82
The meshing is made in such a way that axial clearance between the teeth of
the worm and segment the latter being in its middle position is a minimum one
and is increasing gradually when turning the segment either side.
In a new steering gear axial travel of the segment in its extreme positions lies
within 0.30-0.65 mm, while in its middle position, within 0.05-0.10 mm.
When adjusting the meshing set axial travel of the segment in its middle po-
sition as minimum as possible (not less than 0.01 mm); in doing so, axial travel of
the segment in its extreme positions should be larger. The meshing is adjusted by
selecting shims 19; in doing so, gasket 21 under the case side cover shall retain its
thickness of 0.8 mm. The correct adjustment of axial clearance on the assembled
steering gear check using an indicator by the amount of axial travel of the segment
shaft.
Upon adjustment of the steering gear see that the steering wheel shaft rotates
freely without seizure. Marks are available on the segment face opposite the second
tooth and on the worm. When reassembling match these marks so that alignment of
the worm and segment is not disturbed.
In the steering gear
(see Fig. 59) adjust preload in bearings 14 and clearance
of meshing of nut-rack 8 with segment 1.
Screwed joint (screw 7, balls 6, nut-rack 8) and the distributor need no ad-
justment in operation. It is not allowed to disturb the set of these parts made during
the factory assembling .
1. Prior to adjustment of preload in bearings 14 grip the steering gear in the
vice by the case ears and disconnect cardan joint 28 (see Fig. 57). Cranking shaft 15
(see Fig. 60) bring nut-rack 8 (see Fig. 59) and segment 1 in one of extreme posi-
tions. Determine the torque needed for cranking through shaft 15 (see Fig. 60) from
the extreme position to the middle one (crank the shaft by an angle of about 30
°
).
Should the torque be less than 0.9 N m (0.1 kgf m), so adjust preload in bearings 14
(see Fig. 59) by reducing the number of shims 12. After adjustment the torque
needed for cranking through shaft 15 (see Fig. 60) should lie within 0.9-1.5 N m
(0.1-0.15 kgf m).
2. For checking whether a clearance is available in the meshing bring the
nut-rack and segment in their mid-position by cranking shaft 15 (the complete
number of shaft’s 15 turns should be divided in two).
Rocking the pitman arm from side to side determine, if the clearance is
available (knock in the meshing indicates its availability). Clearance availability can
be also determined by cranking shaft 15 to the left or to the right until torsion 17
begins to twist the segment being fixed. To adjust the meshing remove the pitman
arm, covers 19 (see Fig. 59) and 22 and turn inserts 21 together with bearings 18
clockwise (when viewing on the side of the segment shaft) by one and the same
angle to eliminate meshing clearance. After turning the inserts one of the insert
holes should lie in the plane passing through the opposite threaded holes in case 9
for fastening covers 19 and 22. Fit the covers in such a manner that catches 10 enter
the holes in inserts 21 and lie opposite each other. Should the catches fail to match
with the holes insignificantly, turn the inserts to one or the other side until match-
ing the catches and the holes. See that no clearance is available in the meshing.
Upon adjustment when fitting covers 19 and 22 the latter may be turned by 90
°
,
180
°
and 270
°
about their previous position.
After the covers are fitted the torque needed for cranking through shaft 15 (see
Fig. 60) in its mid-position should lie within 2.7-4.1 N m (0.27-0.41 kgf m).
