1973 FIAT 500 shaft

CHAPTER 9
THE STEERING SYSTEM
9 : 5 Relay lever and support
9 : 6 Steering rods
9 : 7 Front wheel toe-in
9 : 8 Fault diagnosis 9:1 Description
9 : 2 Steering wheel removal and refitting
9 : 3 Steering box removal and refitting
9 : 4 Steering box dismantling and reassembly
9:1 Description
The steering gear fitted to the new 500 range of
vehicles is of the worm screw and sector type with a
steering ratio of 1:13. The steering gearbox is located on
the front lefthand side of the dash wall on the scuttle as
shown in FIG 9:1. The steering gear comprises a pitman
arm and relay lever pivoting on a pin supported on the
body. A central track rod connects the pitman arm to the
relay lever. T w o track rods connect the pitman arm and
relay lever to the knuckle arms.
9:2 Steering wheel removal and refitting
To remove the steering wheel proceed as follows:
1 Disconnect the battery positive terminal clamp and
remove the horn control from the steering wheel.
2 Remove the cable from the push button seating and the
cable insulation sleeve.
3 Using a suitably sized box spanner or Fiat wrench
A.8279 unscrew the steering wheel to shaft nut as
shown in FIG 9:2.
4 Using the palm of the hands against the back of the
steering wheel rim gently tap the steering wheel
forwards so releasing it from the inner shaft.
F50097 5 Reassembly is the reverse procedure to dismantling.
Care should be taken to ensure that the front wheels
are located in the straight ahead position when the
steering wheel is being replaced otherwise the steering
wheel spokes will not be correctly positioned.
9 : 3 Steering box removal and refitting
To remove the steering box from the vehicle proceed
as follows:
1 From inside the vehicle remove the steering column
clamp bolt 6 (see FIG 9 : 3) after flattening the lock-
washer 7.
2 From the underside of the vehicle remove the t w o
tie rod locking nuts from the pitman arm and then using
Fiat tool A.46006 or a suitable t w o leg puller withdraw
the pins from the seats.
3 Remove the three nuts holding the steering box to the
body panel. Ease out the worm screw from the
steering shaft and lift away the steering box.
4 To refit the steering box is the reverse procedure to
dismantling. The steering box to body mounting nuts
should be tightened to a torque wrench setting of
14 Ib/ft to 18 Ib/ft.

RIGHT HAND TIE ROD
RELAY LEVER SUPPORTINTERMEDIATE TIE ROD!
STEERING BOX!
LEFT HAND TIE ROD
FIG 9 :1 Steering box, idler member and steering linkage arrangement on vehicle
FIG 9 : 2 Securing steering wheel mounting nut
Key
to Fig 9:2(Tightening torque: 29 to 36 Ib ft)
9 : 4 Steering box dismantling and reassembly
1 Remove the steering gear housing cover complete
with the adjusting screw and locking nut and drain the
oil from the unit.
2 Using Fiat puller A.4005.1.5 or a universal t w o leg
puller remove the pitman arm.
3 Remove the cotter pin from the lower thrust bearing
adjusting nut and unscrew this nut.
4 Remove the sealing ring at the sector shaft lower end
and using Fiat tool A.8065 loosen the eccentric bush
adjuster plate bolt and remove both the bolt and the
adjusting plate. Also remove the upper sealing ring.
98
5 Lift out the sector together with the upper thrust
washer and shims.
6 Remove the steering worm screw by pulling out from
below. The two bearing inner rings will remain on the
worm screw whilst the lower bearing outer ring will
remain in the housing.
7 Remove the oil seal using Fiat tool A.10110 followed
by the worm screw upper bearing outer ring using
Fiat tool A.66040 or a suitably sized drift.
Inspection:
1 Carefully inspect the sector teeth and the worm screw
threads to see that there are no signs of seizure,
indentations or scoring. Check that the contact faces
indicate that meshing between the two parts is taking
place at the centre.
2 Check the clearance between the eccentric bush 5
(see FIG 9 : 5) and the worm sector 11 which must not
exceed .0039 inch. These items have an initial
assembly clearance of .00 to .0016 inch. It should be
noted that if the eccentric bushing to sector shaft
clearance exceeds .0039 inch a new bushing should
be installed and its inner face reamed using Fiat
reamer U.0360.20.
3 Ensure that the worm screw is not distorted. The
permissible out of true is .0019 inch.
Adjustment:
1 If the backlash between the worm screw and the
sector is excessive it should be adjusted by first dis-
connecting the pitman arm and its relevant seal.
