
7.7 Repairing The Final Drive
With the final drive disassembled, inspect the parts and measure the mating surfaces.
By visual inspection, determine the condition of:
•
threaded joints (for damage to thread, rigidity of the joints)
•
oil seals
•
casing bushing, that serves as outer race for the roller bearing of the driven gear hub
•
side surfaces of the distance bushing
•
race of the roller bearing and the teeth of the driven gear hub meshing with the wheel
hub
•
ball bearings
•
Bevel gearing teeth (wear, pitting, crumbling of the working surfaces of the teeth).
Pay particular attention to the wear pattern of the gear teeth. If the gears have
damaged teeth, both pinion (final drive driving gear) and bevel (final drive driven
gear) should be replaced as a matched set, and meshing adjusted. Gear sets are
selected and run-in by pairs to ensure quiet operation.
Table 7.7-1 lists tolerated wear limits of parts related to the final drive. Parts worn
beyond the recommended limits should be replaced. It is a wise precaution to replace
all seals and gaskets.
Table 7.7-1.
Maximum tolerated limits of clearances and wear between the principal mating
members of the final drive and the propeller shaft, mm
Maximum tolerances
Name of parts and mating
members
wear on diameter
diameter
clearance
Measuring point and
method
Ring gear hub splines
Tooth thickness
0.75
Propeller shaft cross pins (journal)
0.05
On working surfaces of
journals
Final drive gears
Tooth thickness
Ring gear hub bearing
0.15
0.12
When replacing the bevel pinion and in order to remove the bearings, make use of remover
345-325-3 for the needle bearing inner race and replacer 345-320-3 for the radial thrust ball
bearing. To press out the outer race of the needle bearing from the casing, heat the bearing
to a temperature of 180 F / 75 to 90 C. Begin by pressing-out the bushing which serves as
the outer race of the driven ring gear hub and then knock out the needle bearing outer race
through the hole thus opened up.
Reverse the sequence of the operations, when reassembling the final drive. Prior to
mounting the needles into the bearings smear the fitting points with lithium bearing grease to
keep the needles from falling out when reinstalling the mating members.
The tightening torques:
•
casing cover nuts 11 ft/lbs / 13.7 to 17.6 Nm
•
pinion bearing nut 55 ft/lb. / 68.6 to 88.2 Nm
Содержание 2000 -10 series
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