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3-36
GROUP
3-
SUSPENSION, STEERING, WHEELS & lYRES
Fig. 53. Centre Tooth Gap
of Rack in Line with Sector Shaft Bush
24. If the original sector shaft seal
is still in position it is in order to
assemble the sector shaft directly
through the seal, provided the splines
are smoothed to remove sharp edges
or covered with plastic tape. If how-
ever, a new sector shaft seal is to be
fitted, it is advisable to fit the new
seal after the sector shaft has been
fitted, using plastic tape to mask the
sector spline and push the seal home.
25. Enter the sector shaft assembly
carefully through the top cover aper-
ture into the sector shaft bearing.
Keep the rack parallel to the bottom
of the box and roll it slightly to open
the mesh at entry. It is essential to
see that the centre tooth of the sector
shaft is aligned with the tooth gap in
the rack as the sector shaft is pushed
in. Use a torch if necessary. At the
same time as the rack and sector
teeth are engaging, the input shaft
will need to be turned to align the
groove in the worm with the follower
on the sector shaft assembly. The
sector shaft assembly must never be
hammered in during this operation.
If difficulty is encountered, slacken
the rack adjusting screw as described
under "Preload Adjustments'?
26. Position the gear slightly off
centre to ensure the sector shaft is
not displaced by any preload between
the follower and worm. Then fit the
top cover over the sector shaft journal
and enter it into the steering gear
housing. A new seal should be fitted
if the old seal shows any sign of
fretting or if it has lost its sharp
corners. Care should be taken as the
seal is entering the aperture to ensure
it is not pinched. Once entered, the
top cover may be lightly tapped
home. A smear of power steering oil
on the seal will greatly assist the fit-
ment of the top cover.
27. Fit the four screws securing
the top cover but do not tighten.
28. Remove the recessed head plug
from the top cover and position the
gear on centre. Force the top cover
back against the housing aperture by
applying a temporary follower pre-
load of 8-12 inch ounces (to avoid
subsequent loss of preload in service
due to shifting of the cover) and with
the gear still op. centre, tighten the
four top cover bolts to 30 ft. lbs
torque. The recessed head plug will
be replaced after preload adjustment.
(Refer instructions for setting pre-
loads.)
·
29. With the sector shaft splines
covered with one layer of plastic
tape fit the sector shaft seal, with the
lips towards the housing,
Fit the backing ring with its rounded
side towards the seal and its flat side
towards the circlip. (This is important
to ensure that the circlip is loaded
close to the groove in the housing
otherwise it will fatigue in service.
The rounding of one side of the
backing ring is a legacy of the blank-
ing operation during its
.
manufac-
ture). Finally, fit the circlip then the
dust seal using the special service
tool.
30. Install the flexible coupling to
the input shaft, making sure to line
up tpe master spline, the lock plate
and nut. Torque to specification.
31
.
Set all preloads as described
on following pages.
SETTING
PRELOADS ON THE
STEERING
GEAR ASSEMBLY
General
During production of the steering
gear assembly preloads are set slightly
higher than in service to allow for
initial 'bed-in' of mating components.
These higher preload figures are given
below in brackets and should only be
used where new components are
being fitted to the steering
gear.
Before setting preloads, the gear
should be substantially drained qf
power steering fluid, otherwise the
readings obtained will be too high
because of the pumping action of the
piston moving oil from one end of
the cylinder to the other. Most con-
sistent results are obtained if the box
is warm.
In order to establish the correct
preloads the sequence of
preload·
settings following should be strictly
adhered to as each reading obtained
is a cumulative reading of the preloads
set before. The gear must be removed
from the vehicle to set preloads and
should preferably be mounted in the
special service ftxture in a vice with
the input and sector shafts horizontal.
First, undo and remove the plug from
the top cover. Position the gear
roughly 'on centre'. (The gear is 'on
centre' when it is positioned midway
between full left and right lock; in
this position the blocked splines on
the sector shaft lie parallel and at
right angles to the plane of the
mounting feet and the flat on the
input shaft is in line with the inlet
and outlet ports.) The socket head of
the adjusting screw for the worm
follower will now be visible through
the top cover plug hole. ·Turn this
screw 2 to 3 turns anti-clockwise to
remove any preload from the worm
follower, at the same time keeping
pressure on the Allen key to hold the
adjusting screw head against the end
of the sector. Loosen the lock nut on
the bearing adjusting screw and undo
the bearing adjusting screw
*
to 1
turn to remove any preload from the
worm bearings. Loosen the rack adjus-
ting screw locknut and undo the rack
adjusting, screw
*
to 1 turn. This will
remove any preload between the rack
and the sector teeth. The gear is now
ready for setting the preloads, which
are measured at the input shaft using
a torque meter (having a range 0 to
20 inch pounds in both clockwise and
anti-clockwise direction).
1.
Input Seal Friction
Turn the input shaft of the steering
gear to either left or right lock. If the
input shaft is oscillated
·
4 or 5° in
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