1971 FIAT 500 mount

After the crankshaft has been reground it is important
that all traces of swarf are removed by constant washing
and then drying with a non-fluffy rag.
The clearance between the main bearings and journals
must be checked before installing the crankshaft in the
engine. It should also serve as a recheck after the
crankshaft has been reground.
Measure the maximum main bearing internal
diameter and the minimum journal diameter using
accurate measuring equipment. The clearance must not
exceed .0039 inch otherwise the journals must be
reground and undersize bearings fitted.
Undersize bearings w i t h .0394 inch stock on the
internal diameter are also supplied unmounted. They
must be press fitted in the supports, the recommended
interference fit being .00039 to .00197 inch. After
pressing the bearing into the support, a hole is drilled in
the bearing in line with the location dowel hole in the
support. The hole is finished with a suitable expanding
reamer, such as Fiat U.0334, and the dowel pressed i n ,
noting that the hollow dowel fits in the flywheel end
support.
The next stage is to heat the assembly in an oven or
oil bath for a period of one hour at 150°C (302°F).
When the assembly has cooled to room temperature,
the bearing is reamed in a lathe to match the crankshaft
journal size.
3
Crankshaft oil seals:
Two inner spring rubber oil seals are located, one in a
special seat in the timing gear cover and the other in the
flywheel end of the crankshaft support and provide oil
tightness. These seals are shown in FIGS 1 :3 and 1 :34.
Whenever the engine is dismantled for overhaul these
seals should be carefully inspected for correct seating and
that the inner seal surface is not worn and that the contact
area is perfect both on the crankshaft and on the fan and
generator drive pulley hub.
Clutch shaft pilot bushing:
A self-lubricating bronze bush is fitted in the end of the
crankshaft as shown in FIG 1 :34 and provides a bearing
for the clutch shaft. Should the bush be worn use Fiat
puller A.40006/1 /2 to remove the worn bush. A new bush
should be fitted using a suitably sized drift.
1:12 Flywheel and starter ring gear
The flywheel should be inspected for wear at the clutch
driven plate contact area. It should be flat and have a
smooth finish.
The ring gear teeth should be cheeked for damage
which if evident, the ring gear must be replaced. To facili-
tate the fitting of a new ring gear on the flywheel, the new
ring gear should be heated in an oil bath to a temperature
of 80°C (176°F). Using a press gently ease the
expanded
ring gear over the flywheel and press fully home.
1:13 The oil pump
Sedan :
A helical-spur gear type oil pump is driven by the cam-
shaft through a front dog drive coupling. The gears are
F50025 To remove the pump from the engine proceed as
follows:Pump removal and reassembly:
Remove the engine rear central support from the timing
gear casing. Remove the filter cover pulley and lift
away the drive belt.
Release the hollow screw attaching the slinger and the
mounting flange of the filter on the crankshaft. Also
release the nuts fixing the timing gear cover to the
crankcase.
Remove the timing gear cover together with the oil
pump assembly and the pressure relief valve.
Lift out the oil pump suction scoop with the filter
screen attached from the sump.
Reassembly of the pump to the engine is the reverse
procedure to dismantling. 1
2
3
4
5 located in a special housing in the timing gear cover and
held in place by a cover plate. The oil pressure relief valve
is mounted on the drive gear shaft guide.
A pump suction scoop fitted with a filter screen is
secured in the crankcase and connects to a duct in the
timing gear case as s h o w n in FIG 1 :36.
2
4
6Key t o Fig 1 :36
Rocker shaft
Ducts, cylinder head oil drain
Oil pressure relief valve
to centrifugal filter
9
with central oil gallery
12Sump cooling air conveyor
indicator sending unitOil filler with vent valve
Line, oil delivery to rocker shaft
Level indicator rod 31
5
7Gear pump
8 Oil duct
Centrifugal oil fitter
1110
Crankshaft
Oil pump intake screen filter
13 Low oil pressure FIG 1:36 Engine lubrication diagram

Drain the oil sump to ensure that the oil does not syphon
out. Thoroughly clean the area around the pump body
(see FIG 1 :37).
