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3-30
GROUP 3- SUSPENSION, STEERING, WHEELS
&
lYRES
THE POWER STEERING GEAR
DISASSEMBLY
The power steering gear is a preci-
sion machine. Therefore it is essential
that cleanliness be maintained at all
times during disassembly and assembly
of the gear, to prevent the ingress of
foreign matter which may subse-
quently affect the performance of
the
gear.
It is not good practice to
use rag for cleaning parts before
assembly into the
gear.
Preferably
parts should be washed in a petro-
leum based solvent, just prior to
assembly and allowed to drain dry.
A smear
of
power steering oil should
be applied to all rubber seals and
rubbing surfaces during assembly.
Use of Correct Tools - a list and
description of service tools is provided
in Group 21 and it is essential that
these tools be used when dismantling
or assembling the gear to ensure that
permanent damage is not done to the
components. The following service
work can only be carried out when
the gear has been removed from the
vehicle.
If a Pitman arm is still fitted to the
gear,
it must first be removed with
the aid of a hydraulic press. See page
3-44.
No
attempt
should
be
made to prise the pitman arm off by
levering against the casting, otherwise
damage will result to
the.
sector shaft
seal bore causing subsequent
leakage.
If the gear still contains oil, this must
first be removed by turning the box
upside down with the input shaft
sloping slightly downwards to posi-
tion the inlet and outlet at the
lowest point of the gear and placing
a container under the inlet and 'Outlet
to catch the oil. Most of the oil can
be removed from the gear by turning
the input shaft from lock to lock
about 6 to 8 times. Some oil will still
remain inside the gear but this will be
drained when the top cover is re-
moved as described
later.
1.
Secure the mbunting bracket
to the steering box and clamp in a
vice.
2.
Loosen and remove the four
top cover bolts.
3.
Slacken the rack adjusting
screw lock nut, and loosen the rack
adjusting screw one turn. (This is not
essential but greatly assists the re-
moval and subsequent re-a-ssembly of
the sector shaft assembly by intro-
ducing clearance between rack and
sector teeth.)
4.
Position the input shaft one
eighth of a turn off-centre towards
right lock.
.
5.
Position the gear with the top
cover turned to the bottom and the
sector shaft sloping at an angle of
about 30° to the vertical then gently
tap the end of the sector shaft with a
copper mallet whilst holding one
hand under the top cover. As the top
cover seal slides out from the bore in
the steering gear housing, position a
container to catch the remaining oil
as it drains out. Once the oil has
drained the gear should then be posi-
tioned with both input and sector
shafts horizontal.
6. Pull the top cover off the end
of the sector shaft (which will also
release a small amount of oil from
between the end of the sector shaft
and the top cover).
7. The sector shaft assembly can
then be withdrawn manually through
the top opening of the housing. Take
particular
.
care in this operation not
to allow any part of the sector to
scratch the top cover bore of the
housing as this is a sealing surface for
the top cover seal.
8. If a flange is fitted to the input
shaft of the gear this must be removed
with a puller working against the end
of the torsion
bar.
9. Using the Tool No.
XA-
3745A unscrew the piston cover en-
suring that the spanner is held ftrmly
against the cover at all times. This
cover may be very difficult to undo,
due to the rubber seal clinging to the
cover and housing. Two people may
be required to undo this cover; one
holding the spanner firmly against the
cover while the other applies a torque
to the
handle.
An extension tube may
even be needed over the handle of
the spanner.
10. Push the piston rack out of the
bore from the inside of the box. Be
careful not to damage the teflon seal
on the piston as it passes over the
threads at the end of the piston bore.
11. Lift the rack pad out of the
rack adjusting
screw.
12. Set gear with input shaft and
sector Shaft bore horizontal.
13.
Slacken the worm bearing ad-
justment screw lock nut, Tool No.
XA-
3707A, undo and remove the
bearing adjustment screw using Tool
No. XA- 3537A.
.
14. Lightly tap the end of the tor-
sion bar to remove the worm, valve
and sleeve assembly, catching the seal,
bearing race and cage as they come
out of the adjusting screw bore. With-
draw the assembly being careful not
to damage the teflon seals on the
sleeve as the assembly is drawn out of
the housing.
15. Using Tool No. XA- 3526B,
knock out the sector shaft dust seal,
this will expose the circlip which is
removed with a pair of circlip pliers.
The seal, backing ring and sector shaft
seal can now be removed by hand.
16. Using the Tool No.
XA-
3576A, press out the sector shaft
bearings. The bearings may be pushed
out in either direction.
17.
The input shaft bearing is
pressed into the bearing spacer and
these are removed as an assembly
from the housing using Tool No.
XA- 3'5 26B. The service tool should
be tapped lightly alternately against
opposite sides of the bearing spacer.
(The bearing spacer is a zinc die cast-
ing, easily damaged
if
forced exces-
sively.) The bearing and its spacer is
driven inwards into the housing by the
service tool, which is entered through
the input shaft seal. Care should be
taken not to damage the sealing lip
of the seal if it is proposed to reuse
the seal.
.
18. Once the bearing spacer and
bearing are removed, the bearing can
be pushed from the bearing spacer
using a suitable mandrel.
.
I 9. The input shaft seal can now
be removed using the same tool and
tapping the seal inwards into the
housing alternatively on opposite
sides.
20. Remove the worm bearing race
from the housing by lightly tapping
with tool entered through the input
shaft end of the bore. Shims may be
found in the bearing bore when the
race is removed, place these to one
side for use during
assembly.
INSPECTION AND OVERHAUL OF
COMPONENT ASSEMBLIES
HOUSING
Wash housing in a petroleum based
solvent and inspect for cracks. Check
the seal areas and the piston rack bore
for damage or scores.
SECTOR SHAFT ASSEMBLY
A selective assembly technique is used
in the build up of the worm follower
and its bearings into the sector shaft,
therefore these items are not serviced
individually. Little load is concerned,
but, in the rare case of wear or
damage to the follower or its bearings,
a new sector shaft assembly complete
must be fitted.
Check all bearing, seal and thrust
surfaces for wear or damage. Check
the worm follower bearings for rough-
ness or end play. Check the worm
follower and sector teeth for scoring.
Check the preload screw for binding.
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