diesel distributors. If this bulletin was obtained from the Internet, service manual page(s) are available by returning to the screen “SIB Index”, selecting attachment pages, and printing the page(s). Detroit Diesel®, DDC®, Series 50® and the spinning arrows design are registered trademarks of Detroit Diesel Corporation. Super Lube® is a registered trademark of Synco Chemical Corporation. © Copyright 2001 Detroit Diesel Corporation. All rights reserved. Printed in U.S.A.