Remove the end cover plate by releasing the retaining
bolts and washers. Carefully ease t h e driven gear down-
wards followed by the driving gear and shaft
Clean all parts removed and blow clean using a com-
pressed air jet. Inspect the timing gear cover pump area
for cracks or distortion. Check that the inner duct for oil
delivery to the pump is clear of obstruction. If in doubt
remove the drain plug and filler cap and use a com-
pressed air j e t to clean the passage.
Check the gear teeth for damage or excessive wear,
ensure that the drive gear is firmly attached to its spindle
and that the end cover plate is not badly scored or pitted.
Fit new parts as necessary.
Reassembly is the reverse procedure to dismantling,
taking care that all parts are assembled clean and the
end cover plate seating correctly with a new gasket. 5 43 21
1:14 Lubrication, oil filter, relief valve
Description :
The engine is pressure lubricated through a gear type
pump which is incorporated in the timing gear cover and
driven from the camshaft by dogs or gears. The lubrication
circuits are shown in FIGS 1 :36 and 1 : 37.
The pump draws oil from the sump through a suction
horn fitted with a filter screen which is fixed to the crank-
case by a d u c t in t h e timing gear cover. This
supplies oil
to the pump.
Oil passes f r o m the camshaft rear seat o n t o t h e crank-
shaft rear support where it flows into an adjacent chamber.
From here the o i l flows through ducts in the crankshaft
from end to the centrifugal oil filter. The centrifugal filter,
which also acts as a pulley for the generator and blower
drive, rotates w i t h the crankshaft.
Oil from the filter enters a passage in the crankshaft,
where it lubricates the main and connecting rod bearings
and passes f r o m a special groove in the front main
bearing and ducting in the crankcase into which is
inserted the oil pressure warning sender unit, and also
the delivery pipe for oil to the overhead valve gear.
The pushrod sleeves provide the return path for the oil
from the cylinder head and delivers oil to the tappet gear
and the camshaft cams. The tappets are suitably drilled
to allow correct circulation of the oil. The tappets are
located in t w o casting cavities, one of which com-
municates w i t h the timing gear housing and the other
one to the crankshaft front drain support drain.
The oil pressure is regulated by a pressure relief valve 5
(see FIG 1 : 3 8) mounted at the rear end of t h e camshaft.
It comprises a hubbed disc which slides on a guide 6 of
the oil pump drive shaft 7. Under spring load 9 the valve
disc circumferentially closes an annular chamber which
communicates w i t h the lubrication circuit. Excessive o i l
pressure causes the disc to uncover the chamber.
Centrifugal oil filter:
The oil filter is of the centrifugal type comprising of
two flanges and an oil slinger. The filter is attached to the
rear end o f t h e c r a n k s h a f t a s s h o w n i n FIG 1 :38. The
outside diameter of the oil slinger (see FIG 1 :39) is
smaller in diameter than that of the flanges but of such a
F50027
Key to Fig 1:39 1 Drive pulley 2 Rotor hub
3 Seal ring 4 Oil slinger 5 Lockplate
6 Hub-to-crankshaft hollow screw 7, 8, 9 Pulley-to-hub
mounting screws, toothed washers and plain washers FIG 1:39 Centrifugal oil filter components Key to Fig 1 :38 Suction scoop 2 Hole in crankcase
3 Duct in timing sprocket cover 4 Timing sprocket cover
5 Oil pressure relief valve 6 Drive shaft guide and oil
pump cover 7 Oil pump driving gear shaft 8 Camshaft
9 Oil pressure relief valve spring FIG 1:38 Engine longitudinal section through oil pump

FIG 1 :40 Engine detail showing lube oil passages
Key to Fig 1 :40 1 Splines in crankshaft for oil passage
to filter 2 Oil inlet into circuit from filter 3 Hole for
oil passage to main bearing
FIG 1 : 4 1 Timing marks on sprockets. On later cars the
crankshaft key way is on the underside
size that centrifugal force does not sling oil into the area
where the foreign matter is collected. The outer flange
inner face has radial vanes on its face which retain the
foreign matter and the oil is conveyed to the centre of
the filter.
