necessary, while component repair is in process.
Metallic wipers are formed in split rings for ease in
installation, and they are manufactured slightly
undersize to ensure a tight fit. One side of the
metallic wiper has a lip, which should face outward
upon installation. Metallic wipers must be inspected
for foreign matter and condition, and then installed by
sliding them over the piston shaft in the proper order,
as directed by the applicable MIM.
The felt wiper may be a continuous felt ring or a
length of felt with sufficient material to overlap its
ends. The felt wiper should be soft, clean, and well
saturated in hydraulic fluid during installation.
Protective Closures
Contamination is hazardous and expensive. To
protect hydraulic systems from contaminants, use
protective closures.
Two types of protective metal
closures are approved for sealing hydraulic
equipment. They are caps and plugs conforming to
appropriate military specifications. Guidelines for
selection and use of protective closures for hydraulic
equipment are as follows: Use caps and plugs of the
proper size and material. Never blank-off openings
with wooden plugs, paper, rags, tape, or other
unauthorized devices.
Use closures of metal
construction conforming to specifications listed in
table 2-2 for sealing hydraulic system equipment,
lines, tubes, accessories and components.
Table 2-2.—Protective Caps and Plugs
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