1959 FIAT 500 Rear wheel arch

The interior of the car can be heated by the engine
warmed air being ducted into the front compartment and
controlled by a lever on the heating system tunnel.
Engine ignition is by a battery, ignition coil and distribu-
tor which is driven by a gear on the camshaft. The engine
is started by an electric starter motor which is mounted on
the gearbox casing and is controlled by a lever located
behind the gearchange lever.
The complete power unit is mounted by a spring support
at the centre of the rear b o d y crossmember and by t w o
rubber pads mounted laterally to the gearbox.
1 :2 Engine removal (sedan—all versions)
To remove the engine from the car proceed as follows:
Raise t h e rear of t h e car and place on firmly based
stands placed under suitable brackets on the underside
of the body.
Disconnect the battery positive terminal clamp from the
battery terminal post. Release the clip securing the main
petrol pipe to the tank sender unit and ease t h e pipe
from the unit. Drain the oil from the engine sump into
a suitably sized container.
D i s c o n n e c t t h e rear number plate light wire (see
FIG 1 : 6) . Release t h e engine compartment lid check
strap from its slot and separate the lid from the body by
sliding the hinge apart.
Remove the cables attached to the ignition coil, also
to the generator and the starter motor. Remove the
starter motor control tie rod.
Release the oil pressure
indicator cable, the main petrol pipeline at the pump,
the accelerator and starting device controls.
Remove the t w o hoses of the heating and cooling
system which are the input hose to the blower and the
hose for the car heating system. Release and lift out the
engine apron. Remove the starter motor mounting bolts
and carefully lift away the motor.
Using a garage hydraulic jack with suitable cradle (see
FIG 1 : 7) or a rope sling relieve the engine weight
from its mountings. Remove the nuts securing the
gearbox to the engine and the flywheel protection
apron.
Remove the bolts fixing the elastic support to the cross-
member. Remove the rear crossmember mounting nuts
noting that the engine earth cable is held by one
mounting nut and lift away the crossmember.
Carefully ease t h e engine away from the gearbox
ensuring that there is no strain placed on the clutch
shaft. Lower the engine to the floor taking care that no
weight is allowed on any of the attachments. 1
2
3
4
5
6
7
8
1 :3 Engine removal (station wagon)
To remove the engine from the station wagon proceed
as follows:
1 Raise t h e rear of the vehicle and place on firmly based
stands placed under suitable brackets on the underside
of the body.
2 Disconnect the battery positive terminal clamp from
the battery terminal post. Release the clip securing the
main petrol pipe to the tank sender unit and ease the
pipe from the unit. Drain the oil from the engine sump
into a clean dry container of suitable size.
3 H o l d t h e rear door open and secure using string to stop
it swinging to the closed position. Secure the luggage
compartment floor panel in its upright position.
F50013 4 Remove the cables attached to the ignition coil, also
to the generator and starter motor. Remove the starter
motor control tie rod. Release the o i l pressure indicator
cable, the main petrol pipeline at the pump, the accele-
rator and starting device controls. Disconnect the air
filter housing.
5 Remove the hose connecting the car heating system
to the engine cowling. Disconnect the clip holding the
air pipe to the blower and carefully disconnect the pipe
from the blower cowling. Remove the starter motor
mounting bolts and carefully lift away the motor. FIG 1:5 120.000 engine assembly: cross-section view
through a cylinder

3 Check the layshaft and the primary shaft between
centres and using a dial gauge ensure that there is no
distortion. The out of true reading for bearing seats
should be less than .0008 inch. Inspect the splines and
ensure that the side and outerfaces are not indented.
Replace if there are signs of wear. Also inspect the
reverse shaft to ensure that it is perfectly smooth and
not showing signs of pitting or partial seizure.
4 Carefully inspect all gear teeth for signs of excessive
wear or damage. The contact faces must be smooth and
show no signs of indentation marks. Also check that
the backlash between the gears, when correctly
mounted on the surface plate is not greater than .0039
inch. The maximum wear limit is .0079 inch. Check that
the quick engagement front teeth of the second-, third-
and fourth-speed gears are not damaged or excessively
worn. Renew if there are signs of gearchange lever
misuse.
5 Inspect the sliding sleeves and the relevent hubs, ensure
that all the working surfaces are perfectly smooth. The
clearance between the mating parts should not be
greater than .0059 inch. Also inspect the meshing teeth
and ensure that they are in good condition.
6 Check that the gear shifting selector forks are not dis-
torted and that the striker rods freely slide in their seats
in the gearbox casing.