The oil to be filtered issues from the side splines 1
(see FIG 1 :40) of the crankshaft and is forced by the
slinger to the periphery of the filter where it is cleaned and
returns to the centre of the filter and into the crankshaft
drilling 2. The inner flange or hub and the slinger are
secured to the crankshaft by a special hollow screw 6 as
shown in FIG 1 :39, the outer flange is attached to the
hub by six screws.
28
If the camshaft has been disconnected from the crank-
shaft for any service operation the valve gear will have to
be retimed and to do this proceed as follows:
1 Turn the crankshaft until the reference line on its
sprocket is pointing towards the camshaft as shown in
FIG 1 :41.
2 Turn the camshaft until the reference dot on its
sprocket registers w i t h the crankshaft sprocket. Leave
the shafts undisturbed and carefully mount the chain.
Should it be necessary to check the valve timing and
sprocket marks, proceed as follows:
1 Fit Fiat C.673 tool as shown in FIG 1 :42.
2 Temporarily adjust the valve stem-to-rocker arm
clearance of cylinder No. 1 at .01 77 inch for the inlet
valve and .01 50 inch for the exhaust valve (Model 500
engine) or at .01 54 inch for both valves (Model 500
sports).
3 Rotate the crankshaft and set the flywheel timing mark
at 'O' on the graduated sector. Check that the sprocket
marks are correctly lined up in this position.
If the engine is being assembled, to install the driven
gear, proceed as follows:
1 Set the timing mark on the drive sprocket towards the
centre of the camshaft.
2 Position the driven sprocket on the camshaft mounting
flange with four screw holes in line and tighten two
mounting screws only.
3 Rotate the camshaft until the driven sprocket mark
registers w i t h the reference line on the drive sprocket.
4 Remove the driven sprocket without moving the
camshaft. Install the timing chain and replace the
driven sprocket. Tighten the four screws to a torque
wrench setting of 6.5 Ib ft.
1:15 Valve timing
The oil pressure indicator sender unit is located on the
righthand side of the cylinder block and is connected to
an indicator light in the instrument cluster on the dash-
board.
The red indicator lights only when the ignition is
switched on and goes out when o i l pressure has built
up to between 8.5 and 14 Ib/sq in.
Should an accidental shortcircuit occur in the oil
pressure indicator circuit, the sender unit may be damaged
so the cause must be traced and rectified before the unit
is renewed.
Oil pressure indicator sender unit:
To ensure a reliable lubrication system there must be
no oil leaks from the gasket between the outer and inner
flanges. Every t i m e t h e engine is overhauled the filter
must be dismantled, cleaned and new gaskets fitted.
To clean the filter, remove the six screws and washers
and separate the drive pulley and hub. Carefully scrape
the inner surfaces to remove all sludge.
Upon reassembly the filter to crankshaft hollow
mounting screws must be tightened to a torque wrench
setting of 1 08.5 Ib ft. The cover to mounting flange screws
must be tightened to a torque wrench setting of 5.8 Ibft.
Cleaning and inspection:
A groove is machined on the outer flange periphery to
form a pulley for the generator and blower drive belt.

FIG 1 :44 Cylinder head h o ld-down nuts tightening
sequence. 500 Sedan
TIMING CHAIN ENDCYLINDER No. 1 CYLINDER No. 2 FLYWHEEL END
CAMSHAFT
EXPANSION SLOT C/ROD NUMBERROTATION DIRECTION
FIG 1 :45 The correct position of connecting rod-
piston assembly on engine 120.000
30
screws and together with new lockplates tighten to a
torque wrench setting of 23.1 Ib ft. Bend down the
lockplates.
9 Slide the centrifugal oil filter mounting flange, the
oil slinger and the mounting screw together with its
lockplates onto the crankshaft and tighten the screw
to a torque wrench setting of 108.5 Ib ft. Bend down
the lockplate.
10 Assemble the clutch assembly to the flywheel and
using Fiat pilot A.62023 centralize the driven plate
to the pressure plate assembly. Secure the pressure
plate assembly using screws and toothed washers.
