1958 FIAT 500 fold seats

CHAPTER 1
THE ENGINE
1 :1
1 :2
1 :3
1 :4
1 :5
1 :6
1 :7
1 :8
1:9
1 :10
1 :11Description
Engine removal (sedan—all versions)
Engine removal (station wagon)
Engine disassembly (sedan—all versions)
Engine disassembly (station wagon)
Cylinder head removal, servicing and
replacement
Timing gear overhaul
Crankcase and cylinders
Piston assembly
Connecting rods
Crankshaft and main bearings
1 :1 Description
The 'New 500' two-cylinder aircooled engine operates
on the four-stroke 'Otto Cycle' and is fitted directly to
the transmission unit which incorporates the rear drive
assembly as shown in FIG 1 :1 and FIG 1 :2.
With the power unit fitted at the rear several advantages
are obtained including better load distribution to the
wheels when the vehicle is loaded, elimination of propeller
shaft reducing the size of centre tunnel and better use of
available space.
The cylinder block comprises t w o cast iron cylinder
barrels w i t h cooling fins. The bottom of the cylinders fit
into machined seats in the aluminium crankcase.
The aluminium crankcase carries eight studs on which
are located the t w o cylinder barrels w i t h the aluminium
cylinder head on the top.
A two bush crankshaft of special cast iron is fitted into
the lower half of the crankcase. The crankshaft is
F5009 provided with a counterweight and is hollow to allow for
lubrication.
The steel connecting rods have thin wall bearing halves
on the big-end, and bronze bushes in the small-end. The
offset piston pin is of steel and retained in the piston by
two circlips.
Light alloy pistons are used and are of the taper-oval-
shaped type with a maximum diameter at the base of the
skirt, along an axis perpendicular to the piston pin. Pistons
are fitted with four rings as follows, one compression at
the top, two standard oil scraper rings and one side slotted
oil scraper ring.
The one-piece aluminium cylinder head is finned to
provide a larger cooling surface and carries the inlet and
exhaust manifolds.
The inlet passages merge into a single centralized
flange onto which is mounted the carburetter. The exhaust
passages run almost parallel to the axis of the engine. 1 :12
1 :13
1 :14
1 :15
1 :16
1 :17
1 :18
1 :19
1 :20
1 :21
1 :22Flywheel and starter ring gear
The oil pump
Lubrication, oil filter, relief valve
Valve timing
Valve stem to rocker clearance
Engine assembly (sedan—all versions)
Engine assembly (station wagon)
Power plant mounting
Adjustment of generator and fan belt drive
Modifications
Fault diagnosis

INTAKEEXHAUSTINTAKEEXHAUST
FIG 1 :18 Main specifications of intake and exhaust valves and valves guides (dimensions in mm)
head. Disconnect the t w o side exhaust manifolds.
Note the spark plug HT cables locations and dis-
connect from spark plugs.
2 Remove the rocker shaft pedestal- and lift away the
rocker gear. Extract the pushrods, making a careful
note of their location. Remove the cylinder head hold
down nuts in the order shown in FIG 1 :44 and using a
puller as shown in FIG 1 :9 lift off the head.
Dismantling the cylinder head:
1 Using Fiat valve spring compressor A.60084 or a uni-
versal spring compressor depress the valve spring as
shown in FIG 1 :14 and lift out the cotters. Release t h e
compressor and withdraw the lock cone, oil shield
(inlet valve only) upper spring cup, valve spring and
lower spring cup. Withdraw the valve from the under-
side of the head.
2 Dismantle the remaining three valve assemblies as
detailed above ensuring that all parts are kept in sets
for correct reassembly.
Inspection and servicing of the cylinder head :
1 Remove all carbon deposits from the combustion
chambers and valve ports using a rotary wire brush or a
set of scrapers.
2 Thoroughly clean the cylinder head and to test for dis-
tortion lightly coat the machined faces with 'Engineers
Blue' or lamp
black and place the cylinder head on a
surface plate. Carefully slide to and fro and any streaks
left behind will indicate a distorted surface. A distorted
head will not make a gas-tight seal with the cylinders
and must be entrusted to an expert for correction or,
in severe cases, renewed.
3 Carefully clean the valve guides as shown in FIG 1:16
using Fiat guide brush A.11417 bis. Should the guides
18Reassembly is the reverse procedure to dismantling.
During assembly utmost cleanliness must be observed as
any abrasive material could find its way to the pistons and
cylinder bores causing unnecessary wear. Check that the
cylinder barrel mating face is clean to ensure correct
gasket sealing.Reassembly of t h e cylinder head:
be worn then they should be removed using a press and
a suitable sized drift. The guides are press fitted with a
pinch fit of .00134 to .00244 inch. To install the guides
use Fiat tool A.601 53 as shown in FIG 1 :17. As the
guides have no stop ring during the press fitting, the
depth of insertion is determined by the Fiat tool. If the
tool is not available take the necessary depth measure-
ments before the old guides are removed. The normal
fit clearance between valve stem and guide is .00087 to
.00217 inch with a maximum wear limit of .0059 inch.
To check this see FIG 1:18.
4 The valve seats should always be reconditioned after
decarbonization. It is suggested that this operation be
left to a local service station with valve seat cutting
equipment. The valve seat angle for both inlet and
exhaust valves is 4 5 ° ± 5'.
5 Inspect the valves for soundness or distortion and if the
clearance between guide and stem is within the manu-
facturers wear tolerance of .0049 inch the valve may
be cleaned using a wire brush and the seating face
ground to an angle of 45°30' ± 5'. This again should
be left to the local service station.
Valve springs:
Thoroughly clean the valve springs of oil deposit and
inspect for cracks. It is advisable to check the free spring
height and if this dimension differs from the original
height, details of which are given in Technical Data, the
spring must be renewed. Any decrease in length indicates
that the spring has weakened.

