mirror FIAT 500 1957 1.G Workshop Manual

Cylinder head installation:
To refit the cylinder head proceed as follows:
Place a new cylinder head joint on the cleaned faces of
the cylinder barrels. Insert the rocker pushrod and
lubrication pipe sleeves together with the relevant
gaskets and rings.
Fit the washers and nuts to the studs and tighten to
fingertight.
Tighten the nuts in the order shown in FIG 1 :44 and
FIG 1 :46 to a torque wrench setting of 18.1 Ibft. Reset
the torque wrench to a new setting of 23.9 Ibft and
tighten the nuts once more in the recommended order.
Replace the pushrods in the correct order.
Refit the rocker shaft ensuring correct location of the
lubrication tube to the rocker shaft and replace the
plain and lockwashers. Tighten the nuts to a torque
wrench setting of 15.2 Ibft. Reset the tappet to rocker
clearance adjustment.
Connect the t w o exhaust side manifolds to the cylinder
head. Using new gasket refit the spark plugs and HT
cables. Replace the rocker cover fitted with a new cork
gasket and blower conveyor to the cylinder head
securing screws. Refit the carburetter and reconnect its
fuel line and controls. Refit the air cleaner and elbow
and connect the rocker cover breather pipe (if fitted).
1
2
3
4
5
1 :7 Timing gear overhaul
Camshaft:
The cast iron camshaft is located in the crankcase and is
supported at either end in sets machined directly in the
crankcase. No bushes are used. The camshaft is driven by
a chain from the crankshaft at half engine speed and
operates the overhead valves through tappets, pushrods
and rockers (see
FIG 1 :20).During engine overhaul the camshaft journals and cam
faces should be free of score marks or signs of seizure and
have a bright mirror finish.
The distributor drive gear should be inspected for tooth
wear which if excessive means that the camshaft must be
replaced.
Tappets:
The tappets should be inspected for signs of seizure or
excessive wear. The end surface that is in contact with the
camshaft should be smooth without signs of excessive
wear. Any slight scratches or indentations may be
removed using a very fine oil stone.
Pushrods and sleeves:
The pushrods operate in special axially resilient sleeves
that are compressed on assembly between the cylinder
head and the crankcase. It is through these sleeves that
the engine sump is vented also through which the oil
returning from the cylinder head passes.
Two rubber O-ring seals are fitted to each sleeve to
ensure an oil t i g h t seal between the cylinder head and
crankcase. The sleeves should be checked for distortion
and exact equal length and when refitting new seals must
always be fitted.
The pushrods should be checked for straightness and
the t w o ends that contact the rocker setscrew and the
F50019
The crankcase is an aluminium casting suitably ribbed
to ensure correct air cooling. The main bearing and cam-
shaft bearing bores are machined as also are the tappet 1 :8 Crankcase and cylinders During valve gear overhauls the clearance between the
rocker shaft bore and the rocker must be checked. The
maximum permissable wear between these t w o parts is
.0059 inch. It is recommended that the part which is most
worn be renewed, or in extreme cases both parts. Rocker and rocker shaft: tappet seat must not show any signs of roughness or
excessive wear. 3 Oil shield (for intake valves only) 4 Snap ring
5 Rocker 6 Upper spring cup 7 Valve spring
8 Lower spring cup 9 Pushrod 10 Tappet
11 Oil seal ring 12 Pushrod sleeve 13 Seal ring 1 Intake valve 2 Upper cup lock Key t o Fiq
1 :20 FIG 1:20 Valve, pushrod and tappet assembly FIG 1:19 Camshaft. The arrow points to the lube oil
outlet port

5 Using the graduated sector check that all the valve
timing angles are as detailed in Technical Data.
Readjust the valve stem to rocker arm clearance to the
correct setting.
1:16 Valve stem-to-rocker clearance adjustment
It is important that the clearance between the valve
stem and rocker is kept to the recommended figure
of .0059 inch, measured when the engine is cold.
If the clearance is excessive operating noise will occur
and if less than recommended the valves will stay open
too long which will result in damage to the valve face
and its seating.
