1958 FIAT 500 ECO mode

FIG 1:21 Finned cylinder. Letter A stamped on cylinder
indicates the class to which cylinder belongs, as referred
to its inside diameter
CLASS LETTER
FIG 1 :22 Cylinder measurement points
seats, gearbox companion flange and timing gear cover
mounting flange.
The cast iron cylinders are finned radially to increase the
cooling air surface and are located symmetrically on the
crankcase, each being held by four studs. The cylinders are
installed by sliding into the crankcase bores and finally
held in place by the cylinder head (see FIGS 1 :8 and
1 :21).
Inspect the cylinder bores for score marks, wear and
any other defects or damage. The clearance between the
piston maximum diameter and the cylinder bore should be
checked to ensure that it is within the maximum wear limit
of .0059 inch.
20FIG 1 :23 Checking cylinder diameter by dial gauge
C.687 brought to zero w i t h ring gauge C.672 DIAL GAUGE C 687
RING GAUGE C. 672 The cylinder height must be checked between the seat-
ing face on the crankcase and the top surface and this
dimension should be 3.5433 ±0006 inch.
If this dimension is less than specified the cylinder must
be renewed to prevent possible carbon deposits on the
piston crown and underside of combustion chamber
causing the piston to strike the cylinder head (see
FIG 1 :24). Checking cylinder height: This operation should bring the bore size to correspond
to the oversize piston sizes in order to obtain the correct
clearance between the piston and cylinder. These
limits
are given in Technical Data. It will be observed that the
cylinders are divided into three classes depending on the
bore diameter. The classes are identified by the letters 'A',
'B
1 and ' C , one of which will be stamped on the mating
face with the cylinder head as shown in FIG 1 :21. Pistons
are divided into three classes to correspond with the
cylinder bore sizes. Naturally the piston and bore must
belong to the same class. The maximum available piston
oversize is .0236 inch.
Pistons and rings for the Model 500 sports engine are
not available in oversize dimensions so if the cylinder bore
diameter is above the maximum wear limit new parts must
be fitted.Honing or reboring cylinder bores: It is essential that the diameter measurements are taken
at t w o different heights in the cylinder bore along both the
longitudinal and transverse axles as shown in FIG 1 :22.
It is recommended that to zero the internal micrometer
Fiat ring gauge C.672 is used (see FIG 1 :23).
If bore wear or ovality is between .0059 and .0079 inch
the cylinder bore may be honed. Should however the
wear limit of .0079 inch be exceeded then the bores must
be recut.

3:1
3:2
3:3
3:4
3:5Description
Operation
Routine maintenance
Ignition faults
Removing and dismantling distributor (sedan
and sports)
CHAPTER 3
THE IGNITION SYSTEM
3:6
3:7
3:8
3:9
3:10
Removing and dismantling
(station wagon)
Timing the ignition
Sparking plugs
The distributor drive spindle
Fault diagnosisdistributor
3 :1 Description
The ignition system fitted to all the models covered by
this manual consists of an ignition coil, ignition distributor
fitted with contact breaker points, a centrifugal automatic
advance system, condenser, low- and high-tension
wiring, spark plugs and a power supply provided by a
generator and battery. The wiring diagram is shown in
FIG 3 : 1
1 The low-tension circuit which is sometimes called the
primary circuit includes the power supply, contact
breaker points, condenser and ignition coil primary
winding.
2 The high-tension circuit which is sometimes called the
secondary circuit includes the ignition coil secondary
winding, distributor rotor, distributor cap with terminals
and the central brush, high-tension cables and the spark
plugs.
3 : 2 Operation
The contact breaker unit in the distributor interrupts
the primary circuit by the points opening. The sudden stop
in the flow of current in the primary winding, does not cause
arcing at the contact breaker points because it discharges
into the condenser connected in parallel w i t h the contact
F50047
breaker points. With the sudden collapse of the primary
circuit, the intensity of the magnetic field drops causing
an induced high-tension current in the ignition coil
secondary winding. The high EMF is distributed to the
sparking plugs by the ignition distributor rotor.