Remove the screw 7 (see FIG 9 : 5) fixing the abut-
ment plate 6. Rotate the eccentric bush 5 by the
adjustment plate and move the sector in towards the
worm screw. The adjustment plate should be secured
again using the second fixing hole.
Should the adjustment plate already be fixed in the
second hole remove the plate from the bush and
rotate one or more serrations and re-secure.

FIG 9 : 3 Layout of steering gear components
Key to Fig 9 : 3 1 Steering wheel and column assembly 2 Nut 3 Toothed washer 4 Plain washer
5 Steering column bracket-to-instrument panel screw 6 Steering column-to-worm screw locking screw 7 Lockplate
8 Plain washer 9 Cover screw 10 Toothed washer 11 Cover 12 Gasket 13 Pin 14Nut 15 Plain washer
16 Worm sector adjusting screw 17 Worm sector and shaft assembly 18 Worm screw 19 Thrust washer 20 Shim
21 Splitpin 22 Lower sleeve, bearing retainer and worm screw adjuster 23 Roller bearing 24 Worm screw bearing
upper seal 25 Roller bearing 26 Steering gear housing 27 Oil filling and draining plug 28 Eccentric bushing
29 Upper seal 30 Worm screw-to-sector lash adjusting plate 31 Toothed washer 32 Plate screw 33 Lower seal
34 Pitman arm 35 Self-locking nut Inset: Universally-jointed column fitted from late 1971
99F500

reassembling and during assembly liberally lubricated
using Fiat W90/M oil (SAE90 EP).
2 The pitman arm nut should be correctly positioned on
reassembly to the sector shaft and both are marked
with notches or a master tooth on the sector will mate
with a double tooth on the pitman arm which will
prevent incorrect reassembly.
3 The pitman arm nut must be tightened to a torque
wrench setting of 72 Ib/ft.
4 Fill the box up to the level and filler plug with SAE90 EP
gear oil.
Refitting the steering box:
To refit the steering box to the vehicle proceed as
follows:
1 Engage the w o r m screw f r o m the steering shaft by
gently manipulating the steering box.
2 Replace the steering box to body nuts and tighten to a
torque wrench setting of 14 to 18 Ib/ft.
3 Replace the t w o track rod pins in their seatings in the
pitman arm and tighten the self-locking nuts to a
torque wrench setting of 18 to 21 Ib/ft.
4 Replace the steering shaft to worm screw mounting
bolt, lock washer and nut.
9 :5 Relay lever and support
The steering idler arm is secured to the body by means
of a support bracket and a rubber bushed pivot bolt. This
is shown in FIG 9 : 7. When this unit is being serviced
the following points should be noted.
1 If there is excessive play between the pin and the
bushes the bushes must be renewed. Also check the
condition of the pin and if there are signs of excessive
wear it must be renewed.
2 To eliminate torsional stresses in the rubber bushes
during assembly the pin nut must be tightened to
torque wrench setting of 39 to 43 Ib/ft, once the
front wheel toe-in has been correctly adjusted w i t h the
wheels set in the straight ahead position.
3 The relay lever support to body mounting nuts must
be tightened to a torque wrench setting of 14 to 18
Ib/ft.
9 : 6 Steering rods (tie rods)
The steering rod is connected to the idler arm and the
drop arm by means of non-adjustable ball joints. The
track rods are connected to the right and left steering
arms by non-adjustable ball joints and comprise t w o
sleeves which are split and having internally threaded
ends. The ball joints are clamped to either end of the
sleeves. To facilitate adjustment one ball joint end has a
lefthand thread and the other a righthand thread.
Adjustment is made by loosening both the clamping bolts
and turning the central sleeve.
To remove the steering rods from the pitman arm, the
relay lever and knuckle arms Fiat pullers A.46006 and
A.6473 or universal ball joint removers should be used.
If excessive play is evident in the ball joint linkage or
the pin is damaged the complete ball joint assembly must
be renewed.
Upon reassembly the tie rod to ball pin knuckle arm
nuts must be tightened to a torque wrench setting of
18 to 21 Ib/ft.
F500101
FIG 9:7 Relay lever support section
FIG 9:8 Front wheel toe-in checking diagram
Key to Fig 9:8 A—B = 000 inch to .079 inch
It is important that all steering linkages are thoroughly
checked at regular intervals and if any parts are suspect
then they must be renewed.
9 : 7 Front wheel toe-in
To check and adjust the front wheel toe-in proceed as
follows:
1 Ensure that the tyres are inflated to the recommended
pressures. Ensure that the steering wheel is in its

indicates a break in the cable from the generator to
regulator. Repeat the test on terminal 67. Finally,
remove the temporary link from the generator. If the
readings are correct, test the regulator as described in
Section 11:5.