Inspect the contacting surfaces for scoring or pitting:
if it is excessive, new parts must be fitted. Also check
the condition of the rocker-to-valve and rocker ball
head-to-pushrod contact surfaces are free from wear or
pitting. The faces must have a mirror finish.
The oilway in the rockers and shaft must be thoroughly
inspected and free from sludge, otherwise lubrication
failure will occur.
The assembly clearance between the rocker arm and
shaft should be .00063 to .00217 inch and the clearance
between the rocker shaft and the shaft support should
be .00020 to .00138 inch with a maximum wear limit of
0039 inch.
Turn the engine until the valves of one cylinder are in
balance, that is, the inlet valve opening and the exhaust
valve closing. The other cylinder will now have both valves
fully closed. Adjust the valves on this second cylinder by
loosening the locknut, and turning the
adjuster as shown in
FIG 1 : 43 to obtain the desired clearance measured with
a feeler gauge. Adjust the clearances on the other cylinder
in the same manner.
1 :17 Engine assembly (sedan — all versions)
To reassemble the engine proceed as follows:
1 Thoroughly clean and dry all the parts, ensure that all
drillings are free from dirt or sludge and place on a
clean dry surface.
2 Carefully install the cylinder-piston-connecting rod
assemblies w i t h new paper gaskets between the
cylinders and crankcase seats.
3 Refit the big-end bearing shells to the connecting
rods, ensuring that they are free from any dirt or
metallic particles. Carefully ease t h e crankshaft into
the crankcase, lubricate the main journals with clean
engine oil, place a new paper gasket between the
supporting member and the flywheel end of the
crankcase. Install the supporting member and bearing
assemblies. Secure the supporting members with the
screws and special toothed washers.
4 Locate the connecting rod big-end half onto the
crankpin journals, liberally lubricate the journals with
fresh engine oil, fit the remaining shell half, matching
bearing end cap and tighten the bearing cap nuts to a
torque wrench setting of 23.9 Ib ft.
5 Inspect the camshaft bearing bores and remove any
burrs w i t h a hand scraper wetted with oil. Carefully
slide in the camshaft ensuring the cam lobes or gear
teeth do not score the front bearing bore.
6 Fit a new timing gear cover paper gasket held in
place w i t h a little grease. Install the outer thrust ring,
F50029 inner thrust ring, shoulder washer and slide on the
camshaft drive sprocket, locking it with the Woodruff
key. Assemble the timing chain and driven sprocket,
ensuring that the timing marks on the sprocket are
indexing as shown in FIG 1 :41. Secure the driven
sprocket with six screws and lockplates and care-
fully bend down the lockplates.
7 Install the timing gear cover, the oil pump, oil pressure
relief valve and seal assembly. Secure w i t h nuts,
special toothed washers and plain washers located
in the same manner as was noted on dismantling.
Locate the oil pump suction horn and secure with the
nuts and toothed washers.
8 Install the flywheel in the same relative position to the
crankshaft as was noted on dismantling. Replace the FIG 1 : 4 3 Adjusting the rocker clearances using the
optional service tools. Refer to Technical Data for the
correct clearance on early and late engines FIG 1 :42 Graduated sector C.673 for valve gear
timing
TIMING MARK

FIG 10:7 Master cylinder section
Key to Fig 10:7 1 Plug and spring seat 2 Body 3 Front wheel brake line duct 4 Plunger return spring
5 Compensating hole 6 Plug 7 Supply duct 8 Fluid inlet hole 9 Plunger 10 Plunger snap ring 11 Boot
12 Pushrod 13 Terminal, stoplight switch 14 Rear wheel brake line duct 15 Holes in floating ring carrier for fluid passage
16 Valve 17 Valve carrier 18 Seal
FIG 10:8 Wheel cylinder section
Key to Fig 10:8 1 Shoe actuating stems 2 Boot
3 Plungers 4 Fluid inlet hole 5 Seal rings
6 and 7 Spring thrust cups and plunger reaction spring
Apply the brakes hard for several minutes and inspect the
master cylinder and hydraulic connections for leaks.
10:6 Wheel cylinder operation
Hydraulic pressure from the master cylinder reaches
the fluid in the wheel cylinders by hydraulic pipes and it
forces the plungers 3 (see FIG 1 0 : 8) apart and through
the plungers the brake shoes operate. In the wheel
cylinders the sealing rings 5 are axially compressed by
the cup 6 under the action of the spring 7. The rings are
under the radial and axial action of hydraulic pressure
so that their sealing efficiency is increased as the
hydraulic pressure increases.
Checking wheel cylinders:
Once the wheel cylinders have been removed from
the brake backplate as previously described remove the
rubber boots 2 (see FIG 10:8) on the ends of the cylinder.
The plungers, brake shoe stems and sealing rings will be
pushed out due to normal spring expansion. Remove the
spring thrust cups and plunger reaction spring.
107F500
Master cylinder reassembly:
Ensure that the metal parts are clean. Dry off any
solvent used for cleaning. Renew all the rubber seals as
a matter of course. Wet the internal parts w i t h clean brake
fluid and reassemble them in the order shown in FIG
10:7.
Refitting the master cylinder:
Carefully locate the master cylinder flange to the body
panel ensuring that the pushrod 12 (see FIG 10:7)
correctly locates in the plunger 9. Secure the master
cylinder flange using the t w o nuts and spring washers.
Refit the hydraulic pipes.
Remove the tapered wooden plug from the reservoir
and bleed the system as described in Section 10:10. Dismantling master cylinder:
1 Refer to FIG 10 :7 and remove the plunger and rubber
boot from the cylinder body.
2 Using a pair of circlip pliers remove the plunger
circlip.
3 Carefully slide off from the inside of the cylinder body
the plunger, plunger seal, valve ring carrier, valve ring
and the reaction spring.
4 Remove the stoplight pressure operated switch.
5 Remove the cylinder body stop plug and upper plug.
6 Carefully inspect the master cylinder inner surface and
plunger outer surface to ensure that they have a mirror-
like finish and that the play between the two parts is
not excessive. Any roughness present on the cylinder
inner surface will necessitate renewing the complete
assembly. Scoring or corrosion of the surface will
quickly damage the rubber seals and can lead to
leakage of fluid and consequent partial or complete
brake failure. Check that the plunger return spring is not
corroded or distorted.

8 Refit the intermediate protection lining ensuring that
it is properly located and well glued. Refit the door
lining panel, key and crank handle.
Door ventilator:
The door ventilator comprises the glass, weather strip
placed between the glass and chromium plated frame,
the chromium plated frame together with pin and bracket
for upper and lower hinging, frame control handle and
lining.
To remove the ventilator glass first drill the upper pivot
pin using a portable electric drill and release the nut and
locknut from the lower pivot bracket. Carefully lift away
the glass.
Reassembly:
To reassemble the ventilator glass proceed as follows:
1 Coat the outer edge of the glass on which the chrome
plated frame must be installed with a 50% solution of
petrol and oil to ensure that the glass can be easily
inserted into the frame.
2 Install the lock handle which is secured to the frame
by means of a screw sunk into the handle body and
t w o corrugated spring washers placed between the
frame and the handle.
3 Before installing the ventilator pane on the door panel
ensure that the metal channels in the front post flanges
at the pane base are firmly located in place and f i t the
rubber weather strip arranging it carefully in its
seating. The weather strip is secured by clips located
on the metal channels.
4 Refit the handle striker plate and secure it to the door
channel by means of t w o self-tapping screws.
5 Insert the lower ventilator swivel on the door panel to
welded bracket. Fit the spring and secure ventilator
assembly through the nut, locknut and plain washer so
that it can, be freely adjusted to any position without
undue effort (see FIG 12:5).
6 Fit the chrome cover on the lower ventilator swivel.
Refit the upper ventilator swivel in the door panel
brackets and clench it using a hammer and a suitably
sized drift against a firm metal block. This will ensure
correct ventilator movement.
