TM-9-2815-220-24 Maintenance Manual for AVDS-1790-2CA AVDS-1790-DA and AVDS-1790-2DR Engines Download
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TM 9-2815-220-24 HELICAL-COIL INSERT REPLACEMENT 0029 00 THIS WORK PACKAGE COVERS: Removal, Cleaning, and Installation INITIAL SETUP: Tools: Extraction tool (see items 39-41 for size, WP 0176) General mechanic’s tool kit (item 121, WP 0176) Inserter tool (see items 66-70 for size, WP 0176) Expendable and Durable Items:: Lubricating oil (item 21, WP 0173) Cleaning solvent (item 8, WP 0173) Personnel Required Track Vehicle Repairer (1) 63H10 To permit higher stresses on studs and bolts that are set in aluminum castings, it is common practice to install inserts of a stronger metal into which the studs or bolts are threaded. Helical- coil and screw thread inserts are designated to perform this function. The AVDS-1790 family of engines incorporates helical-coil inserts in many locations as original equipment. If the hole that the original insert is installed in becomes oversize, a threaded insert may be used in its place to allow the original size fastener to be used. Helical-coil 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. Part or item numbers of tools, kits and inserts, in addition to working dimensions are included in appropriate procedural work packages. REMOVAL CAUTION Do not damage threads of tapped hole when using extraction tool. Remove inserts from end of tapped hole where the insert is closest. Threads in tapped hole can be damaged. 1. Remove insert (1). a. Place extraction tool (2) in insert (1). Tap top of extraction tool (2) lightly with hammer to "set" tool. b. Maintaining a steady downward pressure, turn tool (2) counter- clockwise. Remove insert (1). 2 1 WP 0029 00-1