(9) Clean thoroughly, then inspect bearings for
signs of wear, or roughness. If bearings are worn, rough,
c. Cleaning, Inspection, and Repair.
or have other damage, replace the crankshaft assembly.
(1) Thoroughly clean the air heads by brushing
(10) Clean the unloader parts (fig.
or scraping lightly to remove accumulations of carbon
thoroughly, then inspect weights and pins for a free fit.
deposits, being careful not to damage gasket surfaces.
Be sure the gasket surface is free of all gasket particles.
(2) Use solvent Fed Spec P-D-680 and wash
(crankcase) on workbench. Fasten it down so it will not
away all accumulated oil. Be sure bore of cylinder is
tip over when weight is added by assembly.
clean, and that all gasket particles are removed from
surfaces to be gasketed.
Install new gaskets in all positions
(3) Wash pistons in P-D-680 solvent and
at reassembly, and a new oil seal in
remove all accumulated oil or carbon. Pay particular
the shaft end cover.
attention to the ring grooves. Be sure that oil return holes
(1) Install the crankshaft, complete (1, fig. 6-9)
in the oil control wiper ring grooves are open, and that
from frame end as follows:
grooves themselves are absolutely clean.
Remove the retaining ring from
(4) Inspect the cylinder bore for any signs of
scoring or scuffing. If the cylinder bore shows signs of
wear or scoring, as indicated by visible ridging-at the end
outer end bearing (near threaded end of shaft) then insert
of ring travel, it must be replaced (see (6) below).
shaft into the frame.
(5) Inspect the piston for signs of scoring, or for
(b) Guide threaded end through housing
any indication of cracked or broken lands. If these signs
until bearings reach their position, then tap gently with a
are found, replace the piston. If piston shows no signs of
soft hammer on the journal end of shaft until the empty
scoring, or cracked or broken lands, check the condition
retaining ring groove extends approximately 1/16 inch out
of ring grooves for signs of excessive wear. A tapered
of the housing.
ring groove would result in excessive clearance, and that
piston should be replaced.
(c) Insert retaining ring in its groove, then
tap the threaded end of shaft gently with a soft hammer,
until the retaining ring is tight against the housing.:
If new ring sets are to be installed
on pistons, and the old cylinder is
going to be re-used, the cylinder
Install oil seal with the sealing lip
walls must be de-glazed, or slightly
facing inside of the shaft end cover,
roughened to provide a proper
then press into position. If a vise is
seating-in surface for the new
used to press the seal, be sure
serrated jaws, if any, are covered to
protect seal from distortion.
(6) Cylinders that passed inspection in (4)
above, and are to be re-used, must be de-glazed as
(2) Install the shaft end oil seal (16) (see
Caution above) in housing(14).
(a) Use a No. 80 grit abrasive cloth
Protect lip of the seal from cutting
dampened in oleum spirits, or solvent Fed. Spec. P-D-
by the threads on end of crankshaft
680, and move it over the surface of the bore in a rotating
by wrapping a sheet of 0.003 inch
and reciprocating motion with a very light pressure.
brass shim stock around threads,
(b) After de-glazing, the cylinder wall
then slipping shaft end cover and
should be thoroughly cleaned with a hot soapy solution,
seal in position on frame.
using a good stiff bristle (not wire) brush.
(3) Place gasket (15) in position around shaft,
thoroughly with hot water then check cleanliness of the
then install shaft end cover and seal as described in
bore by wiping with a soft white paper cloth. If the paper
caution above. Secure cover with four steel washers (12)
shows more than a slight discoloring, the cylinder has not
and capscrews :(11). Tighten capscrews-to the torque
been properly cleaned.
value given for their size in table 1-1. Install connector
(10) and breather tube (9) in frame (17), then install
(7) Wash the oil reservoir portion of the frame,
nipple:(5), coupling (6), and plug (7).
being sure that accumulations of oil and sludge are
removed. Clean gasket surfaces for cylinders and end
(4) Install connector (25, fig.
covers. Be sure no particles of old gaskets remain on the
connecting rod (24). Check clearance between crankpin
bushing and connecting rod. It should be between 0.001
and 0.002 in. If clearance is 0.0025 in. replace bushing
(8) Clean the air valves in solvent Fed. Spec.
and connecting rod.
P-D680. Clean both valve and seat by brushing with a
stiff bristle (not wire) brush. Should it be necessary to
scrape carbon or sludge, do so lightly-with something soft,
like a square edge piece of hardwood. This will prevent
marring of valve or seating surface.