TM-9-2815-220-34 Direct Support Manual for AVDS-1790-2C and AVDS-1790-2D Engines Download

TM 9-2815-220-34 (4) Inspect all tapped openings for stripped or damaged I hrcads. (5) Check all castings for conformance to applicnble rcpnir standards. e. Ball a11d Needle Beari11gs. Refer to TM 9-214 for inspection of anti-friction bearings. Check all bearings for conformance lo the applicable repair standards. f. Studs. Inspect all studs for damaged or stripped threads, hcnt. or loose condition, or for any signs of . stret.ching. g. Dowel Pins. Inspect dowel pins for looseness or damage. Mark lꝏse pins for repair. h. G<>ars and Shafts. NOTE There are no established wear limits for gear teeth and splines. Good judgment is required to determine need for replacement. (1) Inspect all gears and shafts for cracks using a magnifying glass (five power magnification minimum) and a strong light. (2) Inspect all gear teeth and splines for wear, sharp fins, burs, and galled or pitted surfaces. (3) Inspect shaft and gear hub splines· for damage, wear, and fit with splines on mating parts. Mating :plines must match without binding or looseness. (4) Check all gears and shafts for conformance to the applicable repair standards. i. Bushings, Liners, and Busliins·type Bearinss. (1) Check all bushings, liners, and bushing-type bearings for secure fit in their respective casting or mating part, and for evidence of heating, which may be indicated by discoloration of bushing or bearing surface. (2) Inspect for wear, burs, nicks or out-of-round condition . (3) Check for dirt in lubrication holes or grꝏves. Holes and grꝏves must be clean and free from damage to insure proper lubrication. (4) Inspect thrust faces of bushing-type bearings for wear and by temporarily assembling mating parts and checking end play with a feeler gage inserted be- tween the thrust faces. (5) Check for conformance to the applicable repair standards. j. Oil Sea ls. Generally, metal encased oil seals are long-life parts and do not have to be replaced during repair if inspection indicates seals are in good con- dition. (1) Inspect for damage to the thin feather edge of oil seal which contacts rotating part. (2) Inspect sealing feather edge for softness and pliability. (3) Replace damaged or questionable seals. 3-60 Change 3 k. Helical-Coil and Scr.ew-Tliread Inserts (1) Descriptio11. To permit higher stresses on studs and bolts which 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 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 tꝏl, is used for threading the insert into the casting. Some inserts have a serrated tꝏth 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 lking effect when the stud or bolt is threaded into the insert. (2) lnspectio11. Inspect all helical-coil and screw thread inserts for secure fit in the casting and for galled or stripped threads. I. Painted Pa. Straighten parts as necessary and check for broken welds, lꝏse rivets or weld nuts. If parts are cracked or torn, they must be repaired or replaced. Check shroud seals for hardness, tears, or other damage. Mark damaged seals for replacement if the part is otherwise serviceable. 3-38. Repair a. General. Most engine parts and components may be repaired as outlined below. After repair, clean all parts thoroughly to prevent metal chips from repair operations, or abrasives used in repair operations, from entering working parts of engine. b. General Repair of Castings. { 1) Replace all castings when cracks have penetrated high stress areas such as fillets or web· bing. (2) Replace all castings which do not con- form to tolerances specified in the appropriate repair standards tabl e. (3) Replace alJ castings on wllich machined surfaced are burred or nicked to the point of impairing subsequent assembly or operation. Re- pafr minor damage to mached surfaces with a fine mill file or crocus cloth dipped in dy-cleaning solvent (P-D-680, Type H). I ( 4) Replace all castings having flanges which are severely warped and cannot be repaired  provide a proper seating surface with its mating part. Repair minor warpage of mounting flanges and mounting pads by working surface ac ross a sheet of cro cus cloth held tightly on a surface plate or similar flat surface. ( 5) Repair damaged pipe threads in tapped holes with a used tap. ) ) )