replacement of cure-date items and parts listed under
stop plate, as shown in figure 14-24. Reassembly is
essentially the reverse order of disassembly. Steps that
Spares and Replacement Parts Data in the
require quality assurance verification in the MIMs are
"Intermediate Maintenance" section of the MIM.
identified by the letters "QA" after the applicable
Figure 14-24 shows an exploded view of the
steps. When QA is assigned to a step or a heading that
selector valve. Observe the arrangement in which the
is immediately followed by substeps, the inspection is
machine screws are lockwired to aid in reassembly.
applicable to all substeps. The four machine screws
Disassemble the valve and clean all parts with P-D-680
that hold the selector valve assembly together must be
cleaning solvent. Dry all parts thoroughly, using
tightened and properly lockwired.
low-pressure, moisture-free, compressed air or a
NOTE: In some MIMs, the steps in a procedure
lint-free, clean cloth. Inspect all parts for scratches,
that require a QA inspection are underlined or
cracks, scoring, burrs, nicks, excessive wear, and
distortion. If any part other than those listed in the
Spare and Repair Parts Data is faulty, the component
Bench test the repaired valve to verify its
must be tagged to show the fault and forwarded to the
ready-for-issue (RFI) condition. The hydraulic fluid
next higher level of maintenance.
used to test the valve must be continuously filtered by a
3-micron absolute, nonbypass filter upstream of the
Replace all sealing devices and worn or damaged
valve. Allow the test stand fluid to reach an operating
parts. Apply a light coating of hydraulic fluid on all
temperature of 70° to 110°F before the testing begins.
O-rings, backup rings, seals, and wear surfaces before
reassembly. Note the proper assembly of the seal,
The valve must pass a proof test, static pressure test,
O-ring and backup ring, and the proper assembly of the
actuation (operational) test, and leakage tests. During
Shear plate assembly
Figure 14-24.--Brake selector valve--exploded view.