SU Fuel Pump Explained - Common Faults and Fixes 

Hi thanks to this video we managed to sort out the issue with the SU petrol pump on our 1964 Mk2 Jaguar. So thank you for doing this it's very much appreciated. Graham (UK)

Thank you Adam, you are easy to understand with your gentle and concise manner. Much appreciated from a silver haired youth! 👍👍

I feel like drop-kicking my su pump across the field. I took it apart yesterday to find a perished diaphragm and luckily I had another crusty old pump laying around in my spare parts pile that's luckily probably never seen ethanol, nicked the diaphragm from that and put it in my working one. Now I can't seem to get it to operate, I'm pretty sure after watching you're video that I'm not screwing the diaphragm in to the correct tension. I'll go out and have another go in a bit, thanks.

Great description, Adam, thanks for sharing. My first introduction to the SU fuel pump was many years ago when my MkII Jag broke down on the side of the road. I had no idea the fuel pump was in the boot. Took another friendly Jag driver (in a V12 XJS) who stopped and showed me where the pump was and how to clean up the points. Was very thankful that day! Have rebuilt a few since that day about 30 years ago!

great video Adam, thank you. Just did the points on my Daimler Dart SP250 that had stood over the winter and refused to start as the SU pump wasnt working. Cleaned up the points and off she went! The best thing were the close ups with the description, of how to measure the points gap. Other vidoes by othersare not half as clear. well done.

Thanks for the vid. I had a MGB that had not been started in 12 years. I couldnt even get a twitch out of the fuel pump. I took out the top points and used a brass brush to clean everything and took off the top and took out the diaphragm to make sure it was moving. Its now working correctly. One thing I notice that was not in your vid was that the threaded hole the diaphragm screws into can turn sideways on you and you have to get a small screw driver or piece of wire in there and rotated it back to get the diaphragm to start threading back into it. Thanks again for the vid. It was a really helpful tutorial.

Thank you good job on simplifying the SU fuel pump. Good Job!!

I've never stripped the pump on my '66 Mark 2, so this was extremely helpful. Thanks Adam!

Very useful video, quite rare to get details on this organ. Many thanks !

Thanks for this very useful video. I have an SU pump that works when the valve body is off but not when it is screwed up. There is only one contact point and no condenser. I'll have a check of the points clearance now. Cheers.

Great Video. Very informative. 👍

Thanks for this video,Adam.My S1 arrived Wednesday evening,and it hasnt stopped raining since! There is no noise from either of the pumps,so ill check power is getting there,if it is,its points cleaning time:)

Very helpful,nice one mate .

I've owned about 20 Jaguar saloon cars from the Mk VII to the Daimler DS420 that used these pumps. I've only had to replace one diaphragm ever, but had to clean the points on every other one to get them running at one time or another. There's a product made for pinball machine repair that is a very thin contact cleaner. It looks like a plastic nail file. It's thin enough that it doesn't spread the points apart that much, and strong enough to clean the contacts up and leave them nice and straight in just a few swipes. The contact cleaner and a big wrench were my go-to items to get an old Jaguar running. The big wrench is used to smack the Lucas M100 starter on the side to get the brushes to release from the armature when you turn the key, hear the relay click on the starter, but the engine doesn't turn over. Works EVERY time.

superb. well done.

Hi Adam, Thank you for this highly interesting video! It encouraged me to take out and diassemble the SU fuel pump of my 1966 MGB, which has been parked for 7-8 years and service it, yet when I opened it, I found what appears to be an electronic control board instead of the rocker/contact points assembly. Now I´m back to the start, I guess.. :-) Best regards, Martin

hello sir very good video . i have am issue with my xk120 jaguar. after around 2 hours driving the pump seams it stops . after cooling down it goes agian . is there a kit o can buy for the pump ?

