Note that the pump cannot be dismantled for repair or reconditioning;
if it is faulty, or stops working, it must be renewed. The only
effective test of the pump's condition is described in Section 11 of
this Chapter, but this requires the use of a suitable pressure gauge.
Ensure that the working area is absolutely clean when servicing the
With the pump removed from the fuel tank, unscrew the nuts which clamp
the rubber sleeve to the nylon retaining ring. The retaining ring should
have an alignment mark (a small + symbol embossed on it) next to the
smaller positive terminal; if none can be seen make your own marks
before withdrawing the retaining ring and pulling the pump out of the
rubber sleeve and mesh filter. Note that while it is, of course,
possible merely to pull the filter off the pump lower end, the filter
should be removed and refitted with care so that it is not damaged or
Disengage the filter from the sleeve, noting the alignment marks.
Check the filter for splits or tears; if any are found or if it is a
slack fit on the sleeve, the filter must be renewed. If not, swill it in
high flash-point solvent to remove any particles of dirt.
Carefully clean all components and check for wear or damage; if any is
found the component concerned must be renewed.
Note that the pump has been modified; since the introduction of the 75
models (ie all 1986 on models) a pump is fitted which is manufactured to
tighter tolerances to ensure that the delivery rate remains correct even
at high operating temperatures. This is now supplied as the replacement
part for earlier models also. To prevent the formation of vapour bubbles
which would otherwise interrupt the fuel supply, the new pump is fitted
with a modified mesh filter and rubber sleeve, the filter being fitted
with a separate breather hose.
While the new pump does ensure greater consistency of fuel supply, its
tighter tolerances mean that it is more easily damaged by dirt. To
prevent this, take great care to ensure that the pump components are
kept as clean as possible at all times. Use only lint free cloths for
cleaning purposes and flush out the tank immediately if any dirt or
water are noticed inside it at any time.
On reassembly, check that all components are absolutely clean, then
fit the mesh filter to the rubber sleeve, aligning their marks as shown
in the accompanying photograph. Fit the retainer ring to the rubber
sleeve and tighten the retaining nuts lightly, the ring will fit only
the correct way due to the offset studs and mounting ear cutouts in the
Lubricate the pump body with a smear of fuel or a very small amount of
engine oil, then press it into the rubber sleeve, taking care not to
dislodge the mesh filter, until the locating ribs on the pump body snap
into the grooves in the rubber sleeve. If the pump is a very tight fit,
remove the retainer ring, press the pump into the rubber sleeve and then
refit the ring. When the pump is fully in place, rotate it to align the
retainer ring mark with the pump positive (+ ve) terminal and tighten
the retainer ring nuts securely. Make a final check that the mesh filter
is fully and securely fixed on the rubber sleeve and that the alignment
marks are in line.