TB-9-2300-403-45 Technical Bulletin for Aluminum Oil Cooler Repair 6V53 8V71 AVDS-1790 Engines Download
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* TB 9-2300-403-45 DEPARTMENT OF THE ARMY TECHNICAL BULLETIN CONTINENTAL MODELS AV-1790 AND AO-895 AND GMC MODELS 6V53/6V53T AND 8V71T SERIES ENGINES: REPAIR OF ALUMINUM OIL COOLERS Headquarters, Department of the Army, Washington, D. C., 15 March 1971 1. Purpose. This bulletin provides general support, depot, and contractor maintenance personnel with instructions for repair of aluminum oil coolers by welding or brazing. 2. Scope. This bulletin applies to all GS, depot, and contractor repair of Continental Model AV-1790 and AO-895 and GMC 6V53/6V53T and 8V71T engines. 3. Equipment required. a. Arc welding machine for inert gas shielded tungsten arc (Heliarc, Argon- arc) or inert gas shielded metal arc consuming electrode process. b. Class 4043 electrode, conforming to specifica- tion QQ-R-556A or MIL-E-16053. c. ALCOA No. 33 torch brazing flux or equivalent. d. ALCOA No. 718 or 716 brazing alloy or equiva- lent, 1/16 and l/8-inch diameter. 4. Repair Procedure. a. Degrease coolers, using vapor or liquid solvents. Dry with compressed air. WARNING Degrease vapors may produce phosgene gas. Do not place coolers into alkali strip tanks. b. Prepare surface by removing all foreign matter from area to be welded by use of stainless steel wire brush, drill, burring tool, approved chemical proc- ess, or steam cleaning. c. Preparation of cracks, fractures, and areas having metal missing: (1) Use dye method to determine length of crack, if not visible. (2) Drill 3/16-inch stop holes at ends of the crack or fracture. (3) Mill or grind out cracks to provide a “V” aperture. *This Bulletin supersedes TB 9-288, 10 November 1959. d. Housing welding procedure. CAUTION Use extreme care in welding aluminum cool- ers to prevent damage to fins and tubes. Refer to TM 9-237 for preliminary instruc- tions on welding of aluminum. NOTE An interpass temperature of 250° F to 395° F, measured two inches from the weld, will be maintained until the joint is completely welded. (1) When preheat temperature of 350° F plus or minus 35 F has been reached, position housing in the most advantageous welding position. Cover all but the area to be repaired with asbestos blankets to maintain heat. (2) Weld the milled groove, assuring a good root weld; then, apply fillet welds until groove is filled and closed. (3) Remove blankets and allow to cool to room temperature. e. Machine the repaired surfaces back to original configuration. Repaired bolt holes must be proper- ly located, drilled, and threaded to original size and thread pitch. f. Replacement of Header Tube: (1) Clean in accordance with a above. (2) Plug all parts to prevent entrance of con- taminants. (3) Saw-cut each end of header tank. (4) Saw-cut each end of tube for removal. (5) Remove remainder of tube by reaming. (6) Saw-cut one end, as shown in Figure 1, to 1