7 Carefully inspect that all the oil seals are in perfect con-
dition and if there is any doubt they should be renewed.
8 Inspect the striker rod locking balls and the safety rollers
and ensure that they slide freely in their seatings. Also
check the ball load spring efficiency and if this shows
signs of weakness then it should be renewed. Any
faults with these items will cause difficulty in engaging
gears or autodisengagement during engine acceleration.
6 : 4 Reassembly—gearbox
To reassemble the components to the gearbox ensure
that all components are thoroughly clean and then pro-
ceed as follows:
1 Press t h e pinion rear roller bearing onto the layshaft.
Install the layshaft in the casing, and at the same time
fit the adjustment shim, the fourth-speed driven gear
together w i t h its bush, the sleeve and hub for third and
fourth gear engagement, the first-speed and reverse
driven gear and the third-speed driven gear with its
hub.
2 Install the front layshaft ballbearing securing the
bearing retainment plate w i t h the screws and finally
lock the screws in position.
3 Insert the primary shaft together with the first, third
and fourth driving gear train in the gearbox housing
and slide t h e rear bearing onto the shaft. Push the
input shaft forward to enable the clutch shaft coupling
to be inserted in t h e rear and to be pulled up the
primary shaft by means of the pin. Do not forget the
retaining ring.
4 Slide the primary shaft backwards so pushing the rear
bearing into its bore. Refit the front bearing onto the
primary shaft.
5 On the layshaft insert the second-speed driven shaft
and bush, the second gear sliding dog sleeve and the
hub. Also insert the second-speed striker rod and the
first-speed fork. Do not forget to fit the safety roller
into its seating.
70
6 Slide the second-speed driving gear onto the primary
shaft. Place the engagement fork on the third- and
fourth-speed engagement sliding sleeve, and insert
the striker rod, lock the relevent fork and fit the safety
roller.
7 Insert the third safety roller and install the reverse shaft
and insert the reverse gear cluster onto it and secure
the shaft by tightening its block bolt. Install the reverse
striker rod w i t h its relevent fork.
8 Now refit the speedometer drive worm gear onto the
layshraft. Tighten the nuts on the primary shaft and the
layshaft, not forgetting to interpose the plain washer
between the speedometer driving worm and the nut,
to a torque wrench setting of 1 8.1 Ib ft to 25.3 Ib ft
(primary shaft) and 28.9 to 36.2 Ib ft (layshaft). It is
recommended that the input shaft and layshaft are
locked together by engaging t w o gears at the same
time. Finally, fit the splitpins.
9 Lock the shifter forks onto their shafts by tightening
their respective bolts and bend up the special locking
plates. Install the three positioning balls and relevant
springs into their bores and refit the cover plate.
10 Install the casing cover together with its relevant
gasket. This will enable correct positioning of the shift
shaft lever so that it engages in the outer ends of the
shifter shafts protruding from the gearbox casing.
11 Install the speedometer drive support on the gearbox
casing and refit the upper gearbox cover.
For subsequent differential operations and adjustments
see Sections 6:6.
6:5 Dismantling—differential and final drive
For the removal of the differential and final drive unit
from the gearbox refer to Section 6:3. To dismantle the
differential assembly
proceed as follows:
1 Remove the retaining ring 2 (see FIG 6 : 7) retaining
the splined sleeve 4 and slide the sleeve off the drive
shaft.
2 Remove t h e retaining covers 7 and the oil boots all
together with the bushes and seals, adjuster ring lock
rings 13, adjuster rings housing 14, and bearing
adjuster and roller bearing outer races.
3 Separate the differential housing halves by unscrewing
and removing the six bolts that keep both the halves and
the crownwheel together. It is advisable to mark the
respective components to ensure correct matching
upon reassembly.
4 Remove the differential pinion shaft retainer ring, also
the differential pinions 10 by removing the shaft and
withdrawing the two axle shafts 1.
5 Remove the differential side gears 6 and relevent thrust
rings 8.
6 Using a press remove the differential bearing inner
races from their seats on the carrier halves.
7 Thoroughly clean all parts and dry using a compressed
air jet.
Inspection:
The components of the differential unit must be
thoroughly inspected for correct operation and to deter-
mine the presence of any wear, damage or other irregulari-
ties. To check the items concerned proceed as follows:
1 Check thoroughly the idle pinion carrier shaft for signs

8 : 7 Hydraulic damper:
Description:
The front and rear shock absorbers are of the telescopic
double acting type. Their dampening action takes place
directly on the suspension without the use of any
intermediate linkage. The shock absorber comprises a
cylindrical body formed by to coaxial tubes 14 and 15
(see FIG 8:11), the inner tube acting as the working
cylinder and the outer one as a casing. The fluid reservoir
being located between the two sections. A third outer
cylinder 13 shields the rod 2 from any road dirt.
