# Gaggia Classic group head leak after changing the seal



## Dosani1977 (Apr 4, 2020)

Hi all

Newbie here, but this forum is a great help!

I recently purchased a used Gaggia Classic from 2004. Unfortunately it wasn't in the best condition, so I completely descaled it, took the shower plate and screen off etc.

All was working fine for a few weeks, then it started leaking from the group head, but only when coffee was in the portafilter.

Today I replaced the group head seal with the Cafelat blue silicone seal. It sat flush in the space and with the flat side down

For some reason the leak is even worse, and only with coffee in the portafilter.

I've got the standard Gaggia classic non pressurised basket and am putting in 17.5g.

The shower plate and screen are completely clean and installed properly.

Is there anything else I should look out for?

Any help appreciated!

Thanks

Amit


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## JPChess (Feb 15, 2019)

@Dosani1977

Couple of points:



Is the seal/gasket the correct way (writing into the body of the machine and flat surface towards porta) - Looks like you have from your post.


Is the portafilter locked in all the way? , new seals are fully extended and may require more force then your used to until they compress/settle.


Is the mating surface of the portafilter clean (no grounds) and free from chips/defects/dents.


Using a torch, with the portafilter removed inspect the underside of the machine, anything obstructing the filter locking in (such as stray bean etc)


I assume its leaking from the right side of the group head as you look at the machine?


When you inserted the new seal, was the space the seal goes into completely clean?

If all of the above are clean it may be a duff seal/gasket (maybe not the correct thickness) long shot but hey.
Hope that helps.
JP


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## Dosani1977 (Apr 4, 2020)

Thank you so much JP. It's leaking from the back of the group head - ie the area closest to the water tank.

I cleaned everything before putting the seal in, and then before putting in the shower plate and screen.

As before, the portafilter doesn't got to the straight position with the basket in, but is now much closer to the centre.

I tried running it again but this time with only 15g of coffee. This time there were no leaks.

Not sure if it is a duff gasket or maybe the pressure is too high or the grounds are too fine? With 17.5g it wasnt coming out too slowly through the portafilter, if anything it was gushing out through the side.

I haven't tried the OPV mod yet.

Wonder if also the seal just needs some time to bed in!

Thanks for your help!

Amit


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## JPChess (Feb 15, 2019)

@Dosani1977

If the grounds are too fine, the OPV will ensure the water is diverted at a set pressure (depends what it is set to) however with the portafilter fully in its position the gasket should be able to hold this pressure.

When you say you are using the standard gagging classic none pressurised basket. Are you referring to the standard double basket?

Part No. NF08/005

If so the max you should be dosing into this is 14 grams, if you aiming to put in 17.5g into this the coffee puck will restrict the portafilter from locking in correctly and you will see some leaking.

JP


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## Dosani1977 (Apr 4, 2020)

Thanks @JPChess

Yes, it's the standard double basket. I can't see a part number printed anywhere.

Will try and use at 14g and hopefully that solves the problem, and then look to buy an 18g basket.

With an empty basket in the portafilter, it doesn't get to the 6pm postion, only about 6.30. Without the basket, the portafilter gets to about 5pm position. I presume that's normal?

Thanks

A


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## JPChess (Feb 15, 2019)

@Dosani1977

From memory the standard double basket is 14 Grams.

Just looked at mine, with the basket removed my handle aligns with the right corner of the main body above the group head. Around 4:30-5.

With basket in I would say around 5:30 ish.

However i'm using a VST basket and bottomless portafilter.

Try Dosing at 14 grams see how that goes.

Cheers and have a good Night

JP.


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## Dosani1977 (Apr 4, 2020)

@JPChess thank you! Have a great night. Amit


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## Agentb (Feb 11, 2017)

Dosani1977 said:


> haven't tried the OPV mod yet.


 I would recommend this if you are using the unpressurised baskets, it's easy to do and costs basically nothing.👍

If you are thinking about new baskets, i have both the 20g and 18g VST - depending on the coffee and size of drink i want to make. The 20 is a little easier i would say but mostly i use the 18g.


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## Dosani1977 (Apr 4, 2020)

@Agentb thank you!


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