should be adopted, dealing with the upper portion of the pump
first:
Place outlet-valve spring retainer (10) in pump upper casting (this
retainer is the small three-legged pressing which retains the outlet-valve
spring), taking care not to distort the legs.
Place valve-plate gasket (13) in position.
The valves should be swilled in clean paraffin before reassembly.
Place the outlet valve (12) on the spring and the inlet valve (12) on the
valve seat located in the upper casting.
Place the valve spring (11) on the centre of the inlet valve, and the valve
plate (14) in position, and then secure with the three screws (15); centre
the inlet valve spring properly in the spring seat in valve plate.
Place the filter gauze (5) in position on top of the casting, and see that
it fits snugly.
Fit the cork washer cover, fibre washer, and retaining screw as described
on page 12 under Cleaning the Filter.
To assemble the lower half of the pump, first assemble the link (25),
packing washers (21), rocker arm (23), and anti-rattle spring (24) in the
body (17).
Insert the rocker-arm pin (20) through the hole in the body, at the
same time engaging the packing washers, link, and rocker arm. Then
spring the retaining clips into the grooves on each end of the rocker-arm
pin.
The rocker-arm pin should be a tap fit in the body, and if due to wear
it is freer than this the ends of the holes in the body should be burred
over slightly.
Note. - The fitting of the rocker-arm pin can be simplified by first
inserting a piece of .240-in. diameter rod through the pin hole in one side
of the body far enough to engage the rocker arm washers and link, and then
pushing the rocker-arm pin in from the opposite side, removing the tem
porary rod as the pin takes up its proper position.
To fit the diaphragm assembly to the pump body:
Place the diaphragm spring (26) in position in the pump body.
Place the diaphragm assembly (27) over the spring, the pull rod being
downwards, and centre the upper end of the spring in the lower protector
washer.
Press downwards on the diaphragm, at the same time turning the
assembly to the left in such a manner that the slots on the pull rod will
engage the fork in the link, ultimately turning the assembly a complete
quarter-turn to the left, which will place the pull rod in the proper working
position in the link and at the same time permit the matching up of the
holes in the diaphragm with those on the pump body flanges.
When first inserting the diaphragm assembly into the pump body,
the locating tab on the outside of the diaphragm (Fig. 13) should be at the
eleven o'clock position. After turning the diaphragm assembly a quarter
of a turn the tab should be at the eight o'clock position.
The two sub-assemblies of the pump are now ready for fitting together,
as follows:
Push the rocker arm (23) towards the pump until the diaphragm
is level with the body flanges.
Place the upper half of the
pump into the proper position,
as shown by the file mark that
was made across the flanges
before dismantling.
Install the cover screws and
lock washers and tighten until
the heads of the screws just
engage the washers.
Release and push the rocker
arm away from the pump in
order to hold the diaphragm at
the top of the stroke, and while
so held tighten the cover screws
diagonally and securely. If
fitted, rocker-arm stop screws
(18) and washer (19) should
be removed for this operation
and refitted afterwards.
The pump is now ready for
testing before it is replaced on
the engine, in the manner
described on page 19.
Refitting the Pump to the
Engine. - Reverse the procedure
outlined for removal from the
engine. Ensure that the rocker
arm is correctly positioned
against the eccentric on the camshaft, as there is a possibility of inadvertently
inserting the rocker arm under the eccentric or to one side, when damage
will result after the pump bolts are tightened. The joint washer between
the pump and the crankcase should be renewed if unsound.
After refitting to the engine the pump should be run for a short time,
and pipe unions and pump examined for the possibility of fuel leakage.
Fig. 13. - Position of Locating Tab.
Reconditioning Pump-valve Seatings
When the valve seatings on A.C. fuel pumps become worn after appre
ciable periods of service they should be trued up. This can conveniently
be done with the aid of a cutter made for the purpose, such as the Buma
valve-seat tool shown in Fig. 14. The tool, with its cutter and flange