The automatic advance mechanism comprises a plate
carrying t w o weights which are symmetrically pivoted on
the plate at one end. Also attached to the weights at
opposite ends to the pivots is the cam carrier shaft with
special tension return springs. Under the action of centri-
fugal force as the rotational speed increases, the weights
move outwards causing the cam carrier shaft to move
angularly compared to the distributor drive shaft thus
causing advancement of the ignition timing.
The contact breaker assembly comprises the cam on the
drive shaft and t w o contact points, one of which is
stationary while the other is under the influence of the
cam, the action of which is transmitted by a rubbing block.
The cam has t w o lobes to control the opening and closing
of contact points. The stationary contact point is mounted
on an adjustable support to enable the contact breaker
point gap to be adjusted.
The HT current reaches the distributor cap central
terminal, from the ignition coil and is distributed to each
of the spark plugs at the correct time by the rotor arm.

FIG 3 : 4 Use of fixture Ap.5030/1 to check ignition
timing
Reassembly is the reverse procedure to dismantling but
the following points should be noted:
1 Lubricate the parts of the centrifugal advance mecha-
nism, the drive spindle and the part of the shaft which
accepts the cam w i t h Fiat VS oil.
2 Ensure that upon reassembly the slot in the rotor arm
housing matches the distributor driving dog. Lubricate
the felt pad in the rotor arm housing.
3 Fit the distributor back onto its support gently rotating
the rotor arm so that the drive dog engages w i t h the
drive shaft mating flange. Provided the crankshaft has
not been turned the rotor arm should finish up pointing
to No. 1 cylinder segment in the distributor cap. Tighten
the distributor retaining nut, refit the distributor cap and
leads to the spark plugs and the LT lead to distributor
body terminal.
4 Add a few drops of oil to the distributor shaft lubrication
fitting (see FIG 3:3).
3 : 6 Removing and dismantling distributor
(station wagon)
The distributor is located towards the top rear of t h e
engine and is bolted direct onto the crankcase rear cover as
shown in FIG 1 : 2 . It is driven direct by a gear in mesh w i t h
a corresponding gear on the camshaft. The basic design of
the distributor is the same as that for the sedan and sports
engine, except that the distributor cap has been redesigned,
there is a gear instead of the dog
drive and no distributor
support. To remove and dismantle the distributor proceed
as previously described taking great care about marking
the location of the distributor to rear cover and rotating
the engine until No. 1 cylinder is on compression. This will
ensure that reassembly is straightforward without loss of
ignition timing.
503:7 Timing the ignition
It is necessary to retime the ignition should the distribu-
tor shaft or camshaft have been removed. To retime the
ignition proceed as follows:
1 On the timing sprocket cover fit Fiat tool AP.5030/1 as
shown in FIG 3 : 4. Ensure No. 1 cylinder is on the
compression stroke with both valves closed. Rotate the
crankshaft until the mark on the centrifugal filter cover
lines up w i t h the 10° mark on the fixture. This setting
corresponds to a 10° static advance BTDC.
2 Check t h a t the points gap is correctly set between
.018 and .020 inch. Turn the distributor shaft until the
rotor points in the direction of No. 1 segment in the
cap and the points are just opening.
3 Without disturbing the distributor shaft, insert the lower
coupling on its toothed end, install the support and
tighten the locknut. Secure the distributor to the sup-
port using the mounting screw.
To check that the distributor is properly timed to the
engine and the centrifugal automatic advance is operating
correctly giving a
total advance of 18° to 28° respectively
proceed as follows:
1 Connect Fiat timing tester AP.5030 with a 220-volt-
single-phase power outlet fitted with a good earth
connection. It is important that the tester is earthed
before it is allowed to operate. Also ensure that the
tester earth terminal is connected to a bare metal part
of the vehicle.
2 Remove No. 1 spark plug lead, insert the strobe light
adapter and reconnect the spark plug lead. Using a
piece of white chalk mark the TDC position on the
centrifugal filter cover.
3 Start the engine and aim the strobe light beam towards
the chalk mark drawn on the centrifugal filter cover.
With the engine running slowly the mark on the centri-
fugal cover must correspond wi th the first white line
on the fixture (10°). Slowly increase the speed of the
engine so operating the automatic advance and the
chalk mark should move counterclockwise until at
maximum speed it reaches the second white mark on
the fixture.
It should be noted that the ignition timing for the model
500 sports engine the static advance is 10°, an automatic
advance of 12° giving a total advance at maximum engine
speed of 2 2 ° .
Should Fiat fixture AP.5030/1 not be available the
advance position may be set as follows:
1 Turn over the
engine until No. 1 piston is on the com-
pression stroke w i t h both valves closed.
2 Rotate the crankshaft clockwise until the reference
mark cast on the centrifugal filter cover is set .5118 to
.5512 inch ahead of the arrow cast on the timing
sprocket cover. This will give a static advance setting
of 10° BTDC.
3 Proceed as directed for ignition distributor timing and
mounting described earlier in this section.
3 : 8 Sparking plugs
The sparking plugs must be regularly inspected, cleaned
and the electrode gap adjusted to a gap of .019 to .023
inch.
The inspection of the deposits on the electrodes is par-
ticularly useful because the colour and type of deposit

FIG 7:9 Adjusting rear wheel toe-in on '500 StationWagon'
FIG 7:10 Checking left rear wheel toe-in
84
6 Insert the inner spring between the axle shaft and the
wheel shaft and couple the spline sleeve to the joint
and tighten the screws to a torque wrench setting of
20.3 Ib/ft.
7 Reconnect the parking brake tie rod and adjust the
position of the cable using the two stretchers.
8 Refit the wheels and draw up the mounting screws to
a torque wrench setting of 32.5 to 39.8 Ib/ft. Carefully
lower the vehicle to the floor.
7 :6 Checking and adjusting rear wheel toe-in
This check should be carried out by a Fiat agent as
special setting equipment is necessary. However, details
of this check are given for reference purposes:
To check and adjust the rear wheel geometry proceed
as follows:
1 Place the vehicle on firmly based stands and remove
the front and rear wheels.
2 Install Fiat fixtures A.66062 as shown in FIG 7:12 to
enable correct spring compression and wheel location
in the vertical position.
3 Lift the rear suspensions by compressing the coil
springs and shock absorbers using garage hydraulic
jacks. Screw on the fixture lower shank until the
index registers with the mark 'Nuova 500' stamped on
the bracket. In this position the wheel plane is vertical
and the centre O (see FIG 7 : 6) of wheel shaft results
at 5.00 inch from the buffer stop bracket.
4 Secure Fiat support C.696/3 to the wheel drum and
connect gauge C.696 to the support. Tighten the two
clamping screws as shown in FIG 7:12.
5 Apply at the front of Fiat gauge C.696 bracket
numbered C.696/3 as shown in FIG 7:11.
6 Check that the pin mounted on the front end of the
bracket C.696/3 is in touch with the front suspension
swinging arm pin (see FIG 7:11). If these conditions
are not complied with, proceed with item 7.
Wheel toe-in angle
will vary by 0° 10' under
a movement of some 7/32 inch measured at 72.476 inch
from wheel centre for Model 500D, and at 76.413 inch
from wheel centre for 500 Station Wagon NOTE - - that the toe-in angle
Key to Fig 7 : 9 A Front support B Screw holes for
fixing support to underbody C Swinging arm pin nuts

CHAPTER 10
THE BRAKING SYSTEM
10:1 Description
10:2 Maintenance
10:3 Front brakes
10:4 Rear brakes
10:5 Master cylinder
10:6 Wheel cylinder10:7 Self-adjusting device
10:8 Removing a flexible hose
10:9 Brake fluid reservoir
10:10 Bleeding the system
10:11 Hand parking brake
10:12 Fault diagnosis
10:1 Description
All four drum brake units are hydraulically operated by
the brake pedal and the handbrake lever operates the rear
brakes only through a mechanical linkage which normally
requires no separate adjustment (see FIG 10:1).
The brake units are of the internal expanding type with
one leading and one trailing shoe to each brake. A double
ended wheel cylinder expands both shoes into contact
with the drum under hydraulic pressure from the master
cylinder. When the brake pedal pressure is released the
shoes are retracted by means of springs.
