6). Undo the fastening bolt, take off cover 12 (see fig. 5-5) of the
steering box together with cap, adjusting screw 8, adjusting plate
9, lock washer 10 and jam nut. Take out from the steering box 1
the pitman arm shaft 7 in assembly with the roller.
Undo the fastening bolt, remove cover 3 from the worm shaft
thrust bearings together with shims 4.
With the worm shaft 11 push out from the box the bearing
outer ring 5 and take out the shaft together with bearing cage 6.
Remove worm shaft sealing 15 and the pitman arm sealing 16.
Using tool 67.7853.9541 take out the top bearing outer ring
(fig. 5-7).
Reassembly.
The reassembly of the steering mechanism is
carried out on bracket A.74076/R in sequence, reverse to dis-
mantle.
The outer ring of the worm upper bearing is press-fitted with
tool 67.7853.9541, having rearranged the fixture on the tool han-
dle in reverse order.
Refit the worm in the steering box and fasten the bottom
cover (fig. 5-8), use dynamometer 02.7812.9501 and head
A.95697/5 (fig. 5-9) to check the worm friction moment; it should
be within the limits of 19.6-49 N•cm (2-5 kgf•cm). If the moment
will appear less than specified, reduce the thickness of shim 2
(see fig. 5-8), and if more - increase.
After refitting the pitman arm, ensure there is no clearance in
the roller-to-worm mesh in position when the worm shaft is turned
right and left by 30
°
from the pitman arm middle position. Take up
any possible clearance by adjusting screw 2 (see fig. 5-2) and
tighten jam nut 4.
After adjusting the roller-to-worm mesh gap, use a
dynamometer to check the worm friction, which should be equal
to 68.7-88.3 N•cm (7-9 kgf•cm) when turning the worm shaft by
30
°
both to the left and to the right from the middle position and
should smoothly reduce to 49 N•cm (5 kgf•cm) when turned from
the 30
°
position further to the stop.
After the reassembly, check the angles of pitman rotation from
the neutral position, which should make 32
°
10' ± 1
°
both to the left
and to the right until the pitman arm will get pressed against the
bolt head; fill the steering box with 0.215 l of transmission oil.
Check and repair
Carefully examine the working surfaces of the roller and the
worm for traces of wear, jamming or risks. Renew worn and dam-
aged components.
Check the size of the clearance between the bushes and the
pitman arm shaft, which should not exceed 0.10 mm. If the clear-
ance is more than specified, renew the bushes using tool
A.74105.
On the inner surfaces of the pitman arm bushes there are spi-
ral flutes, which come out only from one side. When press-fitting,
the bushes should be located so that their end faces with the flutes
were inside the aperture of the steering box, and the outputs of the
flutes were facing each other. The end faces of the bushes should
be deep inside the steering box aperture by 1.5 mm.
New bushes should be greased with transmission oil before
press-fitting.
119
Fig. 5-9. Checking the worm friction moment using a dynamometer:
1 - worm; 2 - head A.95697/5; 3 - dynamometer 02.7812.9501; 4 - test-bench
bracket; 5 - steering box
Fig. 5-10. Removing the ballpins
Fig. 5-8. Installing the steering worm
1 - bearing cover; 2 - shim; 3 - worm
Summary of Contents for Niva 4x4
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