Operation and maintenance manual

Section 150-0020
SM 2149 5-02
7
5. To obtain correct position of pinion relative to
crownwheel, shim (35) thickness is worked out using
formula 8.636 mm + A mm + B mm + C mm
(0.34 + 0.00A in + 0.00B in + 0.00C in) where as:
8.636 mm (0.034 in) shims selected as nominal.
'A' - Select shim thickness equivalent to figure
stamped on end face of spiral bevel pinion (33).
'B' - Select shim thickness equivalent to figure
stamped on gear casing (39).
'C' - Variation in bearing height from 44.653 mm
(1.758 in) ref. dimension.
6. Place shim pack on inner face of bearing housing
(113) then install assembly into gear casing (39).
Secure assembly in position by installing setscrews
(114) and evenly tighten to a torque of 98 - 109 Nm (72
- 80 lbf ft).
7. Fit helical gear (116) and end nut (117) onto spiral
bevel pinion (33).
8. Lock helical gear with suitable tool and tighten
end nut (117) to a torque of 1 085 - 1 220 Nm
(800 - 900 lbf ft) (See Fig. 6).
Setting Pinion Bearing Pre-load
1. Shock load spiral bevel pinion bearings.
2. Secure length of cord to helical gear (116) and
attach free end to spring balance.
3. Wrap cord around OD of helical gear (116) and pull
on spring balance to rotate spiral bevel pinion (33) (See
Fig. 7). Note the force required to maintain rotation,
ignoring initial starting force.
Note: The force required to maintain rotation should be
related in the following manner to determine pre-load.
T = F x R, where:
T = Torque
F = Force to maintain rotation
R = Radius of secured cord
Pre-load obtained should be between limits of
1.7 - 2.8 Nm (15 - 25 lbf in)
If torque reading is less than 1.7 Nm (15 lbf in) then a
smaller outer spacer needs to be fitted.
Centre Axle - Differential Drive Head
SM - 1198
Fig. 5 - Peening Pinion Nose Bearing
SM - 1180
Fig. 6 - Tightening Helical Gear Nut
SM - 1181
Fig. 7 - Measuring Force for Bearing Rotation
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