NMWR-9-2815-220 Overhaul Manual for M60 M88 Engine AVDS-1790-2CA, AVDS-1790-2DA, AVDS-1790-2DR Download
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NMWR 9-2815-220 OIL PUMP ASSEMBLY OVERHAUL—Continued 0013 00 RECLAMATION – Continued 2. Pressure oil pump housing (part no. 1168395) and scavenge oil pump housing (part no. 116839461). Repair worn impeller bore surfaces by arc welding. Refer to Table 23 (OIP 11683971) and Table 20 (OIP 11683997). Welders to be qualified per AWS D17.1. (a) Thoroughly clean and degrease housing with cleaning compound degreaser. (b) With a suitable grinder, machine a relief approximately 3/32 in. (2.2860 mm) deep and 3/16 in. (4.8260 mm) high around the circumference at the bottom of the housing as shown in Figure 1. (c) Fabricate two flat fixture plates and drill to match the bolt patterns of the housing to be repaired. Attach the fixture plates to the housing using at least four thru-bolts (Figure 1). This will minimize distortion of the housing and serve as a heat sink during welding. The plate over the impeller bores should be open. (d) Using the gas tungsten arc welding process in accordance with AWS D17.1 and MIL-STD-372(2), weld the impeller surfaces as described below: (1) Deposit a stringer bead at the bottom of bore and up the side to the top. (2) Repeat the process, alternating sides, until impeller surfaces are completely renewed. Ensure the welds overlap sufficiently to allow for remachining to drawing tolerances. (e) Machine and polish impeller surfaces, using a suitable grinder, to drawing specifications (DWG 11683965 or 11683946). (f) Inspection. (1) Apply liquid penetrant and inspect welded area per MIL-I-6866(2). (2) Acceptance criteria – No linear indications due to weld cracking, crater cracking, lack of fusion, etc. No porosity exceeding 1/8 in. (3.3020 mm) diameter for a single indication on the entire surface or more than three indications larger than 1/16 in. (1.5420 mm) diameter on the entire surface. Figure 1. Arc Welding Oil Pump Housing Impeller Surfaces. 0013 00-4 Change 1