TM-9-2815-200-35 Maintenance Manual for AVDS-1790-2M AVDS-1790-2A and AVDS-1790-2AM Engines Download
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Figure 6-1. Standard and oversize stud identification. (3) Replacement. (a) When threads in tapped holes appear to be in good condition, clean threads with a tap. (b) When threads are stripped or damaged, or when stud was removed from an aluminum casting for loose fit, always replace stud with next larger oversize or in cases of complete thread pullout, drill out threaded holes, tap hole for thread insert, install insert and standard stud for repair. Markings and color code indicates whether stud is standard or oversize. Check marking and color code as shown in figure 6-1 to be sure replacement is of proper size. Note. When the threads on each end of the stud are a different size, the coarse thread end must enter the aluminum casting. (c) Studs available for replacement as shown in figure 6-1 are marked on the coarse thread end of stud. (d) Apply a small amount of mica-base antiseize compound, Military Specification MIL-T-22361, to threads before installing stud. (e) Drive stud into tapped hole slowly to prevent heating. Drive to setting height given in appropriate table. (f) When tapped holes in castings cannot be fitted with oversize studs, the holes in the castings can be fitted with helical-coil inserts (par. 6-5) and studs of the original size can then be installed. f. Dowel Pins. Replace loose dowel pins. If original dowel pin was only slightly loose, install new pin using sealing compound, Specification MIL-S-22473. In cases where the dowel pin hole is grossly out-of-round, it will be necessary to drill the hole oversize, fashion a bushing, and install a new pin in the bushing. g. Painted Parts. Retouch or paint parts as necessary to produce an acceptable part. Retouch or repaint parts in their original color in accordance with instructions contained in TM 9- 213. h. Gears and Shafts. (1) Replace all cracked gears and shafts, and shafts that are bent or twisted. (2) Replace all gears and shafts which do not conform to tolerances specified in the overhaul standards tables. (3) Replace all gears and shafts having worn, galled, nicked, burred, or pitted teeth and splines. Remove any sharp fins and burs from splines with crocus cloth dipped in dry-cleaning solvent or mineral spirits paint thinner. (4) Replace all splined gears and shafts that are damaged to the point of impairing assembly or operation. Replace all gears and shafts having splines which do not match properly with mating splines. i. Bushings, Liners, and Bushing-type Bearings. When bushings, litters, and bushing- type bearings are damaged or worn beyond specified limits, generally the associated parts with which they are used must be replaced. Reference to (1) and (2), below, will be made in the rebuild section for the particular part when replacement of bushings, liners, and bushing- type bearings is required. 6-7