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
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
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.
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
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.