Morris Minor Owners Club

My SU pump has given some trouble on occasion and I'm wondering if I should fit a replacement. Or potentially do a rebuild. This (link below) is available at much less than a new genuine SU pump, which is roughly £200 from ESM.

https://ebay.us/m/5uMQ1N

It says it's suitable for classics like the Minor and Mini.There are other very similar looking pumps on there too, at similar prices.

Could it be suitable? I'm not sure how the connection to the metal inlet pipe from the tank would work for starters. And I've seen the SU referred to as a low pressure 'suck' pump. These alternatives seem to be 6psi. Is that too much?

Please share your thoughts.

Facet pumps tick continuously and loudly. The rated pressure of the SU AUA66 is 1.5 psi so at 6 psi I suspect that cheap pump will cause the float bowl to flood and leak.

If you don’t want to overhaul your pump yourself then why not buy a refurbished pump from club spares? See Minor Matters club spares adverts. Then you could refurbish your existing pump at your leisure and have a spare.

Stephen

Don't do it it's crap leaking badly after a few days, you will need a pressure regulator, I bought a new S U pump directly from S U British built works brilliantly

Thank you both.
I shall contact the club spares tomorrow.

A pump cannot be suitable for a Mini AND a Minor. One pushes petrol from the tank, the other sucks it to the engine bay. Buy cheap and get rubbish. You can't beat the correct SU pump.

Do both.
Buy a new S.U. pump and refurbish the old one, which you can sell to offset the cost if required.
Nothing looks worse than an incorrect replacement part in full view when the bonnet is lifted, (which the fuel pump is) in my opinion.
My car came with a working plastic bright red electronic pump made in New Zealand, I have no doubt it would work ad nauseum, but it looked completely out of place.
I have kept it just in case, but my new S.U. pump has been on for 14 years and has yet to fail.
And it looks right.

Yes, a new SU and refurb the old pump when you have time is a good solution. That's what I did and have kept the refurb one in the boot. Haven't needed it, but its good to know its there........

I'd bought a "compatible" Hardi pump from ESM, as a spare.
But several forum members have mentioned that it's too high a pressure for Minors.
Plus it doesn't have an integral input filter.
I make cleaning this filter part of the annual service, along with giving its points a gentle clean (in situ).

Thanks for the advice everyone.
Looking at the Club spares, I was surprised to see pumps for E10 petrol and non-E10. The diaphragm I guess?

KevinB wrote: ↑Mon Mar 02, 2026 12:43 pm Thanks for the advice everyone.
Looking at the Club spares, I was surprised to see pumps for E10 petrol and non-E10. The diaphragm I guess?

Yes it can only really be the diaphragm as there is no rubber anywhere else. SU replacement diaphragms on sale now just say "suitable for all modern fuels". Perhaps club spares used up old spares.

Stephen

svenedin wrote: ↑Mon Mar 02, 2026 1:06 pm

KevinB wrote: ↑Mon Mar 02, 2026 12:43 pm Thanks for the advice everyone.
Looking at the Club spares, I was surprised to see pumps for E10 petrol and non-E10. The diaphragm I guess?

Yes it can only really be the diaphragm as there is no rubber anywhere else. SU replacement diaphragms on sale now just say "suitable for all modern fuels". Perhaps club spares used up old spares.

Stephen

Undoubtedly the diaphragm.
Some of the Club Spares overhauled ones have probably been in stock since long before E10.
I've got 4 or 5 old SU Pumps, brought cheap from ebay, which I'll get around to overhauling some time....
The original diaphragms in them are pretty much all a combination of rubber and clear plastic on the fuel side.
You can see where it's wrinkled with the fuel in contact.
.

Well .. I've decided I should learn how to rebuild my fuel pump. Not done that before, though I have rebuilt SU carbs in the past (decades ago).

So have ordered a SU pump rebuild kit. Quite pricey these days. Hope it has instructions!

I will let you know how it goes.

Kevin

KevinB wrote: ↑Mon Mar 02, 2026 9:50 pm Well .. I've decided I should learn how to rebuild my fuel pump. Not done that before, though I have rebuilt SU carbs in the past (decades ago).

