Boss BA440 PISTON, Product Manual

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310969
Maintenance
Oil Pump Replacement
First, shut down the machine and allow it to cool for
at least 10 minutes. Verify that the entire system is
pressure relived before proceeding. Next, remove the
bolts and lift off the pump cover. Use a single edged
razor blade or putty knife to remove the old gasket
material, but make sure not to damage the machined
surfaces.
Lift the pump out of the cavity and position a new
gasket on the rear bearing housing. Next, insert the
pump into the cavity and position it slightly to one
side using a common screwdriver. Wedge the pump
into he piston so that it partially compresses the
spring. Note that the driver pin and slot in pump must
be in line. Next place the pump cover into position
and start two bolts. Strike the pump cover with a
rubber mallet to jar the pump loose. When the tension
spring can be felt against the pump cover, the pump
is lose. Now you can insert the two remaining bolts
and torque to 180 in-lbs. The bolts should be torqued
in a diagonal pattern. Finally, install the air
compressor in the vehicle and connect air lines and
wiring.
Crankshaft and Bearing
Replacement
If it is necessary to replace the crankshaft, related
components must also be replaced. Replace both
bearings, both races, the key, pump collar, and
pump drive pin.
First, shut down the machine and allow it to cool for
at least 10 minutes. Verify that the entire system is
pressure relived before proceeding. Remove both
heads, cylinders, and pistons (See Piston Ring
Replacement on pg. 16). Next, remove the bolts on
the connecting rods and lift them out. Reassemble the
connecting rods to be certain that the matched parts
remain together on the same crankshaft journals. Now
remove the pump cover, oil pump, sleeve, spring, and
rear bearing housing. Next remove the drive hub and
the front bearing housing. Next pull the crankshaft
from the crankcase and remove all gasket material
with a razor blade or putty knife.