Good housekeeping and maintenance practices help eliminate problems caused by contamination. Be careful if you work on a hydraulic system in the open, especially under adverse weather conditions. Use caution if you work on hydraulic equipment near grinding, blasting, machining, or other contaminant-generating operations. Often, you cannot see harmful grit. Do not break into hydraulic systems unless absolutely necessary (this includes cannibalization). Use the proper tools for the job. Use only authorized hydraulic fluid, O-rings, lubricants, or filter elements. When dispensing hydraulic fluid, make sure you use an authorized fluid service unit. Check to make sure that the hydraulic fluid can is clean before it is installed. After use, dispose of all empty hydraulic fluid cans and used hydraulic fluid in accordance with Navy and local hazardous material (HAZMAT) instructions. Keep hydraulic fluid in a closed container at all times. Keep portable hydraulic test stand reservoirs above three-quarters full. Seal all hydraulic lines, tubing, hoses, fittings, and components with approved metal closures. You should not use plastic plugs or caps because they are possible contamination sources. Install quick-disconnect dust covers. Store unused caps and plugs in a clean container.

Remove exterior contaminants by using approved wiping cloths. Lint-free wiping cloths should be used on surfaces along the fluid path. If possible, have the replacement component on hand for immediate installation upon removal of defective component. Replace filters immediately after removal. If possible, fill the filter bowl with proper hydraulic fluid before you install it to minimize the induction of air into the system. Do not reset differential pressure indicators if the associated filter element is loaded and in need of replacement. When cleanable filter elements are removed from hydraulic systems, put them in individual polyethylene bags and forward them to the intermediate- or depot-level maintenance activity for cleaning. Do not clean cleanable filter elements by washing them in a container and blowing them out with shop air. Cleanable filter elements must be cleaned and tested according to applicable procedures before they are reused. Clean all connections, interconnect the pressure and return lines of the stand, and circulate the hydraulic fluid through the test stand filters before connecting portable hydraulic test stands to aircraft.

NOTE: Do not use chlorinated solvents to clean connectors. Use dry-cleaning solvent P-D-680 or filtered hydraulic fluid.

Store O-rings, tubing hoses, fittings, and com-ponents in clean packaging. Do not open or puncture individual packages of O-rings or backup rings until just before you use them. Do not use damaging the O-ring.

If packages of tubing, hoses, fittings, or components are opened when received or found opened, decontaminate their contents. Decontami-nate the system if you suspect it is contaminated (including water). Keep the working area where hydraulic components are repaired, serviced, or stored clean and free from moisture, metal chips, and other contaminants. Perform required periodic checks on equipment you use to service hydraulic systems. Use hydraulic fluid MIL-H-46170 in stationary hydraulic test stands.