PREVOST LE MIRAGE XLII BUS SHELLS, Руководство по обслуживанию

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3-7 62--11052
c. The compressor will be fitted with double ring pistons.
Compression Ring
Compression Ring
Figure 3-18. Piston Rings
d. The compression ring is chamfered on the inside cir-
cumference. This ring is installed with the chamfer to-
wards the top. Stagger the ring end gaps so they are
on opposite sides of the piston.
3.8.3 Crankshaft and Seal End Thrust Washer
a. Two brass thrust washers are used. The pump end
thrust washer is positioned on two dowel pins located
on the bearing head and is installed with the oil pump
and bearing head assembly. The seal end thrust
washer is positioned just ahead of the seal end main
bearing on one dowel pin installed in the crankcase.
Both thrust washers should be inspected for wear and
scoring before reassembly (Refer to Table 3-2).
b. Install the seal end thrust washer on the dowel pin.
(See Figure 3-17) Ensure piston rods are pushed out
of the way and install the crankshaft.
CAUTION
Do not allow crankshaft to drop on connect-
ing rods inside the crankcase when instal-
ling the crankshaft.
3.8.4 Bottom Plate, Strainer, and Connecting Rod
Caps
a. Do not tap piston with hammer if rings are caught at
entrance to the cylinder. Using a ring compressor,
squeeze rings sufficiently to allow piston to be pushed
down into the cylinder. Ensure that ring ends are stag-
gered so that the gaps are not aligned, and lightly tap
piston down into the cylinder. (See Figure 3-19) The
ring compressor can be easily fabricated from a piece
of sheet metal.
b. Install connecting rod caps on connecting rods using
new capscrews (special) and flat washers. Reuse of
the old capscrews is not recommended. Ensure that
the caps are installed on the locating pins. Torque
capscrews to torque value shown in Table 3-1.
Ensure freedom of movement of crankshaft after
capscrews are torqued on each rod cap.
c. Check operation and reinstall check valves and relief
valve. (See Figure 3-11). The check valves are free-
floating devices and can easily be checked visually.
The relief valve is a spring-loaded device which can
be checked by using a small piece of stiff wire to en-
sure that the spring mechanism can be depressed.
Figure 3-19. Installing Pistons
d. Clean and reinstall the oil strainer.
e. Using a new gasket, install the bottom cover plate.
See figure 1-1 for relative location of compressor
mounting flanges. Torque cover capscrews, in a diag-
onal pattern, to the torque value shown in Table 3-1.
f. Reassemble the cylinder head, oil pump and shaft
seal (Refer to sections 3.4, 3.5 and 3.6 ).
3.9 SUCTION STRAINER
NOTE
The suction strainer has been preformed to fit
into the suction cavity.
Remove and clean the suction strainer. (See
Figure 3-20) Check it for damage. If it is damaged,
replace suction strainer. Install suction strainer and
suction service valve using a new gasket.
Figure 3-20. Installing Suction Strainer
3.10 ADDING OIL
Add the proper oil charge to the compressor through the
oil fill plug. Refer to section 2.2.2 for the required oil
charge. Refer to unit operation manual for other
methods of adding oil to compressor.
3.11 INSTALLING COMPRESSOR
Refer to section 2.2.2 and the unit service manual to
install the compressor.