TM 1-1520-238-23
6-198
6.40.
ENGINE NOSE GEARBOX PRELOAD SHIM REMOVAL/INSTALLATION (AVIM) – continued
b. Check preload shim for scratches, nicks,
gouges, burrs, and corrosion.
(1) Repair damaged areas measuring 0.030
INCH deep or less by blending. Use depth
gage.
CAUTION
Exercise extreme care and accuracy
when taking measurements to deter-
mine if removed preload shim is within
tolerance limitations. Correct thick-
ness of preload shim is critical to prop-
er operation of engine nose gearbox.
Do not reuse removed preload shim if
thickness does not fall within tolerance
limitations. Damage to engine nose
gearbox may result.
c. Determine if thickness of removed preload
shim is within tolerance.
(1) Measure and record thickness of removed
preload shim. Use caliper set.
(2) Measure depth from outer face of gearbox
housing (3) to outer race of installed duplex
bearing (4). Use depth gage.
(a) Record as dimension A.
(3) Measure height from flange mating surface
(5) to bottom surface (6) of retainer (7). Use
caliper set.
(a) Record as dimension B.
(4) Subtract dimension B from dimension A and
add 0.004 INCH to answer.
(a) Record as dimension C.
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M04-3812-2
A
B
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4
7
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