zero pressure, open the test chamber door and disconnect and remove the test hoses. After you complete the pneumatic test, stop the operation of the test stand. Adjust the air pressure regulator for a zero reading on the regulated air pressure gauge. Shut off the air supply shutoff valve. Open the high-pressure air bleed valve. When the high-pressure air gauge indicates a zero reading, drain the water by means of the drain valve at the bottom of the chamber. Open the test chamber doors and disconnect the test hose. HOSE AND HOSE ASSEMBLY MAINTENANCE Learning Objective:    Recognize the mainte- nance procedures and practices associated with hose and hose assembly maintenance. Maintenance of hose and hose assemblies at the organizational level is limited to contamination control, preventive maintenance, removal, installation, or replacement. Proper maintenance practices can minimize the problems that might occur with regard to hose and hose assemblies. MAINTENANCE PRACTICES Do not use hose or hose assemblies as foot or hand holds. Do not lay hose or hose assemblies where they may be stepped on or run over by vehicles. Do not lay objects on hose or hose assemblies. Turn the swivel nut when loosening or tightening fittings. Hold the socket only to prevent the hose assembly from turning. Perform all necessary turnoff or shut- down procedures as outlined in the applicable maintenance instruction manuals (MIMs) or technical directives before removing any hose or hose assembly. Cover open ends of hose, hose assemblies, and fittings with protective closures. Make sure hose, hose assemblies, and connection points are cleaned before installing. PREVENTIVE MAINTENANCE Preventive maintenance consists of periodic inspection and correction of hose and hose assembly faults. In this process, you must check for leaks, wear, and deterioration. Special attention must be paid to hose or hose assemblies and clamps. Checking For Leaks Hose or hose assemblies should be replaced when leaks are found to be caused by damage to any part of a hose or hose assembly; poor seating or damaged threads of the socket or nipple assembly, which causes the fitting to leak; or excessive torque. If a leak appears in the swivel nut area, check that the swivel nut is properly torqued. If necessary, disconnect fitting and check for contamination or damage. If the leak persists after cleaning, and the swivel nut is properly torqued, replace the hose assembly. Checking For Wear and Deterioration Check hose and hose assemblies for signs of wear and deterioration. Replace any hose or hose assembly when a chafe guard appears worn or shows signs of cracking; when a firesleeve is worn through, torn, cut, or oil soaked; when hose or hose assembly has weather protective coatings or sleevings that are worn, cracked, or torn, thus exposing the hose or hose assemblies to corrosion. Checking Hose or Hose Assembly Installations Check hose or hose assembly installations carefully. Proper routing and clamping in accordance with applicable MIM is mandatory. If retaining wires on swivel nuts are backed out, replace the hose assembly. Look for kinks or twists. Observe lay line, if possible. A kinked hose or hose assembly must be replaced. A twisted hose or hose assembly may be relieved by loosening clamps and swivel nuts, and then straightening the hose by hand. Retorque the swivel nuts and tighten the clamps. A preformed hose, or hose assembly, may have a smaller bend radius. Do not attempt to straighten preformed hose or hose assemblies. Excessive bends or signs of chafing may be due to loose, oversize, or worn clamps. Replace oversized or worn clamps, and tighten the clamp without squeezing the hose. Checking Clamps You should check the clamps to make sure they are the correct type and size, that the position of the hose is correct within the clamp, and that the cushion material is positioned correctly. Reposition hose and clamps as needed. Cushion material should NOT lodge NOT between end tabs of a closed clamp. Do use clamps with fuel-resistant cushioning 5-23