Removing generator:
1 Disconnect the leads from the generator.
2 Remove the drive belt as previously described.
3 Release t h e rear mounting bracket at the side of the
power unit.
4 Remove the air cooling ducting from around the fan
and generator area and lift away the unit.
5 Release the blower from the end of the armature shaft
and finally, the mounting bolts from the air ducting.
Dismantling generator:
1 Release the pulley self-locking nut and slide the pulley
off the armature shaft.
2 Remove the t w o Woodruff keys on armature shaft.
3 Unscrew the t w o through bolt nuts and pull out the
bolts.
4 Partially remove the commutator end head to the point
where the brushes are. s t i l l seating on the commutator.
Using a piece of hooked wire relieve the load of the
springs on the brushes by arranging the spring ends
on the brush sides. The brushes will be locked in their
holders and cannot be chipped by striking against the
armature shaft during the commutator end head
removal.
5 Gently ease the commutator and fan end heads apart
and, slide out the armature.
Servicing brushes:
Lift the brushes up in the boxes and hold them in that
position by letting each brush spring bear on the side of
its brush. Fit the commutator end bracket over the
commutator end of the armature shaft and release the
brushes by hooking up the springs using a thin screw
driver. Hold back each spring in turn and move the brush
by pulling gently on the flexible connector. If the brush
moves sluggishly remove it and polish the sides using a
smooth file. Before this operation is actually carried out it
is suggested that the brush is marked before removal so
that it is replaced in its original working position.
inch,The minimum permissible length of a brush is
so renew any t h a t are less than this figure. Test the brush
springs using a spring tension scale. New springs should
have a tension of 1.3 to 1.6 Ib. In service this value could
fall slightly before performance is affected. Always bed in
new brushes by wrapping fine sandpaper round the
commutator, pressing down on the brush and rotating
the commutator under it, or draw the paper t o o and f r o .
If new brushes are fitted always fit genuine Fiat replace-
ments.
Servicing the commutator:
A commutator in good condition should be smooth and
free from pitting or signs of the segments burning. Clean
with a rag moistened in petrol. If necessary, polish using
a fine glasspaper whilst rotating the armature. Never use
emerycloth.
If the commutator is badly worn it may be skimmed
using a centre lathe. Use a high rotational speed and take
F500113
FIG 11 :3 Components of generator
Key to Fig 11 : 3 1 Terminal 51 2 Bearing outer ring
retainment terminal nut 3 Commutator end head 4 Brushes
5 Terminal 67 6 Frame 7 Blower end head
8 Bearing retainer nuts and screws 9 Pulley retainment nut
10 Pulley 11 Head mounting tie rods and nuts
12 Armature 13 Blower retainment nut
FIG 11 :4 Commutator end head of generator DSV
90.12.16.3 S
a light cut using a sharp tool. Remove only enough metal
to clean up the commutator face and then polish with
fine glasspaper. To undercut the insulation between the
segments, it is suggested that a hacksaw blade is ground
on its sides until it is the thickness of the insulation and
carefully work between each pair of segments until the
insulation has been cut to a depth of .0394 inch below the
surface.
A thorough visual inspection may determine the cause
of armature failure. Breaks in armature windings cause
burnt commutator segments. Short-circuited windings
are discoloured by overheating, with badly burnt
commutator segments.

1
791011 8 234
11
10
16,15
14 13
1265
FIG 11:5 Components of starter
Key to Fig 11:5 1 Drive end head 2 Head shield 3 Frame 4 Switch 5 Commutator cover band
6 and 7 Pin and spring for lever 8 8 Starting engagement lever 9 Head shield 10 and 11 Head fixing tie rods and tubes
12 Pinion, complete 13 Starting engagement spring 14 Drive unit sleeve and free wheel hub 15 Armature
16 Commutator end head
Testing field coils:
When tested w i t h an ohmmeter the reading should be
8+.1—.3 ohms. Failing an ohmmeter use a 12-volt
supply and connect it in series w i t h an ammeter across
the field terminal and the yoke or body. The meter should
read approximately 2 amps. If there is no reading the
field coil winding has a break in it. If the reading is much
more than 2 amps or the ohmmeter records at much less
than 8 ohms it shows that field coil insulation has broken
down. Renewal of the field coils is a specialist operation
best left to a service station.
The armature:
Apart from reconditioning the commutator, there is
little which can be done to the armature itself. Never try
to straighten a bent shaft and do not machine the arma-
ture core. Armature windings are tested w i t h equipment
normally not available to the car owner. The only check
for a suspected faulty armature which the owner can do
is to substitute an armature which is known to be
satisfactory.