So have ordered a SU pump rebuild kit. Quite pricey these days. Hope it has instructions!

I will let you know how it goes.

Kevin

This may help. Good luck! https://board.mmoc.org.uk/viewtopic.php ... t=Su+AUA66

Stephen

Thank you Stephen!
Kevin

Can Stephen confirm that the Rebuild kit (eg from ESM) contains all the bits mentioned in his earlier post.

mike1864 wrote: ↑Tue Mar 03, 2026 2:11 pm Can Stephen confirm that the Rebuild kit (eg from ESM) contains all the bits mentioned in his earlier post.

Yes the kit contains everything you need for a rebuild. You just have to be aware that there a two kits available. One for pumps pre-1985 and one for post-1985.

Stephen

Thanks, Stephen. How do you distinguish between those two vintages? And can I assume they are all polarity independent?

These parts have arrived, plus others of course.
Supposed to be for a pre-1985 pump, I think the new diaphragm is? (looking at Stephen's thread)..
https://board.mmoc.org.uk/viewtopic.php ... t=Su+AUA66

I smiled when checking the workshop manual - it says the old, dirty pump should be cleaned with caustic soda, followed by strong nitric acid. Not sure how easy they are to buy, these days?

Not started the dismantling yet.

mike1864 wrote: ↑Tue Mar 03, 2026 2:53 pm Thanks, Stephen. How do you distinguish between those two vintages? And can I assume they are all polarity independent?

They can be distinguished by the size of the BA earth screw on the side of the pump. Pre-1985 2BA; Post-1985 4BA. If not sure about BA sizes have a look at the pictures on my thread. 2BA is bigger than 4BA.

Yes, the kit is for a points pump and it does not matter what the polarity is. A Transil is included in the kit. This acts as a spark arrestor and it is not polarity sensitive. However, it is not that easy to fit under the standard cap. You must take care bending the tails on the Transil or they can snap off and when fitted it must not impede the operation of the points. Do not bend the tails too close to the body of the component. I would suggest it is far easier to buy a new cap either of the stepped black bakelite type or the type with a "hump". The Transil makes a huge difference to arcing at the points, reducing arcing to practically zero which greatly improves trouble free operation.

Black "hump" top cap, no air hole, made of a soft plastic (perfectly functional but does not look quite right imho): https://sucarb.co.uk/su-fuel-pumps-spar ... -hole.html

Black "stepped" top, no air hole, made of a hard Bakelite type plastic (looks correct): https://sucarb.co.uk/su-fuel-pumps-spar ... -hole.html

If you want to be absolutely perfect about it, this little washer (not included in the rebuild kit) goes on the stud that goes through the top cap and cushions and helps to seal the top cap in conjunction with the adhesive sealing band between the cap and body (if you don't have an SU one, use masking tape). https://sucarb.co.uk/misc-part/washer-10.html

Parts diagram (scroll down): https://sucarb.co.uk/su-fuel-pumps-spar ... ity-1.html

If you paint the body of the pump to show off your hard work refurbishing it, remember that the earth screw must make a good electrical contact.

Stephen

KevinB wrote: ↑Sat Mar 07, 2026 8:41 pm These parts have arrived, plus others of course.

20260307_160605.jpg

Supposed to be for a pre-1985 pump, I think the new diaphragm is? (looking at Stephen's thread)..
https://board.mmoc.org.uk/viewtopic.php ... t=Su+AUA66

I smiled when checking the workshop manual - it says the old, dirty pump should be cleaned with caustic soda, followed by strong nitric acid. Not sure how easy they are to buy, these days?

Not started the dismantling yet.

Caustic Soda is easy, many drain cleaners contain it but Nitric acid, no not readily available! I really don't think either are a good idea on Aluminium but the very early pumps had a brass valve body. Nonetheless a bit too brutal.

An ultrasonic cleaner is marvellous for cleaning small components. Failing that, hot water, washing up liquid and an electric toothbrush with a worn out brush head works very well. Obviously do not wash the body of the pump that contains the coil!

Stephen