Thank you for recording this! I was able to see how to disassemble and access the points from your video. I did not fully disassemble like you did - I only popped the top cap off, removed the top point (easy), brushed the points clean with a scruff pad, reached down and did the same to the bottom points (without disassembling them), screwed the top point back on, dipped a Q-tip in apple cider vinegar and wiped off the surfaces, reassembled and installed, and I have a working fuel pump again! Thanks!

I'm happy to find your video because i have an issue with the pump of my 1975 MGB. The cork gasket is totally deformed, and i think i have to replace it. Do you think the cork could ne replaced by a rubber one ?

Is there some sort of filter inside the body which needs cleaning after several years? Many thanks

I have the AZX1307 pump on a '61 Austin Healey 3000 BT7 and it was working fine before being stored for several months. The points appear to be a excellent condition, but I cleaned them anyway to be sure. Still getting nothing when connected to a 12V battery. No clicks. Could the issue be the condenser?

I did not see a "thrust washer" located inside the top half , looks to fit in narrow end of spring? It is refereenced in the rebuild kit I go but, I did not have one in the pump when I disassembled the pump? Your thoughts.

Hello. Can you give your oppinnion what could be wrong. My s1 (1969) right fuel system wont work. I have changed the pre pump fuel filters on both pu pumps today as they where brown. The su pump in question appers to work as it clicks 2-3 times then stops but the pre filter wont fill from the tank. There is only abt 1/4 full of fuel in the plastic filter housing. When changing over to the new filters the flow of fuel from the tank in question appeared ok. Could there be a damage fuel pump, membrane or just ditt inside so it doesnt suck? Or to much air in the filter that is before the pump? Your response appreciated.

I need to do this on my Corniche. It has the dual pump too. It seems to leak, but it's not clear to see exactly where it leaks. Is it the main diafragms, or could it be the ones in te chambers?

Thanks from Scotland

What happens to the pump if converted to negative ground? Thank you in advance for your answer.

EL mejor video, si estaría subtitulado en español sería formidable.

Hi Adam, having just rebuilt my SUs on my Silver Spirit, I think the fuel pump is not delivering enough fuel, what is the fuel delivery rate?

I have an Mg Td that has a spare put as well as one on the car. I have an issue with the points on both pumps. The one on the car is similar to you film but the point only have one point and no way to adjust. The spare pump has 2 points as in your film but the Bakelite base which the top points fix to is different in that it is a cut out where the point go through and not a rectangular hole. So there is no way to set the points. The bottom spring loaded points seem to be pushing hard against the top points as there is no Bakelite edge on the base plate to push up to. Also is it possible to fit a capacitor to prevent the points burning? What capacity would it be?

Hi, The fuel pump on my Lotus Eclat had stopped pumping and I was all set to purchase a new one......anyway after watching this video I spent half a hour stripping and cleaning the points and yes when the pump met 12 volts it started ticking again and the carbs started to get fuel. Thanks. Simon

Fascinating--at least to me, not being mechanically inclined. What would be really helpful to me if you could manage it is to install a really good camera directly above your workbench so you can zoom in on those small bits (screws, nuts, points, etc.) and that way I could see where exactly they fit in.

Should the center drive post be lubricated?

Hi ive got the azx 1307 su fuel pump no points electronic on my 1952 jaguar mark vii when I put power to it it won't pump the large diaphragm won't pump up and down it just go's up once then stops

If you would, should the su pump always be clicking or does it ultimately stop when carb or lines to carb are full?

HELP> I assembled the pump, the gaps were good, i backed off the diaphragm....but it wont run. taking the top half off and powering it up it wont run....but if i press up lightly on the diapragm....THEN it runs. What did I do wrong to cause this?

I the time 2:56, there is on the top cover visible plastic cap (elbow) what is inside there?

Mine is always clicking and never stop. It goes faster when press accelerator

What is the small nipple on the side for.

Great video! But a serious question: How many drugs were consumed during the design of this monstrosity? The British never did ANYTHING easy, did they?

They don’t all have a condenser.