Volvo Penta AQUAMATIC 280 Workshop Manual page 119

Repair instructions
43. Move the dial indicator gauge to the outer nut.
Measure the backlash of the rear gear the same way
as the front gear. The clearance should be 0.15–
0.27 mm (0.006–0.010"), which is 0.20–0.35 mm
(0.008–0.014") at the gear.
1
3
44. If it is necessary to increase the backlash
without changing the contact pattern, shims must be
removed from the front and rear gears (1) and shims
must be added under the vertical shaft (2) to
compensate the play.
Add the shim thickness corresponding to that
removed from gears (1) to the bearing (3) to maintain
preload.
If the backlash needs to be reduced remove shims
from gear (3) and add corresponding shim thickness
to gears (1). Compensate by reducing shim thickness
under the vertical shaft (2).
Earlier models: If new shims are installed, place
shims underneath the bearing (3). If old shims are re-
installed place the shims under the bearing race in
position (4).
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2
1
4
884795
45. Turn the vertical shaft both ways. Use the spline
sleeve 884830 while applying braking action.
Contact Pattern
46. Remove the special tool and propeller shaft bear-
ing box. Check the contact pattern on the gear wheel.
Also check the front gear wheel inside the gear hous-
ing. The contact pattern should be located towards
the big end with a slight displacement toward the root
of the tooth ("A").