# Londinium piston seals - how I fitted mine.



## Norvin (Sep 10, 2014)

[IMG alt="" data-src=""]https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png[/IMG][IMG alt="" data-src=""]https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png[/IMG][IMG alt="" data-src=""]https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png[/IMG]The shot volume was going down and it continued to drip for ages after I removed the cup so I decided to renew the seals. I have since found out that I may have got away with regreasing the seals, but there you go. I had set aside about 30 mins for the job, little did I know... The old seals came out easily enough but putting the new ones in without damaging them or the piston was another matter. The seals were too tough and would not stretch over the piston, I have seen the youtube video where someone uses wire to guide the seal, Reiss suggests using small allen keys but I couldn't do it and didn't want to risk damaging the seal or the piston.

[IMG alt="" data-src=""]https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png[/IMG]Here is how I did it. A few turns of copper shim were wrapped around the piston so that the seal could slide over without getting caught on the sharp edges of the piston grooves. A longer piece for the furthest seal and a shorter piece for the middle seal. I fitted the seal to the piston using an adapter that I had made to fit a camera hood to a Rossi grinder but have since found that an end fitting from a 25mm MDPE fitting (about £3.50 from Screwfix) looks even better as it has a taper on the end to aid stretching the seal and is the right diameter.

The piston is back in the machine now but here is a picture of the bits mentioned, an old seal is s[IMG alt="" data-src=""]https://www.coffeeforums.co.uk/applications/core/interface/js/spacer.png[/IMG]tretched over one fittiing,

I hope that this helps someone. If anybody wants to try, send an SAE and I'll send some shim.


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## NickR (Jul 1, 2011)

Thanks Norvin. I changed my seals about a month ago, using the recommended technique of 2 allen keys. It was a struggle. It occurred to me afterwards that wrapping some thin metal around the piston to stop the seals falling into the grooves, would have made the job alot easier. I was thinking along the lines of some metal from a baked bean can, but your solution is alot better. Next time...


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## ashcroc (Oct 28, 2016)

NickR said:


> Thanks Norvin. I changed my seals about a month ago, using the recommended technique of 2 allen keys. It was a struggle. It occurred to me afterwards that wrapping some thin metal around the piston to stop the seals falling into the grooves, would have made the job alot easier. I was thinking along the lines of some metal from a baked bean can, but your solution is alot better. Next time...


A coke/beer can would be a lot thinner than a bean can & should still be strong enough to act as a shim.


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## Norvin (Sep 10, 2014)

Yes, cutting up an aluminium drinks can into spiral strips is easy and will probably work just as well.

I was really struggling until I decided to improvise, once I hit upon a solution the job became easy.


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## 9719 (Mar 29, 2015)

@Norvin for next time you have to change your seals looks fairly simples other than finding a cone to fit, no doubt @MildredM wonderful hubby Ian could fulfill that part minus the ice cream :classic_blink:


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## Norvin (Sep 10, 2014)

I thought about making something similar but it seemed a bit excessive for a single or very occasional use. Far more satisfying to overcome a problem with bits found after a trawl around the garage ?.

Am I the only person who thinks about that bit in 'Zen and the art of Motorcycle Maintenance' when cutting up beer cans for shims?


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## MildredM (Feb 13, 2017)

I have always wanted an aluminium cone ? now, where on earth can I order one @Nicknak ?


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## Nicknak (Aug 10, 2018)

MildredM said:


> I have always wanted an aluminium cone ? now, where on earth can I order one @Nicknak ?


 How can you ask me that in front of the Master , Norvin , he is a proper engineer ?


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## Norvin (Sep 10, 2014)

Er, accomplished bodger more like. Have you seen the first post?


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## Nicknak (Aug 10, 2018)

Norvin said:


> Er, accomplished bodger more like. Have you seen the first post?


 Just like me then , you were my hero ?..


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## MildredM (Feb 13, 2017)

Flipping 'eck! I keep putting my foot in things today ?


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## MildredM (Feb 13, 2017)

This has reminded me - I'd really, really like an aluminium cone very much ? ???


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## Norvin (Sep 10, 2014)

MildredM said:


> This has reminded me - I'd really, really like an aluminium cone very much ? ???