Generator bearings:
1 Commutator end head bearings. Remove the ball-
bearing outer race stop bracket mounting screw and
nut, ease o u t t h e stop brackets and the ballbearings.
2 Fan end head bearing. Remove the ballbearing retainer
mounting screw nuts and ease o u t t h e retainers and
the seals. Using a suitably sized drift remove the ball-
bearing.
114Reassembly is the reverse procedure to dismantling
in both cases.
Reassembly and refitting the generator:
This is the reverse procedure to dismantling. The
following points should however be noted.
1 The commutator end head ballbearing outer race stop
bracket mounting screw nut must be tightened to a
torque wrench setting of .80 Ib ft.
2 The pulley and fan-to-generator armature shaft self-
locking nuts must be tightened to a torque wrench
setting of 14.5 Ib ft.
3 To assemble the commutator end bracket to the yoke,
partially withdraw the brushes and trap them in this
position by letting the springs bear on the sides of the
brushes. Fit the bracket to the armature shaft and when
it is about 1/2 inch from the yoke face, lift the springs
using a thin screwdriver or a piece of hooked wire and
this will let the brushes drop onto the commutator.
Check that the springs now bear correctly on the tops
of the brushes and push the bracket fully home.
4 Pack all ballbearings with Fiat Jota 3 grease or an
equivalent grade grease.
11:4 The starter motor
Operation:
When operating the starter hand lever through a
flexible coupling a lever is operated (see FIG 11:5)
which controls the pinion engagement with the flywheel.
As the lever completes its movement it closes the starter

switch contacts. The starter motor rotates driving the
engine through the pinion and ring gear. As soon as the
engine fires the starter hand lever must be released which
will open the starter switch contacts so stopping the
starter motor and the pinion will return under the action
of a spring to a neutral position.
Tests for a starter which does not operate:
Check the condition of the battery and particularly
the connections to the terminals and to earth. If the
battery is charged, switch on the lights and operate the
starter hand lever control. If the lights go dim but the
starter does not operate it shows that current is reaching
the starter motor. The probability is that the pinion of the
starter shaft is jammed in mesh due to dirty pinion splines
or a broken spring. To release the pinion engage a low
gear with the ignition switched off and rock the vehicle
backwards and forwards which should allow the pinion
to be disengaged from the flywheel ring gear. If it proves
impossible to free a jammed pinion the starter motor must
be removed for examination and repair.
If the lamps do not go dim, check the starter switch and
also check the connection between the battery and the
starter switch to ensure that they are tight and making
good electrical connection. If the starter motor still does
not work it should be removed from the power unit for
inspection.
Removing the starter:
To remove the starter motor from the power unit
proceed as follows:
1 Disconnect the positive terminal from the
battery post.
2 Release the hand lever control cable from the starter
motor engagement lever.
3 Disconnect the battery cable terminal from the starter
motor switch.
4 Remove the retaining nuts and washers holding the
starter motor to body to the transmission bellhousing
and gently ease backwards and lift away the starter
motor.
Examining the commutator and brush gear :
Refer to FIG 11:5 and remove the coverband 5. Hold
back each spring in turn and pull gently on the flexible
connection to the brush. If the brush does not move
freely remove it from its holder and polish the sides using
a fine file. Mark the brushes so that they will be replaced
in their original positions. If the brushes are so worn that
they no longer bear onto the commutator, or the brush
connector has become exposed on the running face, the
brushes must be renewed.
If the commutator is blackened it should be cleaned by
turning it against a petrol-moistened cloth. With the
brushes and commutator overhauled hold the body of the
starter motor in a vice and connect it with thick cables to a
12 volt battery. One cable should go to the starter
switch terminal and the other to the body of the starter.
The starter should run at high speed. If it does not, it
must be dismantled for further examination and testing.
F500115 Dismantling the starter:
To dismantle the starter proceed as follows:
1 Remove the coverband 5 (see FIG 11:5) and hold
back the brush springs and take out the brushes.
2 Remove the starter switch by releasing the t w o
mounting screws and lift away the switch.
3 Remove the commutator end head 16, slide off the
armature assembly from the drive unit and from the
pole shoes.
4 Release the engagement lever pin 6 and spring 7 from
the lever operating bracket on the drive end head. Lift
away the lever and withdraw the pinion assembly
complete which is shown in FIG 11:5.
Servicing the brushes
Test the brush springs with a balance, the correct
tension is 2.5 to 2.9 Ib. according to the wear of the
brushes. Fit a new spring if the tension is low.