11 Fit new oil pan cork gasket, if necessary using a little
grease to hold in position and carefully fit the oil pan
securing with screws, toothed washers and lock-
plates. Bend down the lockplates onto the screw
heads.
12 Fit the oil cooling air conveyor on the oil pan and
secure with screws and toothed washers.
13 Carefully turn the engine over and fit the centrifugal
filter mounting flange rubber seal. Fit the oil filter
cover and secure with screws together with plain and
toothed washers to a torque wrench setting of
5.8
Ib ft.
14 Ensure t h e faces of the cylinder head and cylinders
are free from dirt and oil and carefully slide the
cylinder head gasket over the studs ensuring that it
is the correct way up. Insert the tappets in the same
order to removal together with the sleeves, pushrods,
oil delivery line to the rocker arm shaft and the casing
with its seal ring.
15 Thoroughly inspect the cylinder head to ensure that
it has been correctly reassembled, carefully slide it
over the studs and secure using the four cap nuts
internally and four standard nuts and plain washers
externally. Tighten the nuts in the order as shown in
FIG 1 :44 or 1 :46 to a torque wrench setting of
23.9 Ib ft.
16 Fit the rocker arm shaft and arm assembly together
with the two supports. Tighten the supports using
screws, plain and toothed washers to a torque
wrench setting of 15.2Ibft. Adjust the tappet-to-
rocker clearance as detailed in Section 1 :16.
17 Temporarily plug the intake duct hole to ensure that
no foreign matter finds its way into the engine.
Install the spark plugs having ensured that they are
clean and correctly adjusted.
18 Reassemble the engine cowling and air
exhaust
throttle valve assembly which should be secured on
the top side using t w o nuts, t w o plain washers and
two toothed washers, on the underside with two
screws and t w o toothed washers, and centrally using
one screw and one spring washer.
19 Fit the toothed washers on the end of the spark plug
electrode and tighten the terminals together with the
special rubber boots.
20 Refit the fan, generator and ground cable assembly
and secure the crankcase, also the warmed air intake
shrouding. Finally tighten the generator to fan nuts.
21 Fit both lower exhaust silencer mounting brackets
onto the crankcase but do not tighten fully. Fit the
air conveyor and secure to the engine cowling using
six screws, six toothed washers and one nut together
with a toothed washer. Join together the t w o

sections of the air conveyor securing with seven
screws, seven toothed washers and five nuts.
22 Slide the fuel pump control rod into its seating,
assemble the insulator between oil wetted graphite
gaskets and fit the pump to the crankcase using nuts
and toothed washers.
23 Fit the air conveyor cover complete with the accelera-
tor control relay lever and rod. Secure using eight
mounting screws, eight toothed washers, eight plain
washers and eight nuts. Fit the fuel line retaining clip
which is secured by one of the air conveyor upper
screws. Install the generator and fan drive pulley
having first placed four adjusting rings between the
pulley halves and the thrust ring on the outside.
Secure the pulley to generator shaft using three
screws and three toothed washers. Fit the generator
fan drive belt.
24 Refit the carburetter having first positioned the
bakelite heat shield between the t w o oil moistened
graphite gaskets. Secure the carburetter using t w o
copper washers and t w o self-locking nuts. Fit the
exhaust silencer and secure to the exhaust manifolds
with nuts and spring washers. Place the t w o graphite
gaskets between the manifold joints. Fit both exhaust
silencer upper mounting brackets and secure them
on the top side to the brackets already in place w i t h
nuts and toothed washers on the bottom side w i t h
screws and toothed washers.
25 Carefully position the distributor at a 10 deg advance
setting and secure w i t h a
nut, plain washer and
spring washer. Fit the fuel pump to carburetter line
complete w i t h mounting bracket rubber lining and
secure the line with two clamps. If difficulty is
experienced in positioning the fuel line into the pump
or carburetter funnels it is suggested that the line
ends should be heated in hot water and thoroughly
dried before installing.
26 Install the air cleaner elbow and rubber hose assembly
on the top of the carburetter using a graphite gasket
in between and secure w i t h nuts, plain washers and
spring washers. Carefully position the air cleaner, line
and hose assembly and connect it to the elbow.
