TM 55-1930-209-14&P-21
(e) Align upper end of connecting rod with hole in reaming fixture.
(f) Install rear guide bushing on reamer, then slide reamer and bushing into fixture.
(g) Turn reamer in a clockwise direction only, when reaming or withdrawing reamer. For best results,
use only moderate pressure on reamer.
(h) Remove reamer and connecting rod from fixture, blow out chips and measure inside diameter of
bushings. Inside diameter of bushings must be 1.3760 to 1.3765 inch. Pin to bushing clearance should be .0010 to
.0019 inch. Piston pin diameter will be 1.3745 to 1.3750 inch.
(13)
Refer to Table 1-1 for dimensions and measure connecting rod bearings for excessive wear. Visually
inspect bearings for excessive wear to determine if used bearings are satisfactory for further service. Upper bearings,
which carry load will normally show signs of distress before lower bearings do.
(14)
Refer to Table 1-1 for dimensions and measure thickness of bearing 90° from parting line using a
micrometer with a ball attachment.
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Piston and connecting rod, reassembly and installation
a.
Reassembly
(1)
Apply clean engine oil to piston pin and bushing and rest piston in a fixture.
CAUTION
Do not drive too hard on pin retainer or pin bushing may be moved inward and result in
reduced pin clearance.
(2)
Install one piston pin retainer in piston. Strike installation tool just hard enough to deflect retainer and seat
it evenly.
(3)
Slide piston pin into piston and connecting rod and install second piston pin retainer as in step (2) above.
NOTE
Piston pin will slip readily into position without force and must float freely after
installation.
(4)
Check piston pin retainers for proper sealing as follows:
(a) Place suction cup of leak detector over retainer.
(b) Hand pump fixture until gage reads 10 inches.
(c) A drop in gage reading indicates air leakage.
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