When you install hose or hose assemblies, it is important that you follow certain practices or procedures to prevent premature failure of hose or hose assembly or possible injury. Before you begin actual installation procedures, there are guidelines you should remember about installing hose or hose assemblies. The replacement hose or hose assembly must be a duplicate of the one removed in length, outside diameter, material, type, contour, and associated markings.

Only fluid conforming to MIL-H-5606, MIL-H-83282, or MIL-H-81019 is to be used on hydraulic or pneumatic hose installations. Do not use oil of any type on self-sealing hose as an aid to installation. Compatible oil, approved for the purpose, may be used on all other types of fuel, oil, and coolant hose installations.

When you install or handle hose or hose assemblies, you can sustain injuries to your hands or damage to the hose if it is kinked. You should take care to prevent situations where injuries or kinking can occur. A hose that is bent to a smaller radius than specified might cause kinking. See table 5-8. A preformed hose assembly, or one that has become set-to-shape of its operating position, is straightened or handled without a protective restraint. A hose or hose assembly that is twisted during handling, removal, or installation can easily cause kinking.

Check hose or hose assembly before installing it to make sure that identification bands and protective closures are present as required after proof pressure testing. Inspect hose for proper type and size, and for aging (signs of deterioration such as cracks, dis-coloration, hardening, weather checking, or fungus). Check the braid for two or more broken wires per plait, or more than six broken wires per linear foot. Inspect for broken wires where kinking is suspected. Evidence of internal restriction of tube due to collapse, kinking, wire-braid puncture, or other damage can be found by using one of the following methods of inspection: For straight hose assembly, insert a light at one end and visually inspect from the opposite end. For elbow fitting on both ends (practical for larger sizes only), insert flexible

Table 5-8.Hose Minimum Bend Data

Figure 5-20.Hose twist. 

inspection light into one end and visually inspect from the opposite end using a small, angled, dental-type mirror. Inspect for any separation of covers or braids from inner tube, or from adjacent covers or braids. Look for flaring or fraying of braid. Look for blisters, bubbles, or bulging. Inspect for corrosion. A hose that has carbon steel wire braid is subject to corrosion, which may be detected as brownish rust coloration penetrating the outer braid.

Inspect end fittings for proper type and size, corrosion and cleanliness, nicks, scratches, or other damage to the finish that affects corrosion resistance. Look for damage to threaded areas, damage to cone-seat sealing surfaces damage to flange fittings, warping of flange, and for nicks or scratches on the sealing surface or gasket.