Secure the cleaner to air conveyor cover using screws
and toothed washers.
27 Fit the spark plug cables complete with the rubber
grommet for cable mounting bracket on engine
cowling and connect the cables to the distributor
and spark plugs. Fit the oil pressure gauge sender
unit together w i t h its sealing washer.
28 Install the cylinder head cover and oil breather pipe
assembly w i t h a cork gasket inserted between.
Secure w i t h self-locking nuts and fibre washers.
Connect the accelerator control relay lever rod to the
carburetter and secure with the clip.
29 Fill the oil pan with the correct grade and quantity of
oil, insert the dipstick and the engine is ready for
refitting.
1:18 Engine assembly (station wagon)
Reassembly of this engine is straightforward as it is
the reverse procedure to dismantling. It is recommended
that Sections 1 :5 and 1 :17 are studied as the assembly
technique is similar for both the horizontal and vertical
F50031 cylinder engines. The following points should however
be noted:
1 Refer to FIG 1 :45 for the correct positioning of the
connecting rod-piston assembly on the 120.000
engine.
2 The sequence of tightening the cylinder head nuts is
different, the new order being given in FIG 1 :46.
Key to Fig 1 :47 1 Suspension arm 2 Screw,
rubber pad to bracket 3 Bracket-to-engine nut
4 Nut, arm to bracket 5 Arm bracket 6 Spring
7 Arm pin-to-support nut 8 Screws, pin to support
9 Pin arm to supportFIG 1 :47 Power plant rear suspension FIG 1:46 Cylinder head stud nut tightening sequence.
500 D. F and L Sedan and Station Wagon

FIG 1 :48 Power plant front support cross-section
FIG 1 :49 Checking the generator and blower drive
belt tension
1 :19 Power plant mountings
The combined power and transmission unit is elastic-
ally mounted on two supports.
The front of the unit rests on a crossmember which is
secured under the car floor through two rubber block
mountings that are bolted to the gearbox casing as
shown in FIG 1 :48. The position of the rubber blocks
on the crossmember is adjustable so that the assembly
can be correctly aligned.
W i t h t h e rear of the unit the engine crankcase is sprung
to the b o d y rear crossmember through an articulated
swinging arm that compresses a coil spring as shown in
FIGS 1 :47 and 1 :49. A rubber bump pad is mounted
inside the spring to give a progressive action.
Whenever the power and transmission unit is being
serviced the condition of the mountings should be
checked and any worn or damaged parts renewed.
1 :20 Adjustment of generator and fan drive belt
The centrifugal oil filter cover/pulley on the crankshaft
transmits the drive through a V-belt to the generator and
centrifugal fan pulley.
32
(b) Engine stalls
1 Check 1, 2, 3, 4, 10, 1 1 , 12, 13, 14 and 15 in (a)
2 Sparking plugs defective or gaps incorrect
3 Retarded ignition 1 Defective coil
2 Faulty distributor capacitor (condenser)
3 Dirty, pitted or incorrectly set contact breaker points
4 Ignition wires loose or insulation faulty
5 Water on sparking plug leads
6 Corrosion of battery terminals or battery discharged
7 Faulty or jammed starter
8 Sparking plug leads wrongly connected
9 Vapour lock in fuel pipes
10 Defective fuel pump
11 Overchoking
12 Underchoking
13 Blocked petrol filter or carburetter jets
14 Leaking valves
15 Sticking valves
16 Valve timing incorrect
17 Ignition timing incorrect
(a) Engine will not start 1 :22 Fault diagnosis
Since its introduction the Fiat new 5 0 0 model has
been continually developed. The main modifications that
have been made are as follows:
1 Heating system safety device
2 Recirculation device for the blow-by gases
3 Cylinder head modified to incorporate item 1
4 Double valve springs fitted
5 Cylinder barrels modified to incorporate item 1
6 Flywheel modified to incorporate new type diaphragm
spring clutch mounting
7 Larger air cleaner container.
Details of these modifications are to be found in the
relevant sections if they necessitate a change in service
overhaul procedure. Other information is to be found in
Technical Data.