FIG 12:8 Adapting windshield weatherstrip. Simply
pull the draw-cord
F500
131 RUBBER BUFFER-HOOD LID LINING
BUMPER
FIG 12:9 Front compartment lid lining and rubber
buffers
HOOD STAY SPRING HOOD STAY HOOD HINGE LOCKING NUTS-
FIG 12:10 Close-up view of hood lid hinge and stay
1 2 : 6 Removing windshield glass
Removal:
To remove the windshield glass carefully push from the
interior of the car against the glass and with the assistance
of a second operator carefully ease the glass away f r o m
the glass aperture as shown in FIG 12:6.
Refitting :
1 Fit the weather strip onto the glass.
2 Insert a draw cord completely around the weather strip
outer lip. Ensure t h a t the cord ends come to the centre
of the lower edge of the glass.
3 Press t h e windshield assembly against the body
opening from the outside as shown in FIG 1 2 : 7 and
then carefully pull the cord ends from the inside so the
overlap of the weatherstrip will locate over the body
opening lip (see FIG 12 : 8).
4 Carefully replace the rear view mirror bulb cable
between the weather strip lip and the body panel from

SEAT RUBBER PAD
SEAT ARTICULATION SUPPORT
SEAT MECHANISM
CONTROL LEVER
SEAT SLIDING GUIDE
SEAT FIXED GUIDE
FIG 12:11 Sedan front seat
42
3
1
FIG 12:12 Sedan rear seat w i t h removable cushion
Key to Fig 12:12 1 Striker plate for triple acting door latch
2 Seat cushion 3 Dowels (two) for seat cushion location
4 Seat back
t h e rear v i e w mirror to the side of the dashboard.
5 Using a special compound sealing gun inject sealer
between weather strip outer lip and body.
12:7 Removing rear side windows
The rear quarter glass panes are located to the body
using the weather strips. To remove the glass simply push
outwards ensuring that a second operator is ready to
catch the glass as the weather strip becomes detached
from the body.
To reassemble the glass pane proceed as directed for
refitting the front windshield. Finally seal as previously
described using sealing compound.
12:8 Removing rear window glass
The rear window glass is removed and replaced in the
same manner as described in Section 12:6 for the
132
FIG 12:13 Centre catch of Sedan and Station Wagon
folding top. Dotted lines show the folding top control
handle in open position removal and replacement of the windshield glass.
Ensure t h a t the weather strip inner groove is thoroughly
filled using correct sealing compound.
1 2 : 9 Front compartment lid
The front compartment lid is hinged at the centre w i t h
the lower half of the hinge welded to the body upper
crossmember. The hinge upper half is secured to the
lower half by nuts and washers which are screwed onto
the lid studs. The compartment lid is kept closed by a
catch as shown in FIG 1 2 : 9 with an additional safety
hook to avoid accidental opening.
The catch release mechanism is controlled by a handle
which is located under the lefthand side of the instrument
panel and connected to the lock by means of a bowden
cable. The cable is arranged inside the front compartment
and the inner wire passes through a bracket and secured
to the catch. A return spring is fitted onto the catch, the
latter pivoting on a locked pin.
A specially shaped weather strip is arranged on the
front and side flange of the front compartment opening.
To refit and renew the weather strip ensure that all the old
bonding compound is removed using a stiff brush.
Spread fresh adhesive to the body shell and carefully
locate and press home the weather strip.
Six rubber bumpers are press fitted into the body shell
and at both ends of the front compartment lid to ensure
correct location and freedom of rattles.
12:10 Engine compartment lid
The opening and closing movement of the lid is con-
trolled by a locking handle. The lid opens downwards and
pivots on two lower hinges. The hinge pin is welded onto
the lid and its socket is welded to the body rear lower
crossmember. To remove the engine compartment lid
proceed as follows:
1 Remove the number plate lamp cable terminal.
2 Unhook the check strap by manipulating the retaining
cross piece.
3 Release the righthand pin self-locking nut and exert
a slight pressure on the righthand side of the lid so
pushing it towards the left.
Reassembly is the reverse procedure to dismantling.