The brake pedal is directly coupled to the hydraulic
master cylinder where pressure on the fluid is generated.
This is transmitted to the brakes by a system of metal and
flexible pipes.
The braking units fitted to the new 500 Sedan models
are equipped with a specially designed brake shoe
clearance self-adjustment device which eliminates the
need for manual adjustment of the brake shoe to drum
clearance as is normal practice w i t h a conventional
braking system. Every time the brake pedal is depressed
the self-adjustment device automatically takes up the
excess clearance which may have developed between
the lining and the drum due to normal service wear.
The brake units fitted to the 500 Station wagon model
have a normal brake adjuster which should be used when
F500103 the brake pedal travel becomes excessive. The adjuster
is shown in FIG 10:3.
On later models a dual circuit system is used. It is
described in Section 10:12
10:2 Maintenance
Brake adjustment {Station Wagon)
Jack each wheel in turn after first chocking the remain-
ing three wheels and releasing the handbrake. Depress
the brake pedal so as to force the brake shoes against the
drum and keeping the shoes in this position turn the
adjuster nuts until they contact the shoes and then back
the nuts 20 deg. This will correctly set the shoe to drum
clearance which should be checked for binding by
releasing the brake pedal and ensuring that the road wheel
revolves freely. The operation should then be repeated
on the other wheels. This adjustment will automatically
set the handbrake.
Preventative maintenance:
1 Thoroughly inspect the metal hydraulic fluid lines for
rusting, cracking or flattening and that they are
located away from any sharp edges which could cause
a failure.

FIG 10:9 Brake fluid reservoir
Key to Fig 1 0 : 9 1 Reservoir 2 Strainer 3 Cap, vented
PARKING BRAKE CONTROL CABLE AND SHEATH
.CABLE ADJUSTING NUTS
SHOE OPERATING LEVER
LEVER RETURN SPRING
FIG 10:10 Parking brake control and adjusting mech-
anism at lefthand side rear wheel
Inspect the surfaces of the plungers and the cylinder
bore. If there is any roughness, scoring or corrosion the
assembly should be renewed. Check that the reaction
spring and thrust washers are not corroded or distorted,
renewing any defective parts.
Reassembling wheel cylinders:
Clean the metal parts thoroughly and dry off any
solvent used. The rubber parts should be renewed auto-
matically when servicing the cylinder. Wet the internal
parts w i t h clean brake f l u i d and reassemble them in the
order shown in FIG 10 : 8 .
10810:7 Self-adjusting device
The new 500 Sedan is equipped with a specially
designed brake shoe clearance self-adjusting device
which eliminates all need for manual adjustment during
service.
Operation:
On either side face of the brake shoe rim are placed t w o
friction washers in line with an adjustment slot which is
machined into the brake shoe (see FIG 10:6). The
friction washers are held against the shoe by a pin and
bush screw together through the slot with a strong
spring in between. The hollow pin fits onto the stud in the
brake housing flange. A clearance of .0315 inch between
the pin hole and stud permits the necessary movement of
the shoes to ensure proper braking under normal
operating conditions. On later models the self-adjuster
assembly is held together by a circlip.
When the shoe clearance adjustment is no longer
correct, the braking action will overcome the resistance of
the friction washers and drag along the shoes into contact
with the drum. Once the brake pedal has been released,
the action of the return springs will be weaker than the
friction of the adjustment washers on the shoes and so
the shoes will remain in the new position taken up. As
further wear of the linings occurs the shoes will again
automatically be repositioned by the device.
Inspection and assembly:
During normal brake overhaul all the components of
the self-adjusting device should be thoroughly checked
and any parts badly worn or damaged must be renewed.
Before reassembly it is advisable to check the spring
rating using Fiat tester A.11493 by
compressing the
spring to a height of .374 inch which should give a
corresponding load reading of 97 ± 4.9 Ib. To re-
assemble the device after testing proceed as follows:
1 Place the pin of the self-adjusting device on support
A.54002/2 and insert first the friction washer followed
by the shoe, the second friction washer, the load spring
and the bushings.
