How to Replace the Group Gasket on La Marzocco Machines
How to change the group gasket on a La Marzocco
The La Marzocco group gasket is made of silicone. Over time, this part wears and dries out due to it being a high volume wear and tear part. This affects the seal between the gasket, and the portafilter, causing leaking from around the portafilter during the pulling of a shot. This is one of the most frequently replaced parts in an espresso machine, as it is integral to a good shot, and should be a part of routine preventative maintenance every 12-18 months. This guide provides detailed instructions for replacement of the group gasket, shower screen, and screw. 
Replacing the group gasket is the first step in performing annual preventative maintenance on your espresso machine, making sure the machine is always functioning at its highest potential.
Difficulty Level: Easy
Tools Required:
- Gasket Pick or Mechanic Pick
- Microfiber Towel
- Flat Head Screwdriver
- Shower Screen
- Diffuser Screw
- Silicone group gasket
Instructions:
Safety First: Turn off, and unplug your machine 2 hours before beginning, to ensure it is cool enough to touch The grouphead remains hot for a while, so make sure to give yourself enough time to let it cool completely.
Remove Diffuser Screw & Screen: Remove the diffuser screw and shower screen with a short, flat head screwdriver.
Remove Old Gasket: Using the gasket or mechanic pick, poke the gasket and pull it out for removal. Please note, depending on the age of the gasket, it could break/crumble - this is okay, just make sure to remove it completely.
Clean Bayonet Ring: After removing the gasket, clean out the inside of the bayonet ring with a soft towel, to make sure no residue or gasket particles are still inside.
Install Gasket: Insert new gasket into grouphead with the flat side facing up towards the machine, and the beveled side down where the portafilter will seal onto. If you choose to use a robber gasket, add a bit of molykote, or food safe silicone grease, to the flat side of the gasket before inserting it into the machine.
Seat Gasket: Use the back of the gasket pick to push the gasket into the groove.
Secure: The process is completed by inserting the portafilter into the bayonet ring a few times, akin to the usual process of sealing the portafilter into place. The rim of the basket should engage with the gasket to seat it properly.
