TM 5-4310-356-14
Section III. REPAIR AND OVERHAUL INSTRUCTIONS
AIR COMPRESSOR ASSEMBLY AND ELECTRIC MOTOR
Each rod half is matched when manufactured. Remove
5-4. Pistons, Piston Rings, Connecting Rods, and
oil dipper (15) only if replacement is required.
Cylinder Block.
CAUTION
Mark the connecting rod from
a. Removal and Disassembly.
which the caps were removed,
and reassemble caps on the same
rod.
Do not intermix the
described in paragraph 4-14a.
connecting rods and caps.
(2) Refer to figure 5-7 and remove intake
muffler assembly (12), by loosening set screw (11). To
disassemble the intake muffler follow the sequence of
and 18) by removing piston pin retaining rings (11) and
the reference numbers shown on the exploded view.
piston pins (12 and 17).
NOTE
(8) by loosening nut (6) and bolt (7). Pull from
Do not remove piston pin
crankshaft and remove key (9). Removing the flywheel
bearings (14) from rods unless
at this point facilitates the disassembly of tubes and
replacement is required.
fittings.
b. Cleaning, Inspection and Repair.
(4) Refer to figure 5-7 and disconnect and
remove all tubing and fittings. Follow any logical
(1) Clean all parts with an approved cleaning
sequence in removing tubes and fittings. Take care in
solvent and dry thoroughly.
removing intercooler tubes so as not to damage cooling
(2) Inspect the cylinder block for broken
fins.
cooling fins and cracks. Inspect the cylinder bore for
wear, scoring, pitting or other damage. Replace the
block if defective. Refer to Table 5-2 for allowable wear
tolerances.
(6) Remove intake valves (32 and 34) and
exhaust valves (33 and 35) from cylinder head valve
(3) Measure the clearance of the piston pin to
cavities. If disassembly of valves is desired follow the
the piston pin bushing. Check for proper fit. Aline or
sequence of reference numbers shown in figure 5-8.
replace connecting rods, if necessary.
(4) Place the piston rings in the cylinder bore
CAUTION
with the piston ring square in the cylinder bore about 0.5
Keep the parts of each valve
inch (12.7 cm) from the top.
assembly together, and separate
from those of other valve
(5) If the ring gap is less than the specified
assemblies. If serviceable, these
width, file across butt ends of the rings to increase the
parts shall be installed together.
gap to the required tolerance. If the ring gap is greater
than required, replace the entire set of rings.
(6) Measure the ring groove in the piston for
and remove cylinder head (37) by pulling straight away
wear. Replace piston if necessary.
from crankcase. Do not cock or twist or use undue
c. Reassembly and Installation.
lateral force against cylinder to avoid damage to the
pistons and connecting rods. Remove gasket (38) and
discard.
bearings (14) into connecting rods (16) if previously
removed. If new piston pin bearings are to be installed,
(8) Access to connecting rod attaching bolts
and are not prefit, ream the bearings. Refer to Table 5-
(10, fig. 5-9) is provided from above after cylinder head
2 for recommended tolerances.
has been removed. Remove connecting rod bolts and
withdraw lower connecting rod segment (16) from
crankcase. Immediately tag lower cap segment to
identify it with the exact rod from which it was removed.
5-13
