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

NOTE Pipe plug threads in castings must be in good condition  prevent oil leakage. c. Ball and Needle Bearing$. ( 1) Replace all galled, pitted, or damaged bearings. ( 2) Replace alt bearings which do not conform to tolerances specified in the appropriate .repair standards table. ( 3) Refer to TM 9-214 for information on in- spection, care, and maintenance of anti-friction bearings. d. Stud$. Replace all bent or loose studs or studs showing evidence of stretching. Repair minor damage with a thread chaser. Replace all studs having stripped or damaged threads. Remove and replace studs as outlined in (1) and (2) below. ( 1) Stud identification. Stud identification tables appear in the repair sections of this chap- ter. Each table contains the appropriate in- formation regarding stud setting heights, number required and reference figures of stud iden- tification and location. ( 2) Removal. Using a stud extractor, back studs out slowly to avoid heating and possible seizure. When studs are broken off too short to use extracr, drill stud and extract with a suitable remover. Short studs may also be removed by welding a eiece of bar stock or a nut to stud and removing with a wrench. STUD STANDARD 0.3 0.7 OVERSIZE OVERSIZE COLOR CꝃE ONE REO BLUE MARK 0 Í É TA021526 Figure 3·141. Stomrd 011d mer1i&e 11ud identificotio11. ( S) Replacement. (a) Repair minor thread damage in tapped holes with a used 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 as shown in figure 3-141 to be sure TM 9·2815·220-34 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 S-141 are marked on the coarse thread end of stud. (d) Apply a small amount of OE engine oil or GAA grease to threads before installing stud. (e) Drive stud into tapped hole slowly to prevent heating. Drive to setting height given in appropriate table. ( When tapped holes in castings cannot be fitted with oversize studs, the holes in the castings can be fitted with helical-coil inserts (para S-39) and studs of the original size can then be installed. e. Dowel PiM. Replace loose dowel pins. If original dowel pin was only slightly loose, install new pin using sealing compound, Specification MIL-S-6478. 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 dowel pin in the bushing. f Painted Paru. Retouch or paint parts as necessary to produce an acceptable part. Retouch or repaint parts in their original color in ac- cordance with procedures contained in TM 0- 0139. g. Gears and Shafu. ( 1) Replace all cracked gears and shafts, and shafts that are bent or twisted. ( 2) Replace all gears and shafts which do not conform  tolerances specified in the repair stan- dards tables. ( 3) Replace all gears and shafts having worn, galled, nicked, bured, or pitted teeth and splines. Remove any sharp fins and burs from splines with crocus cloth dipped in dry-cleaning solvent (P-680, Type II). I ( 4) Replace all splined gears and shafts that are damaged  the point of impairing assembly or operation. Replace all gears and shafts having splines which do not match properly with mating splines. I•. Btuhing, Liner$, and Bu.Yhing-Type Bearing$, When bushings, liners, and bushing-type bearings are damaged or worn beyond specified limiʦ, generally the associated parts with which they are used must be replaced. Reference to ( 1) and ( 2), below, will be made in the repair section for the particular part when replacement of bushings, liners, and bushing-type bearings is required. ( 1) Removal. Drill out bearing retaining pins when used to secure bearings in castings or retaining cages when applicable. Change 3 3-61