2 Fit wrench A.54002/1 onto the support and by
exerting a slight pressure to overcome the spring load
fully tighten the bush onto the pin. Lock the pin and
bushing using a centre punch. Alternatively, fit the
circlip.
3 Install the shoes onto the brake housing flange and
hook up the t w o return springs. Move the shoes out-
wards as far as they will go and release them. Check
that during the return of the shoes the friction washers
have stayed in their new position.
10:8 Removing a flexible hose
Never try to release a flexible hose by turning the ends
w i t h a spanner. The correct procedure is as follows:
Unscrew the metal pipeline union nut from its con-
nection with the hose. Hold the adjacent hexagon on the
hose w i t h a spanner and remove the locknut which
secures the hose to the brackets. The hose can now be
turned without twisting the flexible part, by using a
spanner on the hexagon at the other end.
1
2
3

10:9 Brake fluid reservoir
The reservoir is located in the front compartment to the
side of the fuel tank as shown in FIG 10:9. Should it be
necessary to detach the fluid outlet line from the reservoir
the outlet hole must be blanked off using a tapered
wooden peg of suitable length so that the cap may be
replaced to prevent the ingress of foreign matter into
the reservoir and the absorbtion of moisture, oil or petrol
vapours which would alter the properties of the hydraulic
fluid.
A special filter is fitted into the top of the reservoir
through which all fluid used for topping-up the reservoir
must pass to ensure utmost inner cleanliness of the
hydraulic system.
10:10 Bleeding the system
This is not a routine maintenance operation and is only
necessary if air has entered the hydraulic system because
parts have been dismantled or because the f l u i d level in
the reservoir has dropped so low that air has been drawn
into the main feed pipe to the master cylinders.
1 Fill the reservoir w i t h Fiat 'Blue Label' hydraulic fluid.
During the bleeding operation fluid will be used and
constant topping-up of the supply reservoir will be
needed. If this is not done it is possible for air to enter
the master cylinder main feed pipe which will nullify
the operation and necessitate a fresh start.
2 Attach a length of rubber or plastic tubing to the
bleeder screw on the rear wheel cylinder furthermost
from the master cylinder. Immerse the free end of the
tube in a small volume of hydraulic brake fluid in a
clean jar.
3 Open the bleed screw one turn and get a second
operator to press down slowly on the brake pedal. After
a full stroke let the pedal return without assistance,
pause a moment and repeat the d o w n stroke. At first
there will be air bubbles issuing from the bleed tube,
but when fluid alone is ejected, hold the pedal firmly
down on the floor panel and tighten the bleed screw.
Repeat this operation on the other rear brake and then
repeat the operation on the two front brakes.
4 On completion, top-up the fluid in the reservoir to the
correct level. Discard all dirty fluid. If fluid is perfectly
clean, let it stand for twenty four hours to become
clear of air bubbles before using it again.
10:11 Hand parking brake
Normally with the new 500 Sedan model automatic
brake adjusting device, adjustment of the rear brakes
will take up excessive handbrake travel.
If there is excessive travel on the handbrake of the
Sedan model at any time, or in the case of Station Wagon
model even after the rear brakes have been manually
adjusted, suspect worn brake shoe linings or stretched
handbrake cables. Examine the linings and fit replace-
ment shoes if necessary. Check the action of the hand
parking brake again and if there is still too much travel
before the brakes are applied it is permissible to take up as
follows:
1 It is essential to ensure that the rear shoes are correctly
adjusted as described in Section 10:2.
2 Apply the hand parking brake lever until the pawl
engages with the ratchet at the second notch.
F500
FIG 10:11 An exploded view showing the components of
the tandem master cylinder
3 Jack up the rear of t h e vehicle and place on firmly
based stands.
4 Locate the cable adjusting nuts as shown in FIG
10:10 and adjust these until it is just possible to turn
the road wheels by heavy hand pressure. It is important
that both wheels offer the same resistance to turning
to obtain correctly balanced braking.
