Figure 4-27. Combination Bulkhead and Universal Fitting Assembly

TM 1-1500-204-23-2 Figure 4-27. Combination Bulkhead and Universal Fitting Assembly (7) Installation of Rosan Fluid Fitting will be installed in accordance with TM 43-0104. g. Flared Fittings. Flared fittings, like flareless (MS) fangs, come in many different shapes. The main difference between AN and MS fittings Is the manner in which the hydraulic tube fits to the fitting. The MS fitting has a counterbore In which the tubing Is inserted; the AN fitting has a 37 degree flared (beveled) face to which the tubing is fitted. This flared area of the fitting is the seating surface and must be maintained. Any bad flare on this sealing surface will show up as a hydraulic leak. (1) Identification. AN flared fittings can be identified by the part number, as described In table 4-9. (2) Types. See figure 4-28 for examples of flared fittings. (3) Use of old fittings in oxygen systems. In repairing oxygen systems, it is usually possible to use the old fittings. Fittings should be cleaned before they are installed. Refer to paragraph 4-2g (2) for cleaning procedure for oxygen fittings. (4) Repairing tubing fittings. See figure 4-29 for repairable and non-repairable defects of tubing fittings. Tubing fittings may be repaired provided 80 percent of seat remains after repair. The only marks allowed on seat surface are annular tool marks of 100 microinches root mean square maximum. Fittings that cannot be salvaged by this method should be rejected. Reworked aluminum alloy fittings should be anodized. Minor scratches are not cause for replacement If wrench damage to a hexagonal section of a fitting does not exceed one corner, it should be reworked with a fine file in such a manner as to leave no file marks. A maximum of one corner may be reworked provided 75 percent of reworked flange width is not damaged. Damaged threads should be inspected and repaired. NOTE All screw threads MIL-S-7742, that are within the pitch diameter tolerances of Class 2, after rework, are acceptable for further use. Deleted High pressure hose end fitting assemblies, 300 psi and swage-type fittings of any pressure range, should not be reworked. MIL-F-8789 states that MS28760 and MS28761 fittings should be used only once. Coupling nuts sometimes modified for use on hose end fitting assemblies are not Inter- changeable with AN8 18 nuts. All AN fittings that cannot be salvaged by this repair should be condemned. 4-4. Repair of Tubing Assembliles. Scratches or nicks no deeper than 1 percent of the wall thickness in aluminum alloy tubing may be repaired, if they are not in the heel of a bend. Replace lines with severe die marks, seams, or splits in the tube Any crack or deformity in a flare is also unacceptable and is cause for rejection. A dent of less than 20 percent of the tube diameter Is not objectionable, unless it is in the heel of a bend. Dents can be removed by drawing a bullet of the proper size through the tube by means of a length of cable. Change 1 4-25