On the top the cylinder body is enclosed by a bush 1 1 ,
oil seals 5 and 9 and a housing 4. The rod 2 slides through
the seals 5, the upper end is fixed into the vehicle body
floor and its lower end carries the piston 22 on which
rebound 26 and inlet valves 21 are arranged.
The bottom of the shock absorber is closed by a plug
35 with a threaded shank 36 for the shock absorber to be
mounted onto the suspension unit. The cylinder 15 and
carrier plug 32 is mounted with a compensation valve
30 and a compression valve 33. The piston is provided
with two rows of orifices. The internal row is blanked
underneath by the rebound valve which operates
downwards. The external row is blanked by the inlet
valve which opens upwards. Hydraulic shock absorbers
fitted since March 1959 are provided w i t h a vapour
pocket bleeder from the cylinder exterior. The bleeder
device comprises a capillary
hole 12 interconnecting the
inner cylinder 15 with the upper chamber 10 and also a
passage tube 16 from the upper chamber to the fluid
reservoir. Any vapour pockets in the pressure cylinder
are excluded past the capillary hole 12 into the chamber
10 from which they flow downwards during shock
absorber operation through the passage 16 in a light
fluid stream and up to the top of the reservoir with the
reservoir fluid.
Dismantling and inspection:
Normally during service if a shock absorber becomes
weak in operation then a new unit should be fitted.
Should however, it be necessary for the original unit to
be overhauled proceed as follows:
1 Thoroughly clean the outer casing in petrol and blow
dry using a compressed air jet.
2 Firmly clamp the lower shank of the shock absorber
in a vice and telescope upwards the outer casing and
using Fiat wrench A.56024 unscrew the upper
threaded ring 3 (see FIG 8:11).
3 Remove the shock absorber from the vice and carefully
remove the inner cylinder 15 using a screwdriver
inserted in the cylinder bottom chamfer and remove
the lower plug 32 which carries the compression and
compensation valves.
4 Push the rod i n t o the cylinder 15 and clamp the upper
shank in a vice. Unscrew the plug 29, and carefully
remove the piston 22 together with the inlet and
rebound valves. Withdraw the rod 2 from the cylinder
15 and remove the seal gasket, the housing, and
threaded ring. Thoroughly wash all parts in petrol and
carefully blow dry using a c
ompressed air jet. The
following parts should be inspected as follows.
Check that the inlet, rebound and compensation valve
discs are not deformed or show signs of cracking.
F50093 Inspect the surfaces of the piston, the seal ring and the
compression valve to ensure that they are smooth and
hydraulic fluid tight. Check that the rebound and
compression valve springs and upper seal gasket
springs are not broken or weak. Carefully inspect the
t w o seal gaskets for damage or wear and it is recom-
mended that they are renewed upon reassembly.
Check that the rod and the cylinders show no sign of
deformation and that the air pocket evacuating
passage is not blocked. Also check that the capillary
hole 12 is not blocked. Any parts which show signs
of wear or damage must be renewed.
Reassembly:
Reassembly of the shock absorber is the reverse
procedure to dismantling. Special care must be taken
when refilling the shock absorber w i t h Fiat SA1 oil
otherwise its operating characteristics will be altered.
The hydraulic fluid capacity for the front shock
absorbers is .112 imperial quarts.
The hydraulic capacity for the rear shock absorbers is
.088 imperial quarts. Only Fiat—SA1 oil must be
used.
To insert the components into the shock absorber
body proceed as follows:
1 Mount the piston on the rod, and insert the piston and
rod assembly into the cylinder 15 (see FIG 8:11).
2 Push the piston against the bush 11 and then very
carefully pour the correct amount of hydraulic fluid
up to about j inch from the edge.
3 Press f i t t h e plug 32 and pour the remaining fluid into
the casing 14.
4 Insert the cylinder 15 into the casing 14 and tighten
the upper threaded ring 3.
8 :8 Front suspension assembly and installation
1 Attach Fiat fixture A.66061 to the springs as shown
in FIG 8:12 and load it using the centre screw on the
fixture until the index 'Nuova 500' appears below
the crossbeam lower edge. It is in this position the
spring attains the full static load setting as on the FIG 8:13 Installing right front wheel hub cap by tool
A.66059TOOL
A.66059