load capacity FIAT 500 1972 1.G Workshop Manual

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

Checking cut-out:
1 Closing voltage:
This test should be carried out at a temperature of
25°±10°C and the regulator should be connected to a
generator test bed as shown in FIG 11:7. The unit should
be operated under no load conditions for between 15 -
18 minutes with the cover installed and w i t h a voltage of
between 16.5 volts for an initial operating temperature of
15-20°C or 15 volts for an initial operating temperature
of 20-35°C. This will enable thermal stabilization of the
unit to be obtained so that the temperature of both the
cut-out shunt windings and the bymetallic springs
increase due to the heat developed by the windings and
reaches the normal operating setting.
Once thermal stabilization has been obtained the
generator should be restarted and the speed gradually
increased so that immediately the test lamp starts to
glow the voltmeter reading may be taken. This will be
the value of the cut-out contact closing voltage.
2 Reverse current:
This check should be carried out at a temperature range
of between 25°±10°C and it is recommended that it is
performed as soon as possible after the closing voltage
test so that the thermal stabilization remains unaltered.
Connect the regulator as shown in FIG 11:8 and
gradually speed up the generator to 4500 rev/min for
approximately 5 minutes. Ensure that the voltmeter reads
at least 14.5 volts and then gradually reduce the generator
speed carefully watching the movement of the ammeter
needle which should at first indicate a charging current
and then gradually move to zero and then to the other side
of the scale to indicate reverse current value. If the
generator speed is reduced further the reverse current
reading will increase to a given value and then suddenly
fall to zero which will indicate that the cut-out contact
has opened. This limit indicates the maximum reverse
current value which should not, under any circumstances,
exceed 16 amps.
During this test, to obtain the maximum reverse
current possible the reduction in generator speed must
not take more than 10 seconds otherwise the battery
voltage will drop excessively.
Checking voltage regulator:
This test should be carried out w i t h the regulator under
half load and at a temperature of 50°± 3°C. Connect the
regulator as shown in FIG 11:9 and operate the regulator
for approximately 30 minutes by supplying a current half
that of regulated current which is 1 6 ±5 amp. Once the
regulator has been brought to the required temperature
stop the generator and start it again, gradually increasing
the speed to a maximum of 4500 rev/min. Adjust the
rheostat for a generator output corresponding to half load
current of 8 ± 2 amps. When this generator output has
been set the voltage should be 14.2± .3 volts.
Checking current regulator:
Leave the regulator connected as shown in
FIG 11 :10
and this test must be carried out immediately after testing
the half load regulated voltage of the voltage regulator
when connected to a battery. Check that the ammeter
fitted will accommodate a 40 amp deflection: if not a
F500117
FIG 11 :9 Wiring diagram for checking the current and
voltage regulators
Key to Fig 11:9 GR Regulator GN 1.1 2.1 6 G Generator
FIAT D 90.12.16.3 V Voltmeter, 20 V scale (0.5% accuracy)
A Ammeter, 20 A scale (to check voltage regulator) and 40 A
scale (to check current regulator)
B Battery, 50 Ah, fully chargedR Rheostat, 25 A. 3
FIG 11 :10 Wiring diagram for setting the cut-out relay
Key to Fig 11 :10 B 2 V battery B 20 V batteryA Ammeter, 20 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31—51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cut-out shunt winding does not
cause sensible variations in the voltage readings (voltmeter
under no load) S Test lamp, with 2 V, 3 W bulb, to signal
opening and closing of contacts R Rheostat, 4 12
AR Voltage drop resistor, suitable to allow turning on of A withT open and cut-out contacts open
Setting of instruments before inserting the unit: P At
minimum (voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
FIG 11:11 Wiring diagram for setting the voltage and
current regulators
Key to Fig 11 :11 GR Regulator assembly GN 1.12.16
G Generator D 90.12.16.3 V Voltmeter, 20 V scale (0.5%
accuracy) A Ammeter, 20 Amp. scale (for voltage regulator),
or 40 Amp. scale (for current regulator) R Rheostat, 25
Amps., 3 Ohms B 50 Amp/h battery, fully charged I Switch

Checking cut-out:
1 Closing voltage:
This test should be carried out at a temperature of
25°±10°C and the regulator should be connected to a
generator test bed as shown in FIG 11:7. The unit should
be operated under no load conditions for between 15 -
18 minutes with the cover installed and w i t h a voltage of
between 16.5 volts for an initial operating temperature of
15-20°C or 15 volts for an initial operating temperature
of 20-35°C. This will enable thermal stabilization of the
unit to be obtained so that the temperature of both the
cut-out shunt windings and the bymetallic springs
increase due to the heat developed by the windings and
reaches the normal operating setting.
