NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 GENERAL MAINTENANCE, OVERHAUL, AND REPAIR PROCEDURES—Continued 0005 00 h. Bushings, Liners and Bushing-Type Bearings. The following general instructions apply to bushings, liners, and bushing-type bearings. (1) Replace all bushings and bearings listed in Mandatory Replacement Parts List (WP 0052 00). (2) Check all bushings, liners, and bushing-type bearings for secure fit in their respective casting or mating part and for the evidence of heating, which may be indicated by discoloration of bushing or bearing surface. (3) Inspect for wear, burrs, nicks, or out-of-round condition. (4) Check for dirt in lubrication holes or grooves. Holes and grooves must be clean and free from damage to insure proper lubrication. (5) Inspect thrust faces of bushing-type bearings for wear and by temporarily assembling mating parts and checking end play with a feeler gage inserted between the thrust faces. (6) Check for conformance to the applicable overhaul inspection procedures. i. Screw Thread Inserts. (1) Description. To permit higher stresses on studs and bolts that are set in aluminum castings, screw thread inserts of a stronger metal are installed into which the studs or bolts are threaded. The inserts are spiral steel coils having a right hand thread-shaped form on the inside and on the outside diameter of the coils. A bar or tang at the bottom end of the coil, which is engaged by an inserting tool, is used for threading the insert into the casting. Some inserts have a serrated tooth section at the top end of the coil to stake them in place in the castings. Other inserts have turns at the center of the coil in the form of a hexagon. This provides a locking effect when the stud or bolt is threaded into the insert. (2) Inspection. Inspect all screw thread inserts for secure fit in the casting and for galled or stripped threads. 6. Repair. a. General. Some engine parts and components may be repaired as outlined below. Any repair procedures that are peculiar to a specific part or component is covered in the section or paragraph relating to that item. After repair, clean all parts thoroughly to prevent metal chips from repair operations or abrasives used in repair operations, from entering the working parts of the engine. 0005 00-5 Change 1