Changing the Grouphead Seal/Gasket on Nuova Simonelli Espresso Machines
Replacement of the grouphead seal is a maintenance task required on all espresso machines. The frequency that the seal requires changing will depend largely on the usage of the machine and you can expect to change them every 2 to 6 months.
Over time, the material of the seal becomes hard with the heat from the grouphead. The harder the seal gets, the more difficult it is to achieve a seal that will hold the grouphead pressure. As a result a leaking of extracted coffee will be observed around the portafilter/handle when extracting a shot.
This can also be caused sometimes by a build up of coffee grinds in the grouphead if cleaning is not up to scratch.
It is recommended that your machine is switched off and allowed to cool before attempting to replace the seal and/or other grouphead components.
To remove the old seal, use a study sharp tool (a sharpened screw driver or other spike type tool), push it into the old seal and then lever it out of the groove it sits in. This can sometimes be more difficult than it sounds, as the seals can become very hard and difficult to penetrate. The seal will often break up and come out in pieces rather that in one piece. Ensure all the pieces are removed.
Now thoroughly clean the grouphead, paying particular attention to the groove the new seal will sit in. Use your barista brush, followed up by a damp cloth, to remove all grinds and residue from the grouphead.
When replacing the seal, it is also a good opportunity to remove (and replace if necessary) your shower screen/foil. Remove the screw in the centre of the screen and this will allow the screen and dispersion plate to be removed. Thoroughly clean all components (avoiding abrasive materials on the dispersion plate). Hold the screen up to the light and ensure that you can see light through the fine holes in the screen. Replace any blocked or partially blocked screen that cannot be cleaned.
Note the order and orientation during removal and ensure components are reinstalled correctly.
When installing the new seal, ensure it goes in the correct way. Genuine Nuova Simonelli seals have lettering on one surface. This surface goes upward into the groove (ie, opposite face to that which seals with the portafilter). Some machines can us a bevelled/taper seal rather than a square seal.
The bevel/taper is outward (ie, contacts with the portafilter)
A firm push to get the new seal into the groove will be required. (If your machine has been on, the grouphead will be HOT, so care is required.) The portfilter can then gently be used to push the seal all the way home. Wipe clean, purge with water and check operation. Enjoy your brew!
For further help, google “changing grouphead seals” and check out any videos that are available.

Group Head
Wire Spring
Seal
Dispersion Plate
Shower Screen
Screw
Basket double
Basket single
Handle Components
Handle Body
Spout
Spout