Once thermal stabilization has been obtained the
generator should be restarted and the speed gradually
increased so that immediately the test lamp starts to
glow the voltmeter reading may be taken. This will be
the value of the cut-out contact closing voltage.
2 Reverse current:
This check should be carried out at a temperature range
of between 25°±10°C and it is recommended that it is
performed as soon as possible after the closing voltage
test so that the thermal stabilization remains unaltered.
Connect the regulator as shown in FIG 11:8 and
gradually speed up the generator to 4500 rev/min for
approximately 5 minutes. Ensure that the voltmeter reads
at least 14.5 volts and then gradually reduce the generator
speed carefully watching the movement of the ammeter
needle which should at first indicate a charging current
and then gradually move to zero and then to the other side
of the scale to indicate reverse current value. If the
generator speed is reduced further the reverse current
reading will increase to a given value and then suddenly
fall to zero which will indicate that the cut-out contact
has opened. This limit indicates the maximum reverse
current value which should not, under any circumstances,
exceed 16 amps.
During this test, to obtain the maximum reverse
current possible the reduction in generator speed must
not take more than 10 seconds otherwise the battery
voltage will drop excessively.
Checking voltage regulator:
This test should be carried out w i t h the regulator under
half load and at a temperature of 50°± 3°C. Connect the
regulator as shown in FIG 11:9 and operate the regulator
for approximately 30 minutes by supplying a current half
that of regulated current which is 1 6 ±5 amp. Once the
regulator has been brought to the required temperature
stop the generator and start it again, gradually increasing
the speed to a maximum of 4500 rev/min. Adjust the
rheostat for a generator output corresponding to half load
current of 8 ± 2 amps. When this generator output has
been set the voltage should be 14.2± .3 volts.
Checking current regulator:
Leave the regulator connected as shown in
FIG 11 :10
and this test must be carried out immediately after testing
the half load regulated voltage of the voltage regulator
when connected to a battery. Check that the ammeter
fitted will accommodate a 40 amp deflection: if not a
F500117
FIG 11 :9 Wiring diagram for checking the current and
voltage regulators
Key to Fig 11:9 GR Regulator GN 1.1 2.1 6 G Generator
FIAT D 90.12.16.3 V Voltmeter, 20 V scale (0.5% accuracy)
A Ammeter, 20 A scale (to check voltage regulator) and 40 A
scale (to check current regulator)
B Battery, 50 Ah, fully chargedR Rheostat, 25 A. 3
FIG 11 :10 Wiring diagram for setting the cut-out relay
Key to Fig 11 :10 B 2 V battery B 20 V batteryA Ammeter, 20 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31—51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cut-out shunt winding does not
cause sensible variations in the voltage readings (voltmeter
under no load) S Test lamp, with 2 V, 3 W bulb, to signal
opening and closing of contacts R Rheostat, 4 12
AR Voltage drop resistor, suitable to allow turning on of A withT open and cut-out contacts open
Setting of instruments before inserting the unit: P At
minimum (voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
FIG 11:11 Wiring diagram for setting the voltage and
current regulators
Key to Fig 11 :11 GR Regulator assembly GN 1.12.16
G Generator D 90.12.16.3 V Voltmeter, 20 V scale (0.5%
accuracy) A Ammeter, 20 Amp. scale (for voltage regulator),
or 40 Amp. scale (for current regulator) R Rheostat, 25
Amps., 3 Ohms B 50 Amp/h battery, fully charged I Switch

FIG 11:12 Wiring diagram for setting the cutout relay
Key to Fig 11 :12 B 2 V battery B 20 V battery
A Ammeter, 15 A scale ( 1 % accuracy) V Voltmeter, 20 V
scale (0.5% accuracy), directly connected to terminals 31-51
P Potentiometer for voltage adjustment, having such a capacity
that the current draw of the cutout shunt winding does not cause
sensible variations in the voltage readings (voltmeter under no
load) S Test lamp, with 2 V, 3 W bulb, to signal opening
