Hose assemblies.

Figure 4-48. Medium-Pressure Teflon Hose Assembly Procedure (Sheet 1 of 3)

TM-1-1500-204-23-2 General Aircraft Maintenance (Pneudraulics Maintenance and Practices) Volume 2 Manual
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TM 1-1500-204-23-2 (b) Hose assemblies. Flush or dip hose assemblies in cleaning fluid and brush, if necessary, to dislodge deposits. CAUTION Do not wire-brush dry tube surfaces. Failure to comply will result in destruction of the hose assembly. (c) Component parts. Thoroughly clean all component parts by dipping and brushing where necessary in MIL-D-16791 synthetic detergents only. (d) Cleaning hose assemblies after proof test. Flush or dip hose assemblies in cleaning fluid and drain. (10) Assembly procedures. The following steps shall be followed when fabricating hose assemblies from new or salvaged components (see figure 4-48). (a) Tools required. Use common hand tools, i.e., wrench, hacksaw, protractor, vise and hydraulic test stand. WARNING Hose assemblies conforming to MIL-H25579 and hose assemblies conforming to MIL-H-38360 use different hose and fittings. DO NOT interchange components between assemblies. Improper combinations of hose and fittings lead to life endangering failures. CAUTION End fittings shall not be installed on used aircraft hose MIL-H-27267 and/or MIL-H25579. Failure to comply may result In compromise of the integrity of the hose assembly. NOTE Assembly mandrels are not needed for hand assembly of fittings. (b) Hose length. Determine hose length by subtracting cutoff factor (table 4-22) from desired hose assembly length. Cut hose squarely. To prevent a flareout of the wire end during the cutoff operation, (figure 4-48, detail A) a piece of masking tape can be wrapped around the hose at the point. After the hose is cut, and before proceeding with the assembly, the tape must be removed. (c) Install sockets. To facilitate assembly on sizes up to -8, place two sockets skirt-to-skirt in vise (figure 4-48, detail B) and work hose through sockets with a pushing, twisting motion. Insert neck down to facilitate assembly. (d) Size tube and flare braid. Place nipple in vise. Push hose onto the nipple to size tube ID and to aid in separating the wire braid from the tube (figure 4-48, detail B). Remove hose from the nipple (e) Install sleeve. Carefully insert sleeve between braid and tube OD using caution that no wires are trapped between the sleeve and tube OD. Complete positioning by pushing end of sleeve against flat surface until tube bottoms against shoulder sleeve ID (figure 4-48 detail C). Visually inspect to see that tube end is bottomed against sleeve shoulder and that no wires are trapped under sleeve. (f) Sizing tube to sleeve. Size tube to sleeve by pushing nose over the nipple until the sleeve bottoms against the nipple chamber. Remove and recheck to be certain that the sleeve is still properly positioned Again push hose over the nipple and bottom sleeve against the nipple chamfer. NOTE No lubrication is needed, as components are permanently dryfilm lubricated. (g) Engage socket and tighten Slide socket forward and engage threads by hand. Remove assembly from vise and regrip by socket. Using a wrench on nipple hex, tighten to a gap of 1/32 inch nominal (gap may vary from 0.025 to 0.045 inch)(figure 4-48, details D and E). 4-60

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