The life of the brushes depends on the type of service
in which the vehicle is being used. In normal circum-
stances even when the starter is being used frequently,
the brushes should last more than 18,000 miles. If the
wear is found to be abnormal it will probably be found
that the commutator is either damaged or excessively
w o r n . Only Fiat replacement brushes must be used.
Testing the field coils:
Use a 12 volt bulb in one lead of a 12 volt battery.
Connect one lead to the brush connection joint to the coil
field and the other to the field coil current supply lead.
If the bulb does not light there is a break in the f i e l d coil
windings. This is not a complete test as it is still possible
for a coil to be earthed. Check this by moving the lead
from the brush connection and holding it on a clean
metal
surface on the yoke or body. If the bulb lights it shows
that the field coils are earthed.
The only sure way of curing faulty field coils is to take
the starter motor to a service station.
Examining the armature:
The armature shaft may be bent due to the starter
being operated whilst the engine is operating. Do not try
to straighten a bent shaft or machine the armature core to
obtain the correct clearance.
If the commutator is damaged or any wires or segments
have lifted from it, the assembly will have to be renewed.
Starter bearings:
Bearing bushes are of the porous bronzed type and
must not be reamed after fitting. Worn bearings should
be withdrawn by screwing a tap into them and pulling
on the tap. New bushes must be immersed in engine oil
for approximately twenty four hours before fitting. Press
them into place using a suitably sized drift which has a
spigot the length of the bearing and the diameter of the
starter shaft. When this is withdrawn after fitting, the
bore of the bush should be correct to size.
The pinion drive:
This unit is shown in FIG 11:5. The chief sources of
trouble are a dirty unit or a broken starting engagement

WINDSHIELD WIPER
MOTOR ASSY
WIPER MOTOR SCREWS
WIPER MOTOR BRACKET
FIG 11:15 Arrangement of windshield wiper unit on
vehicle
B M INT F
SC12 V
31
D
A
SWITCH PARKING
0 ON
SWITCH LEVER POSITIONS
FIG 11:16 Windshield wiper wiring diagram
Key to Fig 11 :16 A Series winding B Shunt winding
D Switch M Motor S Additional winding F INT
C =Terminals
120signal lamp pairs. The flasher unit connections are in
FIG 11:14 and the unit is of the hot wire type.
Faulty operation of flashers:
In cases of trouble check the bulb for broken filaments.
Refer to the wiring diagrams in Technical Data and check
all flasher circuit cables and connections. Check the
appropriate fuse. Switch on the ignition and check w i t h
a voltmeter between flasher unit positive terminal and
earth to see if battery voltage is present. Connect together
flasher unit positive terminal and L and operate the
direction indicator switch. If the flasher lamps now light,
the flasher unit is defective and must be renewed. It is not
possible to dismantle and repair a faulty flasher unit.
Before removing make a note of the connections so that
they will be replaced correctly when the new unit is being
installed.
Before making the connections it is advisable to check
the circuits to ensure that the new flasher unit is not
damaged by wrong connection. Test by joining the
cables normally connected to the unit and operate the
switch. If the connections are wrong the appropriate
fuse will blow but no damage will be done to the flasher
unit.
Never insert terminal L directly to earth without having
first connected in series the bulbs specified, otherwise
the flasher unit will be damaged. For the same reason
terminal L must never be shorted to ground nor must there
by any short circuits in any of the leads from the L
terminal to the bulbs. The flasher unit must never receive
blows of any kind since it is a very delicate component
and easily damaged.
11:8 Windscreen wipers
Description:
The windscreen wiper assembly comprises a motor
unit that drives t w o wiper blades through a reduction
gearing and mechanical linkage. The reduction gear
includes a worm screw on the motor armature shaft and a
helical pinion. The motor, left blade pivot and linkages
are mounted on a sheet metal bracket, whilst the right
blade pivot is connected to the main drive link. When
assembled to the vehicle the right blade pivot is fixed
directly onto the body. The unit is provided w i t h an
automatic parking device which ensures that the blades
return to their correct park position. The w
indscreen wiper
is- controlled by a lever switch with three separate
positions on earlier models or a simple on-off switch on
later models.
Maintenance:
Maintenance is confined to the changing of the wiper
blades when they have deteriorated and occasional
lubricating of the mechanical linkage.
Wiper unit faulty operation :
1 It is important that the wiper unit assembly is correctly
fitted to the body otherwise distortion of the wiper
mounting bracket can occur which will cause
abnormal stresses on the pivot and linkages resulting
in irregular and difficult blade sweep.
2 If the blades keep on sweeping at a reduced speed
although the switch lever has been pressed to the