and closing of contacts R Rheostat, 4 , 1 2 A R Voltagedrop rheostat, suitable to allow turning on of S with T open and
cutout contacts open
Setting of instruments before inserting the unit: P At
minimum (Voltmeter reads zero) T Open R All inserted
(max. resistance) T Open
1
2
3
4
5
6
FIG 11:13 Location of electrical system fuses
Key to Fig 11 :13 1 Fuse N o . 30.2 2 Fuse N o . 30.3
3 Fuse N o . 56.b1 4 Fuse N o . 56.b2 5 Fuse N o . 15.54
6 Fuse N o . 30
meter w i t h a fuller scale deflection of 40 amp must be
substituted. Adjust the rheostat to give maximum
resistance and operate the regulator for approximately
30 minutes with regulator controlled current and 13 volt
supply. The resistor R of the rheostat should be adjusted
until the current is steady whilst the voltage drops. This
will indicate that the unit has reached normal operating
temperature. Stop the generator, restart it and speed up
gradually to 4500 rev/min. Check that the regulated
current value corresponds to the specified value of
1 6± .5 amps. By continually reducing the resistance the
current should remain constant. The voltage however
should decrease to as l o w as 12 volts.
118
Cut-out relay adjustment:
Ascertain the type of regulator fitted and then wire to
the test unit as shown in FIG 11:10 or FIG 11 :12.
Before the unit is assembled to the test bed the instru-
ments should be set as follows:
P - at minimum so that voltmeter reads zero.
T — open.
R - all inserted giving maximum resistance.
T - open.
1 Contact closing voltage:
This test should be carried out at an ambient tempera-
ture of 25°±10°C. Close the switch T and stabilize the
regulator thermally by feeding current into it for approxi-
mately 15 to 18 minutes at 16.5 volts which is obtained
by adjusting P for initial regulator operating temperatures
of between 15°-20°C or at 15 volts for initial operating
temperatures of 20°-35°C. Once the stabilizing of the
regulator has been completed bring the voltage to 12 6±
.2 volts by adjusting P. Adjust the load on the setting
spring by bending the relevant arm until the pilot light S
is extinguished. Reset P to m inimum and again increase
the voltage by P and check that the pilot lamp is extin-
guished at the specified voltage.
2 Reverse current:
This test must be carried out at a temperature of
25°± 10°C and it is recommended that it is carried out as
soon as possible after the closing voltage test so as to
maintain minimum regulator thermal stability. With the
switch T closed bring the voltage to 14.5 volts by
operating P. The contacts of the cut-out should be closed
and the pilot lamp S off. Close T and increase the reverse
current by means of the rheostat R and check that the
pilot lamp S glows as the contacts part. The opening may
also be unsteady which will be indicated by a slight
buzz from the unit. Check the value of the ammeter of the
reverse current causing the opening of the contacts and
this should not exceed 16 amps. If the reading is unstable
or S lights up at the recommended limit reset the reverse
current to the minimum value and repeat the test once
more. Finally open the switches T and T and again
adjust rheostat R and P to the minimum settings.
Voltage regulator adjustment:
This test should be carried out at a temperature of
5 0 ° ±3 ° C . Connect the unit as shown in FIG 11 :11 and
load the voltage regulator adjusting springs by bending
the relevant arm. With the unit at the required test
temperature close 1 start the generator and stabilize
the regulator thermally by feeding a current for 30
minutes at 15 volts, which is obtained by adjusting the
generator speed. The generator should then be stopped,
I opened and the generator restarted and gradually
speeded up to 4500 rev/min. The voltage regulator
spring load adjustment should be set by suitably bending
the relevant adjusting arm and by rheostat R so as to have
a voltage of 14.2±.3 volts and a half load current of
8 ± 2 amps. Finally check the steadiness and accuracy
of the voltage regulator setting by stopping the generator
and restarting after approximately 2 minutes and gradually
speeding up to 4500 rev/min.