(PD Type)
It is just possible that somewhere one of the very early 848 cc models is still running about with the original SU PD type fuel pump so a few words about this version have been included.
Due to its construction, little servicing can be carried out on the PD pump and this is limited to cleaning the filter and the contact points. If the pump fails, it must be replaced.
The procedure for cleaning the pump filter is included in the TUNE-UP section, as is an illustration of the pump installation.
It should be noted that a peculiarity of the PD pump is that when the ignition is switched on the pump will continue to tick even when the engine is not running and the float chamber of the carburettor is full of petrol.
Contact Points The pump is best removed from its location on the rear sub-frame to inspect the points. Take off the top cover and clean the contact points by drawing a piece of clean paper or card between them. Care should be taken to avoid overstressing the contact blades while doing this. Check that both pairs of contact points make good contact and that the gap between the end of the upper contact blade and its top face is not less than 0.015 in (0.4 mm). No adjustment is provided for the contact points. Also, the contact breaker mechanism is not serviced separately.
SP and AUF 201 Type Later Mini models, up to the adoption of negative earth electrical system in October 1969, all used either the SU SP or AUF 201 type fuel pump. The two types of pump are of similar construction differing only in respect of the pump body which incorporates the inlet and outlet nozzles, filter and fuel valves. The AUF 201 pump is fitted to later models and can be identified by the two plastic nozzles retained by a clamp plate on the end of the pump body.
The three main sources of trouble with these types of pumps are the contact breaker points, fuel valve and diaphragm.
Another common fault is air leakage into the fuel lines, particularly on the inlet side of the pump, causing a constant 'ticking' of the pump without proper fuel delivery when the ignition is switched on.
The pump is best removed from its location at the rear sub-frame for inspection, and this is a straight-forward operation. However, when refitting the pump, ensure that the outlet is located at the top. The outlet must be vertically above the inlet port with the outlet nozzles horizontal.
Contact Points

First remove the end cover and inspect the contact points.
The end cover is normally sealed with tape and a rubber band around the joint and these must be removed. Next remove the nut, Lucar connector and star washer from the end terminal screw and take off the bakelite end cover. The points can then be inspected after slackening the screw securing the spring blade and withdrawing the blade which is slotted at its fixed end. The blade retaining screw also secures the long coil lead and need not be completely removed at this time.
Examine the two sets of contact points for signs of burning or pitting, if either is evident the brass rocker assembly and spring blade must be removed and renewed. Replacement of the rocker assembly will be covered in due course.
Now for inspection of the diaphragm which is located between the coil housing and the pump body. Note or mark the relative positions of the housing and body to ensure correct reassembly. Best to note or mark the position of the earth screw hole in the housing in relation to the pump body.
Remove the six securing screws and separate the pump body from the coil housing and diaphragm. The neoprene diaphragm can now be examined after carefully peeling back the plastic protective sheet. If either the diaphragm or plastic sheet show signs of damage or deterioration, the diaphragm assembly must be renewed. The diaphragm and central spindle are serviced only as a unit and no attempt should be made to separate them.