4 Mixture too weak
5 Water in fuel system
6 Petrol tank vent blocked
7 Incorrect valve clearance
(c) Engine idles badly
1 Check 1 and 6 in (b)
2 Air leak at manifold joints
3 Slow-running jet blocked or out of adjustment
4 Air leak in carburetter
5 Over-rich mixture
6 Worn piston rings
7 Worn valve stems or guides
8 Weak exhaust valve springs
(d) Engine misfires
1 Check 1, 2, 3, 4, 5, 8, 10, 13, 14, 1 5, 16, 17 in (a);
2, 3, 4 and 7 in (b)
2 Weak or broken valve springs
(e) Engine overheats
1 Generator and fan drive belt too loose
2 Shutter or thermostat seized in closed position
(f) Compression low
1 Check 14 and 15 in (a), 6 and 7 in (c) and 2 in (d)
2 Worn piston ring grooves
3 Scored or worn cylinder bores
(g) Engine lacks power
1 Check 3, 10, 1 1 , 13, 14, 15, 16 and 17 in (a), 2, 3, 4
and 7 in (b) 6 and 7 in (c) and 2 in (d). Also check (e)
and (f)
2 Leaking joint washers
3 Fouled sparking plugs
4 Automatic centrifugal advance not operating
(h) Burnt valves or seats
1 Check 14 and 15 in (a), 7 in (b) and 2 in (d). Alsocheck (e)
2 Excessive carbon around valve seat and head
(j) Sticking valves
1 Check 2 in (d)
2 Bent valve stem
3 Scored valve stem or guide
4 Incorrect valve clearance
(k) Excessive cylinder wear
1 Check 11 in (a) and see Chapter 4
2 Lack of oil
3 Dirty oil
4 Piston rings gummed up or broken
5 Badly fitting piston rings
6 Connecting rods bent
(l) Excessive oil consumption
1 Check 6 and 7 in (c) and check (k)
2 Ring gaps too wide
3 Oil return holes in piston choked with carbon
4 Scored cylinders
5 Oil level too high
6 External oil leaks
7 Ineffective valve stem oil seals
(m) Crankshaft and connecting rod bearing failure
1 Check 2 in (k)
2 Restricted oilways
3 Worn journals or crank pins
4 Loose bearing caps
5 Extremely low oil pressure
6 Bent connecting rod
(n) High fuel consumption (see Chapter 2)
(o) Engine vibration
1 Loose generator bolts
2 Blower blade assembly out-of-balance
3 Incorrect clearance for rear engine mounting rubber
F50033

CHAPTER 12
THE BODYWORK
12:1
12:2
12:3
12:4
12:5
12:6
12:7Bodywork finish
Interior and chrome cleaning
Door trim and accessories
Door handles and locks
Removing regulator and door glass
Removing windshield glass
Removing rear side windows12:8
12:9
12:10
12:11
12:12
12:13
12:14Removing rear window glass
Front compartment lid
Engine compartment lid
Folding top
Sun roof
Seats
Interior heater
12:1 Bodywork finish
Large scale repairs to body panels are best left to
expert panel beaters. Even small dents can be tricky, as too
much hammering will stretch the metal and make things
worse instead of better. Filling minor dents and scratches
is probably the best method of restoring the surface. The
touching up of paintwork is well within the powers of
most car owners, particularly as self-spraying cans of
paint in the correct colours are now readily available. It
must be remembered, however, that paint changes colour
w i t h age and it is better to spray a whole wing rather than
try to touch up a small area.
Before spraying it is essential to remove all traces of
wax polish with white spirit. More drastic treatment is
required if silicone polishes have been applied. Use a
primer surfacer or paste stopper according to the amount
of filling required, and when it is dry, rub it down with
400 grade Wet or Dry paper until the surface is smooth
and flush with the surrounding area. Spend time on
getting the best finish as this will control the final effect.
Apply the retouching paint, keeping it wet in the centre
and light and dry round the edges. After a few hours of
drying, use a cutting compound to remove the dry spray
and finish with liquid polish.
F500127
12:2 Interior and chrome cleaning
The cloth upholstery of the seating and the rear
compartment lining must be regularly cleaned to ensure
long life and preserve its attractive appearance. Any dust
or dirt that is blown into the car will settle on the uphol-
stery and will tend to wear the cloth causing an unsightly
appearance. It is recommended that the dust is wiped off
using either a vacuum cleaner or a stiff brush. To remove
ordinary soiling of the upholstery cloth proceed as
follows:
1 Using luke warm water and a neutral soap and a piece
of clean cloth wipe over the upholstery in the direction
of the nap.
2 Repeat the operation using a clean damp cloth and
warm water but no soap.
3 Allow the upholstery cloth to dry, use a stiff brush
against the direction of the upholstery nap to restore
its original fluffy look.
To obtain best results, any stains must be removed as
soon as possible otherwise as time passes they will
become more difficult, if not impossible to remove.
Certain stains require specific solvents and the instruc-
tions must be strictly adhered to.