 Now where would be the fun in that? Much more satisfying to play about with plumbing fittings and strips of metal?. Maybe I have made it look more difficult than it really is in practice.

The cone would be reasonably straightforward to make but would be overkill if only used once a year/every couple of years. Let me know if you are still interested and I'll look into costings.


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## 4085 (Nov 23, 2012)

Did anyone ever find a contact to make these cone things? I would certainly take one


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## Norvin (Sep 10, 2014)

dfk41 said:


> Did anyone ever find a contact to make these cone things? I would certainly take one


 Dave, I've just offered to make Milly one. I'll look into costings in the next few days, Are the same sized seals used in the L1 and LR?


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## MildredM (Feb 13, 2017)

Norvin said:


> Now where would be the fun in that? Much more satisfying to play about with plumbing fittings and strips of metal?. Maybe I have made it look more difficult than it really is in practice.
> 
> The cone would be reasonably straightforward to make but would be overkill if only used once a year/every couple of years. Let me know if you are still interested and I'll look into costings.


 Yes please ?


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## 4085 (Nov 23, 2012)

Norvin said:


> Dave, I've just offered to make Milly one. I'll look into costings in the next few days, Are the same sized seals used in the L1 and LR?


 am pretty confident that they are matey, as the Londinium website does not offer a choice. As always a top man with a generous offer. I still use the metal ring you made me ages ago! One day, perhaps I will be able t return the favour!


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## Norvin (Sep 10, 2014)

Ok, just ordered enough material to make seven cones, using the dimensions of a cone given on another forum. Assuming that everything works out and they work, cost will be £30 each including delivery by Herpes.

Three are spoken for, if anyone else wants one, let me know.


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## Snakehips (Jun 2, 2015)

@Norvin Would you please add me to the list.


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## Norvin (Sep 10, 2014)

Snakehips said:


> @Norvin Would you please add me to the list.


 Of course. Three left, assuming that I don't cock any up.


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## 4085 (Nov 23, 2012)

One again, many many ta's.......I will become the proficient engineer type, one day! I can see folks with L1's within striking distance, ringing me up to bring my trusty Norvin cone along.....or maybe not!


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## scots_flyer (Jun 23, 2014)

Norvin said:


> Ok, just ordered enough material to make seven cones, using the dimensions of a cone given on another forum. Assuming that everything works out and they work, cost will be £30 each including delivery by Herpes.
> 
> Three are spoken for, if anyone else wants one, let me know.


 Can you add me too please?


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## scots_flyer (Jun 23, 2014)

Can you add me too please?


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## Norvin (Sep 10, 2014)

scots_flyer said:


> Can you add me too please?


 Added.


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## Asgross (Jun 14, 2015)

Hi
If I'm not too late, please put me down for one as well
Thanks.

Sent from my iPhone using Tapatalk


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## Norvin (Sep 10, 2014)

Asgross said:


> Hi
> If I'm not too late, please put me down for one as well
> Thanks.
> 
> Sent from my iPhone using Tapatalk


 Added, one left.


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## MildredM (Feb 13, 2017)

Norvin said:


> Added, one left.


 Meeeeeeeeeeee please ? ? ?


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## Norvin (Sep 10, 2014)

MildredM said:


> Meeeeeeeeeeee please ? ? ?


 I've already included you, you are my Guinea Pig (hah, see what I did there), just like you were with the hoppers.

Still one left.


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## coffeechap (Apr 5, 2012)

Add me ad well please


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## Norvin (Sep 10, 2014)

coffeechap said:


> Add me ad well please


 Ok,Last one. That's all folks. Depending on how things go, I may make some more in future if there is a demand. In which case I'll post a new thread in the for sale section.


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## MildredM (Feb 13, 2017)

Norvin said:


> Ok,Last one. That's all folks. Depending on how things go, I may make some more in future if there is a demand. In which case I'll post a new thread in the for sale section.


 Thank you very much for this @Norvin ? ?


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## Deidre (Aug 13, 2019)

This is a terrific invention!?? ?

