SECTION XI
REPAIR AND OVERHAUL INSTRUCTIONS
AIR COMPRESSOR ASSEMBLY AND ELECTRIC MOTOR
COMPRESSOR REPAIR AND REPLACEMENT STANDARDS
Manufacturer's
Desired Clearance
Maximum allowable
dimensions and
wear amd clearance
tolerances in
inches
Min.
Max.
Min.
Max.
Cylinders
Bore low - pressure
4.6245
4.6255
0.004
Bore high - pressure
2.4995
2.5005
0.002
Out of round .-
0.001
Taper
0.001
Crankshaft
Journal rod) die-
1.370
1.3765
Taper
0.001
Out-of-round
0.005
End play
0.000
0.002
Pistons end Pins
Piston, low-pressure -
4.619
4.620
0.003
0.005
0.006
Piston, high-pressure-
2.4965
2.4975
0.0015
0.0035
0.003
Pin, low-pressure
2.125
2.135
0.0001
0.0005
Pin, high-pressure
2.125
2.135
0.0001
0.0005
Bearings, Connecting Rod
Bearing, id
.8125
8130
0.001
0.007
Bearing, side clearance
0.010
0.017
2. Cleaning, Inspection and Repair.
A. PISTONS, PISTON RINGS, CONNECTING RODS,
a. Clean all parts with an approved cleaning solvent
AND CYLINDER BLOCK
and dry thoroughly.
1. Removal and Dissembly.
a. Remove the compressor assembly Section VIII,
b. Inspect the cylinder block for broken cooling fins
C1.
and cracks. Inspect the cylinder bore for wear,
b. Refer to figure 16 and disassemble tube
scoring, pitting, or other damage. Replace the
assemblies, cooler tubes, manifolds and air
block if defective.
cleaner a shown.
c. Measure the clearance of the piston pin to the
c. Refer to figure 17 and remove hand hole plate.
piston pin bushing. Check for proper fit. Aline or
d. Refer to figure 18 and remove connecting rod
replace, connecting rods, if necessary.
bearing caps
d. Place the piston rings in the cylinder bore with
the piston ring square in the cylinder bore about
1/2 inch from the top.
CAUTION: Mark the connecting rod from which the caps
e. If the ring gap is less than the specified width,
were removed, and reassemble caps on the same rod.
file across but ends of the rings to increase the
Do not inter-mix the connecting rods and cap.
gap to, the required tolerance. If the ring gap is
greater than required, replace the entire set of
e. Disassemble cylinder block from crankcase as
rings.
shown in figure 17.
f. Measure the ring groove in the piston for wear.
f. Dissemble connecting rods, pistons and rings as
Replace pistons if necessary.
shown in figure 18.
3. Reassembly and Installation.
a. Refer to figures 16, 17, and 18 and re assemble.
NOTE: Mark connecting rod and piston to assure
and install the pistons, piston rings, connecting
correct relationship at reassembly.
rods and cylinder block taking the following
precautions:
NOTE: Do not remove the connecting rod bushings
1. If new connecting rod bushings are to be
unless inspection reveal them defective.
installed, and are not prefit, ream the
bushings.
2. When installing piston rings expand them
carefully and sufficiently to allow the ring to
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