Operation and maintenance manual

SM 2149 5-02
Centre Axle - Differential Drive Head
Section 150-0020
14
4. Install outer wheel (14) and thrust washer (13).
5. Place outer cage half (12) onto assembly and secure
with bolts (126). Evenly tighten bolts to a torque of 98 -
108 Nm (72 - 80 lbf ft), then fasten in pairs with
lockwire.
6. Rotate inner wheel (15) inside cage assembly to
ensure all parts move freely.
7. Check security of studs (120) in helical gear
housing (26) and tighten to a torque of 33 - 35 Nm
(24 - 26 lbf ft) if necessary.
8. Apply a thin coating of Red Hermatite to helical gear
housing (26) face and install new gasket (20).
9. Install 3rd differential assembly onto spline of helical
pinion shaft (31).
10. Apply a small bead of Hylomar sealant to the corner
of the bearing recess in 3rd differential housing (10).
Press outer bearing (6) into housing (10).
11. Install new ‘O’ ring (11) onto the spigot on 3rd
differential housing (10) then install housing onto
helical gear housing (26).
12. Install setscrews (8), spring washers (9), nuts
(128) and spring washers (127). Evenly tighten nuts
(128) and setscrews (8) to a torque of 98 - 108 Nm
(72 - 80 lbf ft).
13. Check security of studs (129) in 3rd differential
housing (10) and tighten to a torque of 26 - 28 Nm
(19 - 21 lbf ft) if necessary.
14. Fit new oil seal (4) into front end cap (3) noting the
following:
a. Seal must be fitted using oil seal bumper tool (See
Special Tools), which bears on the seal close to its
outside diameter where the casing is strongest. Failure
to use tool will result in distortion of seal casing,
uneven wear of lip and leakage. Fig. 20 illustrates a
typical example where the seal is fitted into the seal
retainer using oil seal bumper tool.
b. Seal must remain square to the bore during fitting. If
seal cocks over and one side enters the bore first, it
will almost certainly result in distortion of the casing
which will not be corrected by straightening up the seal
further down the bore. Where possible the seal should
be fitted under a press, which reduces the likelihood of
this problem.
c. Seal must be truly square after fitting, a cocked seal
will act as an oil pump.
d. When replacing a seal, always check coupling flange
(2) surface for damage in region polished by oil seal lip;
even slight damage in this area can cause leakage.
Very slight marks may be polished out with fine emery
cloth but it is essential that polishing marks are parallel
to the seal lip. Where there is more serious damage, it
is permissible to fit two seals back to back if there is
room in the retainer, i.e. outer seal with spring facing
inwards. The outer seal acts as a spacer and ensures
that inner seal is fitted square and that it runs on a
different part of coupling surface.
e. Pack the seal with high temperature grease before
fitting.
f. The oil seal lip or journal of coupling should be
smeared with clean gear oil prior to assembly. If seal
is fitted dry, it can burn out in a matter of minutes,
before oil reaches it.
15. Apply a small bead of Hylomar sealant to the
corner of bearing recess in front of end cap (3).
16. Install washer (5) onto outer cage half (12) shaft
splines.
17. Apply Loctite 275 by brush to outer cage half (12)
shaft splines and threads.
18. Place front end cap (3) onto 3rd differential housing
SM - 1193
Fig. 20 - Method of Fitting Oil Seal
BEFORE
FITTING
AFTER
FITTING
BUMPER
TOOL
SEAL
HOUSING
OIL
SEAL
OIL
SEAL