BOW
FIG 12:17 Sun Roof top in unlatched position
FIG 12:18 Diagrammatic view of car heating system
Key to Fig 12 :18 1 Thermostat controlling shutter 2 Shutter, engine cooling air outlet 3 Lever, heater hand control
4 Warm air outlet slots 5 Demister valve control knobs 6 Windshield demister diffusers
NOTE—The car may be also equipped, optionally, with a heating booster as shown in FIG 12:19
134
4 Rear moulding for the top lining mounting onto the
rear metal panel.
5 Top lining retaining strap which is secured to the front
end of t h e rear metal panel using a bridge bracket.
6 Bracket for strap which hooks up the top lining when
in the folded position.
Dismantling and reassembly is a straightforward
operation providing that careful note is made of the
location of all screws that are removed. To reassemble
it is suggested that the rear metal panel is mounted on
the body shell first. The collapsible top assembly is then
positioned and secured to the rear metal panel using eight
rivets. The top covering should be stretched to the closed
position and secured to both framing side arms to t h e
body shell wells using the special screws. 500F and L
models are similar, but with a single central sun roof latch:
t h e rear metal panel is no longer removable.
12:13 Seats
Front seats:
The front bucket seats comprise a one-piece tubular
frame covered with imitation leather or cloth padded

cushion and back rest. A number of rubber straps are
hooked across the frame under the cushion and in a
sheath covering on the seat back.
The bottom of the front seat frame ends are provided
with sliding guides which run in guide rails attached to
the floor. The sliding guides are pivoted on the frame
tubes to allow for forward tilting of the seats giving better
access to the rear compartment. Two rubber pads
provide cushioning of the seat frame on the guide rails
as shown in FIG 12:11. The control lever for seat
adjustment is fitted in the frame righthand tube to permit
unlocking of the seats so that they may be adjusted to
individual drivers requirements.
Rear seats (Sedan):
The rear seat comprises of a foam rubber cushion and
back. The seat back is cemented to the rear floor and
body shell bulkhead. The rear seat lining is of fabric and
imitation leather. The seat lining is held in place by four
self-tapping screws, t w o of which secure the floor below
the back window and two the lining at the base of t h e
back rest. Included with the seat assembly is a masonite
floor which is fitted below the rear window.
Rear Seat (Station Wagon):
The rear seat back rest is pivoted at the base of its
frame so that it can be folded down to form a load plat-
form surface. In the upright position it is retained in place
by t w o brackets mounted on either side of the body below
the side
windows.
12:14 Interior heater
Description:
Interior heating is accomplished by recirculation of
warm air from the engine cooling system through engine
cowling. Referring to FIG 12:18 a hose conveys warmed
air from the engine cowling to the centre tunnel floor
where warm air flows out through two slots being cut on
the windshield delivery hoses. Air admission can be
adjusted by turning the control lever to the right which
operates the tunnel throttle valve at the rear seat.
The heating system may be fitted with a booster which
comprises a casing on the front exhaust pipe being
connected to the engine cowling and the warmed air
passage tunnel. Warm air flowing to the car interior is
heated to higher temperature than that from the standard
version of heater (see FIG 12:19).
Windshield demisting:
As will be seen from FIG 12:18, t w o air hoses w i t h
throttle valves for airflow control are relayed from a casing
F500135
FIG 12:19 Diagram of booster
Key to Fig 12:19 1 Thermostat controlling shutter
2 Car interior heater booster 3 Hand control unit
in front of the centre of the floor tunnel. Flexible hoses
are connected to two air diffusers which are located on
the instrument panel and parallel to the windshield glass.
When the throttle valves 5 (see FIG 12:18) are operated
through the two control knobs, warmed air is directed
onto the windshield glass so preventing misting, frosting
or icing in adverse weather conditions.
Inspection:
Ensure that t h e lever, the lever spring and butterfly
valve hinge are not distorted. Check that the ducting to
the tunnel as well as the upper and lower hoses are air-
tight which if not, should be renewed.