1 :21 Modifications
When the V-belt has been correctly adjusted the belt
should sag 13/32 inch under a hand pressure of about 22 lb
as shown in FIG 1 : 4 9.
Should the belt be too slack the generator and
centrifugal fan will not operate at the correct speed
causing overheating and a discharged battery. Also the
belt will slip causing rapid wear of the belt. Conversely
if the belt is too tight excessive loading will be placed
on the generator bearings causing excessive bearing
wear and noisy operation.
To adjust the belt tension proceed as follows:
1 Remove the three nuts ' B ' (see FIG 1 :49) on the
generator pulley and this will split the pulley into two
parts between which are spacer rings.
2 The tension of the belt is increased or decreased by
either reducing or increasing the number of spacers.
3 Place the spacer rings removed from between the
pulley halves on the pulley outer face so that the rings
may be re-inserted when fitting a new belt.
4 Tighten the three nuts to a torque wrench setting of
14.5
lb ft.
Key to Fig 1 :49 A Normal give-in: about 13/32 inch under
a 22 Ib pressure B Nuts securing the pulley halves with
spacer rings

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

CONTROL ROCKER FROM TANK TO CARBURETOR
FIG 2 : 1 Fuel pump. Arrows point to fuel inlet and outlet
FIG 2 : 2 Fuel pump components
KeytoFig2:2 1 Cover screw 2 Screw gasket3 Cover gasket 4 Cover 5 Upper body
6 Spring for inlet valve 7 Inlet valve 8 Outlet valve
9 Spring for outlet valve 10 Plate gasket 11 Plate screws
12 Valve retaining plate 13 Filter gauze 14 Diaphragm,
complete with tie rod 15 Return spring 16 Spring
thrust cup 17 Felt 18 Washer for felt
1 9 Connection screws 20 Lower body 21 Rocker
22, 24 Gaskets 23 Insulating pad 25 Pump control
pushrod
36
FIG 2 : 3 Fuel pump and control pushrod
FUELPUMP CONTROLPUSHROD
INSULATING
PAD
FUEL PUMP
A l l 500 Sedans are equipped with Weber type 26. IMB
carburetters w i t h detail differences only between the
models. The carburetter is of a downdraft single choke 2 : 6 Carburetter operation and adjustment,
Weber 26.IMB Carefully slide the pump control pushrod into the
crankcase, assemble the t w o gaskets w i t h the insulating
pad in between and slide over the pump retaining studs.
Ease t h e p u m p towards the crankcase ensuring the push-
rod locates correctly in the rocker end. Finally tighten the
two retaining nuts and spring washers. Installation:Ensure t h a t all parts are clean and dry. Assembling is the
reverse procedure of dismantling. Lubricate the rocker
lever and pin before placing them in the lower body. 2 : 5 Reassembly, installation and adjustment 1 Refer to FIG 2 : 2 and remove the cover mounting
screw 1 and washer 2. Lift off cover 4 and filter 13.
Mark the relative position of the two halves of the pump
body. Remove the pump bodies interlocking screws 19
and separate the upper half from the lower half of the
body.
2 Push down the centre of the diaphragm assembly 14
and rotate through 90 deg. to release diaphragm from
the rocker 2 1 . Lift out diaphragm and spring 15.
3 Release the t w o valve assemblies in the upper body by
removing the valve retaining plate locking screws 1 1 ,
and lifting out the plate 12, gasket 10, valve springs 6
and 9, and valves 7 and 8.
4 Using a pin punch remove the rocker pivot pin together
w i t h the t w o washers and carefully lift away rocker and
reaction spring.
5 Thoroughly wash all components in petrol and
blow
dry with compressed air or a foot pump. Inspect the
valves 7 and 8 for evidence of damage and valve springs
6 and 9 for weakness or cracks. Check to see that the
diaphragm reaction spring and rocker are not distorted
or unserviceable. Generally inspect all parts for cracks,
distortion and the diaphragm for stiffness and also the
rocker and pin for wear. Dismantling: