should   change   the   defective   pumps,   check   filter elements,  and  decontaminate  the  system  as  required. Check the applicable MIM for corrective action to be taken  regarding  decontamination  of  the  system.  If this action is not taken, the complete system could be contaminated.  Hydraulic  systems  and  components are  serviced  by  using  approved  fluid  dispensing equipment only. Unfiltered  hydraulic  fluid  should NEVER  be  introduced  into  systems  or  components. All portable hydraulic test stands must receive the required periodic maintenance checks. Make certain that each unit is approved, and the applicable MIM is readily accessible and up to date. When the portable hydraulic  test  stand  is  not  in  use,  it  should  be protected  against  contaminants  such  as  dust  and water.  You  should  ensure  that  correct  hoses  are  used on each stand, and that they are approved for the type of  fluid  being  used.  Properly  cap  hoses  when  they  are not being used. Hoses must be serialized and must remain  with  the  equipment.  Make  sure  the  hoses  are coiled, kept free of kinks, and properly stowed. Make sure they are in satisfactory condition and are checked periodically.  Replace  any  hose  that  exhibits  fluid seepage from the outer cover or separation between the inner tube and the outer cover. Portable hydraulic test  stands  that  show  indications  of  contamination  or that have loaded (clogged) filters are removed from service immediately and returned to the supporting activity  for  maintenance. Use  only  approved  lubricants  for  O-ring  seals; incorrect  lubricants  will  contaminate  a  system.  Many lubricants  look  alike,  but  few  are  compatible  with hydraulic  fluids. The  only  approved  O-ring  seal lubricants  are  hydraulic  fluid  MIL-H-5606,  hydraulic fluid MIL-H-83282, hydraulic fluid MIL-H-46170, or a thin film of grease, MIL-G-81322. MAINTENANCE  PRACTICES 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  used   or unidentifiable  O-rings.  Replace  seals  or  backup  rings with new items when they have been disturbed. Use the correct O-ring installation tool when you install O-rings over threaded fittings to prevent threads from damaging  the  O-ring. 4-3