(And, I hope one of you lucky folks will make a video showing it in use! ?☺)


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## Stevebee (Jul 21, 2015)

If you do make more - or if someone drops out - add me to the list. Using Cafelat at the moment but if I go back to Londinium seals this will be a godsend


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## 4515 (Jan 30, 2013)

Stating my interest in this too, should you decide to make a second batch


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## Phil104 (Apr 15, 2014)

A great idea, and stating my interest too.


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## MildredM (Feb 13, 2017)

With all this interest I'm thinking of offering a tube-hire service ??


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## Jollybean (May 19, 2013)

..and I will take the last one please


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## Jollybean (May 19, 2013)

Please ignore this. Got over excited at the end page one and didn't realise there was a page two ?

Please add me to the second batch list if you do some more


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## NickR (Jul 1, 2011)

If you make another batch, please put me on the list.


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## Norvin (Sep 10, 2014)

Thanks for the interest everybody, I had no idea that there would be such a demand.

If everything in the first batch goes Ok I'll post a thread in the for sale section. Rather than extending this thread with expressions of interest it may be best to wait for the thread to appear and order directly.


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## Norvin (Sep 10, 2014)

A quick update.

The first cone is finished, I am sending it to @dfk41 today as he has rubber seals ready for fitting, so hopefully can identify any problems before I make any more. I don't want to remove my recently fitted (expensive!) seals to test in case I damage them

It took a lot more time to make than I anticipated, so any future ones after this trial batch will be more expensive.

Some thoughts; I am thinking of putting one out there on a 'pay it forward' basis for those people who only need to use one once every one to three years or so. In order to limit access to active forum members, access limited to those with a minimum of 20/30 likes? No charge but the option to send me the price of a pint. Anyone who has ordered one in the first batch can cancel and be first in the queue for the loaner.

Am I right in thinking that this will fit not just Londinium but any Bosco piston?


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## Stevebee (Jul 21, 2015)

Does the cone slide over the first 2 seals to enable it to slide off into the groove for the furthest one. Then repeat for middle one etc..

The photo looks like it won't slide over the seals but it's tricky to see in the photo and would have to be a snug fit to work easily.


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## Norvin (Sep 10, 2014)

Stevebee said:


> Does the cone slide over the first 2 seals to enable it to slide off into the groove for the furthest one. Then repeat for middle one etc..
> 
> The photo looks like it won't slide over the seals but it's tricky to see in the photo and would have to be a snug fit to work easily.


 No, it won't slide over the seals. Starting with no seals in place, fit the seal furthest from the end, then the other two in order. The second picture shows what it would look like after fitting the third seal.


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## 4085 (Nov 23, 2012)

Norvin said:


> No, it won't slide over the seals. Starting with no seals in place, fit the seal furthest from the end, then the other two in order. The second picture shows what it would look like after fitting the third seal.


 So in other words it will slip over the piston when there are no seals in place allowing a simple roll off the tool into the first seal to be fitted position, then pull it back to repeat for the other two?


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## Norvin (Sep 10, 2014)

dfk41 said:


> So in other words it will slip over the piston when there are no seals in place allowing a simple roll off the tool into the first seal to be fitted position, then pull it back to repeat for the other two?


 Yes, that's correct, although I would fit the seals one at a time. The wall on the end of the cone is thin aluminium so having three seals constricting it at the same time may cause problems? Soften the seals first by immersing them in hot water and fit using a little grease.


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## Nicknak (Aug 10, 2018)

Norvin said:


> A quick update.
> 
> The first cone is finished, I am sending it to @dfk41 today as he has rubber seals ready for fitting, so hopefully can identify any problems before I make any more. I don't want to remove my recently fitted (expensive!) seals to test in case I damage them
> 
> ...


 Nice job ... I did think at the time you mentioned doing them they were too cheap .. Perhaps you have a CNC machine ???


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## Norvin (Sep 10, 2014)

Nicknak said:


> Nice job ... I did think at the time you mentioned doing them they were too cheap .. Perhaps you have a CNC machine ???


 Unfortunately no. Just a knackered Myford ML7 with a knackered operator.


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## Nicknak (Aug 10, 2018)

Norvin said:


> Unfortunately no. Just a knackered Myford ML7 with a knackered operator.


 I know the feeling , The other day I was thinking I need a powered cross slide and top slide ?


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