5 Return the lever to the OFF position and check that
both wheels are quite free to rotate. If a brake tends to
bind, remove the wheel and brake drum and check
the brake shoe pull-off spring is correctly fitted and
that the lever return spring and operating lever are
functioning correctly. Also check for suspected
seizure of the wheel cylinder. When the fault has
been rectified refit the drum. Readjust and recheck.
Removing the hand parking brake cable:
1 Chock the front wheels and release the handbrake.
Raise t h e rear of the vehicle and place on firmly based
stands.
2 Disconnect the cables from the operating levers on
each rear brake unit. Release each cable from its body
mounted bracket.
3 Inside the car, remove the rear seat and the seat belt
fitting from the floor. As necessary, remove the centre
console and the carpet to give access to the cover plate
on the centre tunnel and remove it.
4 Remove the handbrake lever assembly, detach the
cable compensator and pull the cables through the
holes in the box panel.
5 Reassembly is the reverse procedure to removal.
Ensure t h a t the cable is well lubricated and finally
readjust as previously described.
10:12 The dual circuit braking system
This is used on later model cars. A tandem master
cylinder provides t w o entirely separate hydraulic circuits,
one for the front and one for the rear brakes. The
components of the master cylinder are shown in the
exploded view of FIG 1 0 : 1 1 . The principle of operation is
quite straightforward and easy to understand.
169

FIG 12:1 Detail of right door (early type). Upper arrow
points to vent wing lock handle. Lower arrow points to
window regulator handle
FIG 1 2 : 2 Sedan right side door (later type). Front-hinged.
Door latch is of the triple acting type. Later (pull-out) type
interior lock handles have an escutcheon which is levered
out by means of t w o screwdrivers to expose the handle
pivot pin and spring
Cleaning imitation leather:
To keep the imitation leather clean wash in luke warm
water and a neutral soap applied with a soft cloth. Wipe
clean with a clean moistened cloth with no trace of soap
and finally rub with a clean dry cloth until the original
lustre is restored.
128
Chrome plated parts:
To ensure long life from the chrome plated parts these
should be periodically washed using a cloth dampened
with petrol and dried with a soft cloth. Rub with a cloth
moistened in clean oil especially around the edges of the
components and finally rub using a clean dry cloth until
all traces of oil have been apparently removed.
Glass panels:
The glass panels must be cleaned w i t h a chamois
leather or rag. Take care that no abrasive material is
allowed to be rubbed onto the glass otherwise it will be
scratched.
12:3 Door trim and accessories
The rear-hinged doors have welded upper and lower
hinge halves being joined by a fulcrum pin to the other
half of the hinge which is welded onto the body. Upon
reassembly of a hinge the fulcrum pins must be fitted with
the ball head uppermost. With front-hinged doors the
hinge is bolted to the body pillar.
Check strap (earlier models):
To limit the door opening, a rubber check strap is fixed
by four self-tapping screws of which two are located on
the door and t w o on the body. When a check strap is being
fitted the following points should be noted:
1 Always use sealing compound on the check strap
mounting holes to ensure a moisture t i g h t j o i n t .
2 Insert the screws in the plates and in the strap.
3 Always place a washer on each screw between the
body and the check strap, and also the door and check
strap. Tighten the screws fully.
Weather strip:
A one-piece moulded weather strip is fitted to the door
aperture and fixed by a special adhesive. Should the
weather strip become detached or a new one requiring to
be fitted proceed as follows:
1 Remove the old weather strip as necessary and thor-
oughly clean the door opening flange with petrol,
remove any rust spots and touch in the paint work.
2 Clean the new weather strips of their preservative or
the original from road dirt using petrol and thoroughly
wipe
clean.
3 Apply a coat of adhesive using a brush to the side to be
attached to the body. Allow to dry for the recom-
mended period of time and position the weather strip
on the door opening flange ensuring that it is not
distorted. The joint should be on the bottom side of
the rear end of the door opening. Apply a heavy
pressure on the weather strip starting from the centre
and working towards the ends.
Two rubber lining strips are located on the door flange
and these should be attached using the same procedure
detailed above.
Ensure that the bonding of the rubber weather strips
to both the door opening flange and the door panel is
thoroughly dry before the door is closed, otherwise this
could be the cause of subsequent water ingress.