The later AUF301 with the Bakelite top (AZX1308 from Burlen-SU with a
slightly different plastic top) do not have a bypass. Not needed as the
max. pressure is only 3,7 psi. A tiny leakage is through the plastic
valves or in the rest of the fuel system after the pump, e.g. float
valves. Damage to parts in the pump is simply not possible with such a
low max. pressure.
I have rebuild well over a hundred SU-pumps by now, most AUF301, and
have at least 20 of those on the shelf. The same pump is also used in
many XK Jaguars, Triumph Stag and Jensen-Healey.
Kees Oudesluijs
Op 18-2-2018 om 18:30 schreef Bob Spidell:
>
> I went through an early (BN2) pump for a different issue--erratic
> pumping--and noticed what appeared to be a small bypass port between
> the brass valves.? I surmised (guessed) that the passageway may be
> there to allow the pump to 'bleed down' when the engine isn't
> running.? Not sure why, but one reason could be that it could be
> detrimental to the diaphragm to be in the 'cocked and loaded' position
> for too long.? Can't say if the later pumps have something similar
> but, as Kees says, the flapper valves probably leak enough to prevent
> this.
>
>
> Bob
>
> --------------------------------
> Bob Spidell - San Jose, CA
>
>> On February 18, 2018 at 10:50 AM Oudesluys <coudesluijs at chello.nl> wrote:
>>
>>
>> It should pump/click every 15s or more. There is always a slight
>> seepage through the plastic valves. They are never 100% leak free. If
>> you hear it pumping more often the chance is that the seat faces of
>> the valves are dirty or corroded. This can usually be remedied by
>> carefully removing the valve assemblies, prying out the plastic
>> valves very prudently, clean them and clean the faces of the bodies.
>> If very corroded the valve assemblies can be renewed. When fitting
>> them back in the pump body use new rubber seals (flat rubber rings).
>> If they are not available you can usually get away with fitting
>> suitable O-rings.
>> If the pump is out clean the contact points with a strip of 2000
>> flower paper.
>> When the points are severely worn, dismantle and rebuild the pump and
>> keep the 3-layer membrane if possible as the new single layer
>> membranes are of a lesser quality. Be very careful not to damage the
>> thin kevlar layer when removing the pump body, separate the layers
>> and rub some talcum powder between the layers very sparingly to
>> create a supple membrane assembly.
>> If you follow the SU instruction to the letter the job of rebuilding
>> is a piece of cake and should not take more than half an hour. Parts
>> are available at the SU dealers. (Google)
>> Kees Oudesluijs
>>
>>
>>
>> Op 18-2-2018 om 8:55 schreef Patrick & Caroline Quinn:
>>>
>>> Greetings
>>>
>>> Well the cavalry arrived and the engine in the BN3 is now running
>>> for the first time in nearly seven years.
>>>
>>> If you recall that despite going by the book the rotor button looked
>>> to be 120 degrees out.
>>>
>>> The solution? Move the geared camshaft/distributor drive about four
>>> teeth, put it all back together, press the solenoid and away it
>>> went. Good oil pressure and lots of gunk out the exhaust and on to
>>> my friend?s E-type. Very pleased!
>>>
>>> Now the next question is why does a SU fuel pump keep pumping
>>> occasionally with the ignition on even when there are no leaks and
>>> the float bowl levels are correct.
>>>
>>> Hoo Roo
>>>
>>> Patrick Quinn
>>>
>>> Blue Mountains, Australia
>>>
>
>
>
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